Gas Water Heater – CheckThisHouse https://www.checkthishouse.com Home maintenance, remodeling, repair, and improvement tips for your property Tue, 13 Apr 2021 22:28:34 +0000 en-US hourly 1 https://wordpress.org/?v=4.9.17 Water Heater Inspection Guidelines & Home Inspector Tips https://www.checkthishouse.com/6300/water-heater-inspection-home-inspector-tips.html Wed, 07 Dec 2011 00:23:17 +0000 http://checkthishouse.com/?p=6300 Hot Water InspectionWater Heater Inspection Guidelines The following water heater inspection guide covers 3 types of the most popular water heater installations: Gas, natural draft, tank water heaters utilizing galvanized steel vent pipe Gas, power vent equipped, tank water heaters utilizing PVC vent pipe Electric water heaters There might be some minor discrepancies between jurisdictions which will in most (probably not all) cases concern seismic areas water heater installations. I’ll cover it within this water heater inspection manual but I would highly recommend to obtain a water heater installation permit from your local building department (usually required) and verify plumbing code requirements in your particular area. Water heater [...]]]> Hot Water Inspection

The following water heater inspection guide covers 3 types of the most popular water heater installations:

  1. Gas, natural draft, tank water heaters utilizing galvanized steel vent pipe
  2. Gas, power vent equipped, tank water heaters utilizing PVC vent pipe
  3. Electric water heaters

There might be some minor discrepancies between jurisdictions which will in most (probably not all) cases concern seismic areas water heater installations. I’ll cover it within this water heater inspection manual but I would highly recommend to obtain a water heater installation permit from your local building department (usually required) and verify plumbing code requirements in your particular area.

Water heater inspection general requirements, most apply to all 3 categories of water heaters

Water heater inspection –  cold water supply line and a shutoff valve

There must be a water shutoff valve installed ONLY on a cold / inlet line of the water heater. This is required for the emergency and servicing purposes; so the water flow can be easily turned off in case of a leak or appliance servicing.

The water shutoff valve must be installed at or near the water heater / only a full-bore valve type is permitted for this purpose.

Water heater inspection – hot and cold water line connections

Water supply and distribution line material requirements vary between jurisdictions. They might be copper, plastic, galvanized, or even lead in older buildings.

While performing water heater inspection check for union connectors; they are required within 12″ from the water heater’s inlet and outlet side. Their type will depend on the water pipe material in your home. Dielectric and brass unions are safe for all types of water pipe materials (required for copper water pipes) because they provide required separation for different metal types to prevent their corrosion. Galvanized unions can be used for galvanized and plastic water pipes only.

Some jurisdictions will require / some forbid final water pipe connection to the water heater to be flexible. Also, some will require heat traps / heat loops on those flexible lines. I believe that most of the new water heaters will have heat traps built in, if not, a curved flexible line directly above the appliance servs the same purpose; allows cold water to flow into the hot water heater’s tank and prevents hot water convection / mixing with cold water and flowing out of the tank when not in use.

Installed water heater lines union connectors should be checked for leaks during the water heater inspection.

Water heater inspection – hot and cold water pipes insulation

If you jurisdiction adopted UPC (Universal Plumbing Code), minimum R4 thermal resistance value insulation might be required on hot and cold water pipes withing 5′ from the water heater’s inlet and outlet.

Water heater inspection – hot water recirculating pipes

Some water heaters have a hot water recirculating loop installed, which guarantees instant hot water at the furthest faucet from the water heater. Unfortunately such installation wastes significant amounts of energy and all of the recirculating hot water pipes might require to be insulated.

Water heater inspection – insulation

Most newer water heaters include integral R12 or higher value insulation and do not require additional external blanket insulation installation. However, in case the water heater has a lesser value integral insulation or it has been installed in an unheated area, extra layer of insulation is recommended and might be required.

Water heater inspection – thermostat temperature settings

Water heater thermostat temperature setting is a serious safety issue but not a code requirement. The most recommended setting is under 125°F (48,88°C). But continuous exposure of a child’s skin can even at that temperature result in 2nd or 3rd degree burns.

Water heater inspection – safety drip pan

Tank type water heater installations in areas where leakage could cause damage require protective watertight drip pan underneath. This requirement also applies to a cabinet / under the countertop installations.

  • Protective pan must be made from an approved material; minimum 24 gauge galvanized steel or plastic
  • Its minimum depth must be 1 1/2″
  • It must have a minimum 3/4″ drain with a discharge pipe pitched for proper drainage into an approved location. Depending on your local adopted code this could be over a suitably located indirect wastereceptor or floor drain (it cannot be connected to a sewer line, vent pipe, etc.) or outdoors within 6″-24″ from the ground

Water heater inspection – TPR valve  (Temperature Pressure Relief valve)

All tank type water heaters must have a properly installed TPR valve! Every TPR valve must have a properly sized and made out of an approved material safety discharge pipe attached to it.

Since this is an extremely important water heater inspection topic and serious safety issue, please follow this link to a dedicated article: water heater pressure relief valve

Water heater inspection – expansion tank

An expansion tank would be required if a check valve / back flow preventer has been installed on a cold water supply line creating what is referred to as closed water system.

Water heater inspection – combustion air requirements for any fossil fuel burning appliances

Sufficient amount of combustion air MUST be provided for the water heater to operate properly and to prevent incomplete combustion which might result in producing elevated levels of Carbon Monoxide gas.

Water heater inspection – gas connectors

Some states (including Illinois) require heavy wall gas pipes or CSST (Corrugated Stainless Steel Tubing) as a water heater’s final gas connector. No appliance type (commonly used for gas ranges and clothes dryers) flexible connectors are permitted in Illinois.

However, there are jurisdictions where flexible connectors might be recommended or required in water heater installations (seismic areas). Therefore, while performing water heater inspection, gas connector type should be verified with a local building department, and / or gas lines servicing utility company.

Common requirements for a gas flexible connector are that it cannot run through or be concealed inside any wall, floor, or other partition. Also, gas flexible connector should not come in contact with objects like metal wall studs, electrical wiring, copper or iron piping, paneling, sheet metal, etc.

Maximum length of a flexible water heater gas connector is 3 feet.

Water heater inspection – gas shutoff valve

Water heater must have a dedicated gas shutoff valve installed within 6 feet from the appliance, in the same room as the WH, and upstream of the union connector. Where a flexible connector is used, the valve must be installed upstream of the connector.

Water heater inspection – gas line union connector

A union or flanged connection is required between the gas shutoff valve and the water heater. Flexible connectors already include flanged connector so no extra union is needed when using one of those. This is to allow removal of the water heater or its controls without removal of the shutoff valve.

Water heater inspection – drip leg / sediment trap

Water heater gas supply line should have a sediment trap (also known as a drip leg) installed to collect moisture and prevent possibility of  gas valve / thermostat contamination. It should be installed as close to the water heater’s gas valve / controller as practical at the time of equipment installation. Gas line’s drip leg can be in a form of a tee fitting with a capped nipple in the bottom or another device approved as an effective sediment trap. Again, this may not be required everywhere.

Garage water heater inspection

Follow this link – garage gas water heater – for explanation of such installation.

Water heater inspection – safety strapping

Tank type water heaters safety strapping might be mandatory in your area so please verify that with a local building department.

Based on the UPC (Uniform Plumbing Code) section 510.5, water heaters located in seismic zones 3&4 require strapping and / or anchoring to resist horizontal displacement caused by an earthquake. If you’re not sure about your seismic zone, use this US Seismic Zone Map (please let me know if the map is gone at that link) to determine it or call your local authorities.

The following general requirements stated in UPC might vary in your area: “Strapping shall be at points within the upper one-third (1/3) and lower one third (1/3) of its vertical dimensions.  At the lower point, a minimum distance of four (4) inches (101.6 mm) shall be maintained above the controls with the strapping”

Follow this link for detailed California Guidelines for Earthquake Bracing of Residential Water Heaters

Natural draft, tank type water heater inspection

Water heater inspection – draft hood

Water heater draft hood’s diameter depends on the size / BTU’s of the appliance. Residential size water heaters have usually 3″ or  4″ diameter draft hoods, some accept both sizes; the collar of the draft hood will have a profile that allows for different diameter vent pipes installation (picture).

A 3″ diameter draft hood should only have a 3″ diameter vent pipe directly attached to it. 4″ diameter vent pipe can be used as well but only with a reducing coupling.

In case the water heater and the draft hood have been designed to accept 4″ diameter vent pipe only, under no circumstances this pipe can be downsized!

New, 4″ diameter draft hood water heater installation in place of an old one that utilized 3″ diameter draft hood and a 3″ diameter galvanized vent pipe requires entirely new 4″ diameter vent pipe connector. No part of the old, smaller size water heater vent pipe can be re-used!

Water heater inspection – vent pipe vertical rise above draft hood

Although there is no UPC code that would mandate water heater’s vent connector having 12″ vertical rise above the draft hood, the Gama venting tables that are required for proper vent pipe / chimney calculations start with a 12″ minimum vent connector rise.

Water heater inspection – single wall vent pipe connections

All water heater single wall vent pipe connections must be secured with 3 sheet metal screws each (unless some other form of fastening has been approved in your jurisdiction) which includes draft hood connection. Using metallic duct tapes is generally not permitted on water heater vent pipes because it limits monitoring and prevents spotting corrosion and leakage signs, which should be investigated by a professional ASAP .

Water heater inspection – double wall / B-vent pipe connections

B-vent type water heater vent pipes require no screws on their joins because they utilize twist and lock connections. The only area that requires screws is the first joint with a single wall vent pipe or draft hood connection.

 

Water heater inspection – vent pipe clearance to combustible materials

  • A single wall water heater vent pipe requires minimum of 6″ clearance to combustible materials
  • Double wall / B-vent type connector requires 1″ clearance to combustible materials

Water heater inspection – single wall vent pipe locations

  • Single wall vent pipe cannot pass through any walls, floor, ceilings
  • Can be only installed in the same room as the water heater
  • Single wall vent pipe may never be installed inside the wall / ceiling cavities
  • Single wall vent pipe cannot be installed in an unheated or inaccessible area (attic, crawlspace)

Water heater inspection – vent pipe slope, support, and length

  • Water heater vent pipe requires a minimum of 1/4″ rise per linear foot towards the chimney to maintain proper draft.
  • The entire run of the vent connector must be sufficiently supported to prevent sagging and dipping.
  • Maximum horizontal length of a single wall vent connector is 75% of the total vertical height
  • Maximum horizontal length of a double wall / B-vent connector is 100% of the total vertical height

Water heater inspection – water heater and furnace vent pipe connection

Venting a furnace that utilizes induced draft motor and a natural draft water heater into a common vent requires “Y” shaped connection. This is required to prevent exhaust gases from the furnace from being pushed back into the house through the water heater’s vent pipe / draft hood.

Click – water heater venting – for an article dedicated to this subject.

Power vent, tank type water heater inspection

Water heater inspection – PVC vent pipe

Tank type water heaters utilizing power vent must have its PVC vent pipe joints sealed / glued using appropriate PVC cement that creates air tight joint. Using silicon for this purpose is not permitted.

The PVC vent pipe’s first connection to the power vent assembly collar is usually made with rubber sleeve / coupling and two clamps, which quiets vibration and minimizes its transfer onto the PVC vent pipe joints.

Water heater’s PVC vent pipe must be properly supported along its entire vertical and horizontal run to prevent sagging and dipping. Manufacturers span support recommendations vary between 3′-6′ with the first support / strap located immediately adjacent to the first 90° elbow. This might be further regulated by you local authorities.

The diameter and the minimum / maximum length of the water heater’s PVC vent pipe must be verified using the water heater’s installation manual. It usually depends on the appliance’s tank size, power vent motor,  BTU’s, and the number of elbows along the entire run.

Click the following link – water heater PVC vent pipe – for additional material covering water heater’s PVC vent pipe. You need it to complete this power vent water heater inspection .

Tank type, electric water heater inspection

Water heater drip pan, TPR valve and discharge pipe requirements are the same as above.

Water heater inspection – electrical connection

Electric water heater requires in-sight or lockable disconnect, 220V circuit breaker should be labeled accordingly.

Electrical conduit must be secured to the connection box with a listed type connector and wiring performed / concealed inside the compartment / protected with a cover.

Electrical conduit must not touch metal water pipes.

Electric water heater grounding terminal screw and grounding wire installed - water heater inspection

Electric water heater grounding requirement - water heater installation manual picture

Electric water heater requires grounding – a ground terminal is usually located inside the connection box or in its vicinity.

Green color wire or green tape marked wire must be attached to the WH grounding terminal and to the electrical service ground terminal.

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Anode Rod, WH shut-down & Combustion Air: Water Heater Maintenance Part 3 https://www.checkthishouse.com/6075/water-heater-maintenance-3-anode-rod-shut-down-combustion-air.html Sun, 17 Apr 2011 00:22:39 +0000 http://checkthishouse.com/?p=6075 You have reached Part 3 of Tank Gas Water Heater Maintenance Water Heater Maintenance Part 1 Water Heater Maintenance Part 2 Water Heater Maintenance Part 3 Use the navigation above to revisit Parts 1 & 2 of this important gas water heater maintenance procedure. Part 3 covers the following: Sacrificial Anode Rod maintenance Vacation and ... Read more]]>

You have reached Part 3 of Tank Gas Water Heater Maintenance

Water Heater Maintenance
Part 1
Water Heater Maintenance
Part 2
Water Heater Maintenance
Part 3


Use the navigation above to revisit Parts 1 & 2 of this important gas water heater maintenance procedure.
Part 3 covers the following:

  • Sacrificial Anode Rod maintenance
  • Vacation and extended shut-down of the water heater
  • Water heater’s combustion air – extremely important!

Tank gas water heater maintenance – the Sacrificial Anode Rod

The anode rod purpose is to prolong the life of the water heater’s glass lined tank. While protecting the tank from corrosion the rod deteriorates. It’s performance and the life span depend on the water conditions in your area, which will influence the time intervals for the anode rod’s evaluation, and replacement if such is required.

If you have a good quality water supply and you’re not using any water softening systems, water heater maintenance will not be that extensive and you can expect the sacrificial anode rod to last approximately 3-5 years. However, the softener system or an acidic water source will cut that time in half or even more thus increasing water heater maintenance

Therefore, my suggestion is to have a professional performing at least the first time evaluation of the water heater’s sacrificial anode rod. The plumber will be able to show you what tool would be the best to remove it (1 1/16″ socket wrench in most cases), how to determine the remaining life span of the rod, and hopefully come up with a time frame for the next check-up.

Water heater maintenance - most typical / exposed sacrificial anode rod hex head locationWater heater maintenance - replace deteriorated anode rodWater heater maintenance 3 – Tank water heater sacrificial anode rod access.
In most residential tank type water heaters it is fairly simple to locate the anode hex head screw on top of the appliance’s enclosure.

However, in some water heater tanks this access might be obscured and without information about a particular appliance design and extra tools you may not be able to find it – get a plumber.

Water heater maintenance 3 – Perform the anode rod maintenance inspection by following these steps:

  1. Turn off the water heater’s gas supply (lower the thermostat to minimum, set the regulator to OFF and / or turn OFF the shutoff valve) / turn off the electrical power supply if such exists
  2. Turn off the cold water supply at the water heater cold line and at the the main water shutoff
  3. Release the water pressure by opening any of the water faucets located below the top part of the water heater’s tank level. If you have any faucets on the floors above the water heater level, open those faucets as well and wait until there’s no water coming out of the lowest faucet (leave it open for the rod inspection)
  4. If there’s no faucets below the water heater’s top plate level (for example: a water heater located in the crawlspace or a basement with no extra sink) you’ll have to used the WH’s drain valve to release the pressure and drain water from the system
  5. Use a 1 1/16″ socket wrench to unscrew the rod (you may also need a breaker bar, especially on older water heaters)
  6. Carefully (to prevent it from breaking apart if severely deteriorated) pull the anode rod from the water heater’s tank and depending on its condition: clean it or replace it with a new one. I’ll try to get some pictures for you so you know what to expect.
  7. Reverse the procedures above

NOTICE:
Completely removing the anode rod from the water heater’s tank (except for inspection and/or replacement) will void the warranty and shorten the life span of the glass lined tank.

Tank gas water heater maintenance Part 3 – Vacation and Extended Shut-Down of the water heater

Whenever your water heater is to remain unused for an extended period of time, you can save money and energy by simply turning off the gas, power supply (in some models), and water feed to the appliance.  This will also prevent a build-up of dangerous hydrogen gas.

Hydrogen gas can be produced in a hot water heater that has not been used for some period of time, usually more than 2 weeks.

HYDROGEN GAS IS EXTREMELY FLAMMABLE!

To safely disperse such gas and minimize risk of injury, open the kitchen hot water faucet for several minutes prior to operating any of the electrical appliances that might be connected to the hot water system. Refrain from smoking or using an open flame near the faucet.

A typical hydrogen confirmation presence is a sound of air escaping through the open faucet as the water begins to flow.

Water heater maintenance 3 – Planning to leave your house completely unattended during the winter / concerned about freezing?

  • Consider draining the tank water heater and piping if they might be subjected to freezing temperatures. If it’s a long shut-down period, have a professional check your water heater’s operation. If you decide doing it on your own, make sure the water heater is re- filled completely prior to starting its heating cycle.

Water heater maintenance 3 – plumbing system draining pros:

  • If you turn off the water to your property and properly drain / air blow the entire system, you don’t have to worry about freezing, cracking  pipes, and flooding.

Water heater maintenance 3 – plumbing system draining cons:

  • Anode rod helps to protect water heater’s tank from corroding but only while filled with water. Even its interior walls are glass-like ceramic coated, its rust-resistance will be compromised when empty.

Final gas water heater maintenance requirement – combustion air (applies to all fuel burning appliances)

Gas water heaters require oxygen from air to burn its fuel (gas or oil), which is called a combustion process. Consequently, this air required for water heater’s combustion is called “combustion air”.

An insufficient amount of combustion air supply results in an incomplete combustion process. As a bi-product of such incomplete combustion, Carbon Monoxide is released to the WH surrounding area, and this could be deadly for you.
Unfortunately many of us don’t understand it or simply forget about it. Therefore, I highly recommend following this link and educate yourself about combustion air – combustion air minimum requirement

Some basics of the water heater maintenance concerning combustion air:

  • The water heater takes its combustion air through the openings around its base (sides and / or underneath the bottom plate). DO NOT block or obstruct any of those combustion air inlets. Keep anything at least 1” away from them.
  • DO NOT store ANY combustible materials (wood, paper, fabrics, etc.) or flammable liquids (paint, paint thinners, aerosol spray, gasoline, etc.) near the water heater.
  • Make sure that the water heater location has plenty of fresh air circulation – combustion air
  • Maintain functional Carbon Monoxide detector(s) and smoke alarms in your home – check Home Safety category for details.

That concludes Part 3 of the tank gas water heater maintenance, let me know if you have any questions. If this is where you have started from, make sure that you go over Parts 1 & 2 of water heater maintenance.

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Tank Gas Water Heater Maintenance 2: TPRV, Tank Drainage, Flue-Way https://www.checkthishouse.com/6049/tank-gas-water-heater-maintenance-2-tprv-tank-flue.html Sat, 16 Apr 2011 14:20:14 +0000 http://checkthishouse.com/?p=6049 Second part of the tank gas water heater maintenance explains: TPR valve maintenance, water heater tank drainage, and internal flu-way maintenance / venting.]]>
Water Heater Maintenance
Part 1
Water Heater Maintenance
Part 2
Water Heater Maintenance
Part 3

 

Part 2 of the tank gas water heater maintenance explains:

  • TPR (Temperature & Pressure Relief) valve maintenance – perform annually
  • Water heater tank drainage – a few quarts once a month
  • Internal flu-way / venting system maintenance – once a year

Tank gas water heater maintenance Part 2 – TPR valve maintenance, testing should be performed at least once a year by a homeowner and / or by a professional – licensed plumber.

Tank gas water heater maintenance - before testing TPR valve make sure it has a properly installed discharge pipe - Safety Hazard

DANGER: Before you start gas water heater maintenance and attempt TPR valve testing, make sure that there’s a properly installed and secured to the valve discharge pipe (click water heater’s TPR valve for details), and that no one will be exposed to the hot water released from the discharge line. Its temperature may be high enough to cause body injury or property damage.

Tank gas water heater maintenance - if possible, use the floor drain to test TPR valveTank gas water heater maintenance - with no floor drain use a bucket to test TPR valveIn case there’s no floor drain directly beneath the discharge line, place a bucket under the water heater’s TPR valve discharge pipe, and place a towel over the bucket to prevent water from splashing.

If you have water temperature set to hot or very hot, I would recommend pouring some cold water into the bucket prior to opening the valve in order to immediately lower the temperature of the discharging water.

Tank gas water heater maintenance - TPR valve locationsContinue with gas water heater maintenance and lift and release the lever handle on the temperature pressure relief valve (TPRV).  This will ensure that the valve is operating freely. TPRV is located near the top of the water heater, on its top or side wall surface. You should discharge a few gallons of water through the discharge line into an open floor drain.

You may also find the discharge pipe suspended directly above the drip pan under the water heater (some jurisdictions do not allow such installation / some do). I wouldn’t recommend discharging water into the pan. Even if the drip pan has been plumbed to the floor drain, some water will remain inside and evaporate through the water heaters burner chamber accelerating its corrosion – use a bucket.

While performing your gas water heater maintenance procedures you may notice the TPR valve discharging water periodically by itself. There could be a couple of reasons behind it:

– A thermal expansion in a closed water system
– Faulty TPR valve

Tank gas water heater maintenance - TPR valve drippingYou can try to slightly lift and release TPR valve lever until it sets properly without leaking and operates freely (repeat that a few times if necessary). If that doesn’t help: Turn off the gas valve, turn off the water shutoff valve, open a faucet located below the TPR valve level to release the water pressure, and contact your plumbing contractor.

DO NOT plug the TPR valve / its discharge pipe outlet to stop the leak! This could result in an explosion of your water heater!

If you have an older water heater and there’s no way of knowing if its TPR valve was ever tested, it is possible that it may still leak when re-closed after opening / testing. It’s a good idea to have your phone nearby and a plumber’s number ready… just in case.

Tank gas water heater maintenance schedule Part 2 – tank drainage / a few quarts monthly

Tank gas water heater maintenance - tank drainage - if it is an older WH tank, you may not be able to fully close the drain valve after testingThe same rule concerning older water heaters applies for the water heater drain valve maintenance procedure – if it is an older WH tank, you may not be able to fully close the drain valve after testing.

Manufacturers suggest draining a few quarts of water from the water heater’s tank once a month in order to remove silt and sediment that tend to accumulate at its base. You can perform this easy water heater maintenance procedure by attaching a garden hose to the drain valve or by using a bucket. Remember to fully open the valve, which will help in accumulated mineral deposits release.

Skipping this gas water heater maintenance procedure for a few months or even years (depending on your water’s source and quality) could allow a significant amount of mineral deposits to accumulate and harden. As a result, they could cover the WH’s gas control (thermostat) sensors, causing their erratic operation / malfunctioning.

This could further result in false temperature readouts delivered from the sensors to the gas control valve, and increased water temperature at the fixtures / higher than the gas control (thermostat) dial setting.

Tank gas water heater maintenance schedule Part 2 – Internal flue-way & venting system / annually

Tank gas water heater maintenance shut downTank gas water heater maintenance - thermostat exampleTurn the temperature dial to vacation, or the lowest setting, or to OFF position (depending on the design) and the gas cock knob to OFF position (not all designs  have one).

If the pilot stays ON, turn OFF the gas shutoff valve and call the plumber!

Wait until the water heater’s draft hood and its vent pipe have cooled down / use  protective gloves for this water heater maintenance procedure.

Tank gas water heater flue baffle hanging inside the WH flueTank gas water heater maintenance - flue baffle should be ispected on annual basisTank gas water heater maintenance - flue baffle hanger-bracketThe water heater’s internal flue requires annual inspections. In order to perform this gas water heater maintenance task, the draft hood and the vent pipe section must be disassembled, and the flue baffle removed from the flue-way for evaluation.

When replacing the flue baffle, make sure it is secured properly by its hanger at the top of the flue way. Reconnect / secure in place the vent pipe and the draft hood. Check this post for the vent pipe information.

If your gas water heater maintenance evaluation of the flue-way revealed any soot or deterioration, contact your local gas utility company or a plumber to further investigate and correct this condition prior to activating the water heater.

Test for exhaust gases spillage around the draft hood after about 5 minutes of burner operation. Put a flame of a match or candle or smoke next to the draft hood – make sure that the flame or smoke is being pulled into the draft hood. Call the plumber if it doesn’t!

Gas tank water heater & vent pipe maintenance

There are many requirements that have to be fulfilled for the gas water heater venting system to operate safely and a few components of this system that must interact with each other constantly. Once you familiarize yourself with them, importance of the gas water heater vent pipe maintenance will become very clear.

As a part of tank gas water heater maintenance have the gas water heater vent pipe inspected by a professional annually. After the first inspection /based on the design and condition of your particular installation he should be able to give you a list of basic maintenance procedures.

For details about the gas water heater venting system visit the following articles:

For details about the power vent water heater system visit  Water heater power vent and follow the maintenance task described below

  • Check all visible / accessible connections on the gas water heater power vent system PVC vent pipe starting from the power vent assembly connection – all of them must be air tight.
  • Check accessible, horizontal PVC vent pipe sections for proper support – there should be no sagging.
  • Water heater power vent motor has sealed bearings and does not require oiling. If it becomes unusually noisy – contact its manufacturer if still under warranty.

Continue to the final Tank Gas Water Heater Maintenance Part 3

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Gas Water Heater Maintenance 1 | How To Maintain Tank Water Heaters https://www.checkthishouse.com/6043/gas-water-heater-maintenance-tank-water-heaters.html Sat, 16 Apr 2011 03:53:59 +0000 http://checkthishouse.com/?p=6043 Gas Water Heater Maintenance – Part 1 of 3
Water Heater Maintenance
Part 1
Water Heater Maintenance
Part 2
Water Heater Maintenance
Part 3


Wow, I’m very impressed… You must be one of the very few that are actually interested in a gas water heater maintenance. While performing home inspections, I have asked hundreds of homeowners about this simple procedure and a raised eye brow was usually the answer to my question.

Besides water heater maintenance you can also check this water heater inspection post that covers many other things,

With a few simple gas water heater maintenance steps you can get years of reliable operation from your appliance. Most of those steps can be easily performed by a homeowner, however, there are a few that should be carried out by a qualified service personnel experienced in gas water heater repair.

Warning:
Just like with every appliance, your gas water heater maintenance should be performed on regular basis. Neglecting this requirement can compromise the proper operation of your appliance. The outcome could be hazardous, result in Carbon Monoxide poisoning and hot water scalding.

I divided this gas water heater maintenance schedule into 3 parts just in case you don’t like to scroll too much. I highly recommend to read all of them but you can use quick links below to jump between them as well.

Gas water heater maintenance components that are recommended to be periodically evaluated by a professional (even that most of them can have basic tests performed by a homeowner as well):

  • Gas control (thermostat) – annually
  • Burner in a sealed combustion chamber equipped appliances – newer water heaters (2003 and later) – bi-annually
  • TPR valve – temperature & pressure relief valve – at least once a year
  • Internal flue-way – annually
  • Venting system – annually


Gas water heater maintenance components that are suggested for routine checkups performed by a homeowner:

Part 1 – you are here

  • Visual ONLY evaluation of a burner in a sealed combustion chamber equipped appliances – newer water heaters (2003 and later) – scroll down for more
  • Open combustion chamber burner maintenance – scroll down for more

Part 2 – Tank Gas Water Heater Maintenance

  • TPR valve (temperature & pressure relief valve) maintenance – can be tested by a homeowner following simple guidelines in Part 2
  • Water heater’s tank drainage – monthly
  • Internal flue-way in a natural draft water heaters annually
  • Water heater natural draft venting system maintenance – annually / partial evaluation by a homeowner can be performed
  • Gas water heater power vent system maintenance – annually / partial evaluation by a homeowner can be performed

Part 3 – Gas Water Heater Maintenance

  • Sacrificial anode rod maintenance
  • Vacation and extended shut-down of the water heater
  • Water heater’s combustion air – extremely important!

Gas water heater maintenance – sealed combustion chamber burner, visual evaluation ONLY – perform twice a year

  1. Look through the sight glass and inspect the pilot burner flame with the main burner off and the main burner Gas water heater maintenance  - examine sealed combustion chamber through the sight glasswhile firing. To activate the burner run your hot water faucet(s) for a few minutes or increase the temperature setting – remember to return dial to the original position after testing (120°F starting point is recommended).
  2. If you observe soot buildup inside the burner chamber or / and dominating yellow – orange flame, the water heater should be turned OFF and serviced by a licensed professional.
  3. If you observe any foreign objects inside the burner chamber (other than the burner and the pilot / ignition device) have it serviced by a professional ASAP

Gas Water Heater Maintenance CAUTION:
Servicing of the water heater burner contained within the sealed combustion chamber must be performed by a licensed / qualified professional. After removing the burner’s access door, its gasket must be replaced.

Gas water heater maintenance – open combustion chamber burner – perform twice a year

Gas water heater maintenance - remove both burner chamber covers for interior evaluationRemove the burner chamber covers (be careful – they may be HOT) and observe the pilot flame with the main burner off and with the main burner while firing. The only difference from the sealed combustion chamber evaluation is that you should not look into the chamber while attempting to ignite the burner!

Wait until the WH burner is on (after running hot water for a while or increasing the temperature setting) and then look inside (use safety glasses), while keeping a safe distance to prevent an injury from heat.

Malfunctioning, improperly adjusted open burner chamber water heaters may cause a flame roll-out while firing, so be careful – call a professional if something like that happens. The burner flame should light smoothly from the pilot or igniter.

Other conditions to look for inside the burner chamber while performing gas water heater maintenance:

Gas water heater maintenance - remove rust flakes from the burner and the floor shield beneath itGas water heater maintenance - leaking water heater requires immediate servicing

  • Foreign objects on top of the burner and underneath it – the only thing you should see inside the burner chamber is the burner and the pilot / igniter

  • Corrosion / rust flakes – they are not uncommon but should be carefully removed ASAP
  • Standing or dripping water – condensation is normal, especially after running hot water for a long time. However, if it doesn’t evaporate and keeps accumulating at the base of your water heater; turn off the gas shutoff valve, turn off the water shutoff valve and call the plumber.

Gas water heater maintenance / cleaning burner chamber components – follow this procedure:

  1. Turn the temperature dial to vacation setting and the pilot knob to OFF position. If the pilot stays ON, turn OFF the gas shutoff valve and call the plumber!
  2. Make sure that the water heater’s chamber interior is cool enough to perform cleaning. A vacuum cleaner attachment can be used to remove rust flakes from the burner and the floor shield beneath it. Be extremely careful around the pilot area / igniter device – some designs are very delicate and easy to damage.
  3. Any larger objects will have to be removed by hand (use safety gloves for that). Some objects you can expect (I’ve seen them all) are birds, mice, rats, and corroded flue baffle.

Gas water heater maintenance - flue baffleA flue baffle (more about it in “Gas water heater maintenance 2”) is normally suspended inside the flue, directly above the burner. After its hooks / brackets or bottom sections corrode, deteriorate, they may fall down onto the burner in which case the flue baffle requires immediate servicing / replacement – it’s a SAFETY HAZARD – call a plumber.

Please continue to Gas Tank Water Heater Maintenance Part 2 that covers TPR valve, water heater tank drainage and internal flu-way maintenance. Remember to go over all 3 Parts of the gas water heater maintenance procedures.

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Garage Gas Water Heater Installation Requirements & How To https://www.checkthishouse.com/5712/garage-gas-hot-water-heater-raised-above-the-floor-fvir-safety.html Fri, 08 Oct 2010 18:30:50 +0000 http://checkthishouse.com/?p=5712 garage gas water heaterThe following are the general requirements for the garage gas water heater installation concerning its burner chamber height above the floor surface. Depending on the model / type / age of your particular water heater and your jurisdiction, they may or may not apply – always check before the installation. If there’s no manual explaining the garage gas water heater installation requirements, contact the manufacturer and ask for  instructions for your particular model (in many cases you’ll be able to obtain it online).]]> garage gas water heater

Garage gas water heater installation requirements

The following are the general requirements for the garage gas water heater installation concerning its burner chamber height above the floor surface. Depending on the model / type / age of your particular water heater and your jurisdiction, they may or may not apply – always check before the installation.

If there’s no manual explaining the garage gas water heater installation requirements, contact the manufacturer and ask for instructions for your particular model (in many cases you’ll be able to obtain it online).

However, the rules listed below are extremely important. If they do apply to your garage gas water heater, you may be putting your life in danger by not following them.

As a general requirement, you should not install a gas water heater in any location where gasoline, flammable vapors or liquids, and combustible materials are likely to be present. Such installation may result in an explosion or fire, but sometimes there may be no other choices. If this is where you’re standing right now, you must follow the garage gas water heater installation rules.

1. How high should the garage gas water heater be raised off of the floor?

The free-standing or attached garage gas water heater installation is one of those not-preferable locations, but sometimes it is the only one.

Water heater installed in a closet opening to the garage

Ignition source (pilot, electronic igniter, hot surface igniter, etc.) of the garage gas water heater must be 18″ from the floor surface.
The same rule applies to the gas water heater that has been installed in a room opening to the garage, such as a utility closet, or utility room. This applies even if the door(s) separating the garage and the water heater room are air tight / self closing.

2. Water heater ignition source must be 18″ from the floor in an area where flammables are stored.

For the garage gas water heater and any area that is also dedicated to storing flammables, or if there’s a possibility of such materials being stored there, put the appliance on a platform so the ignition source is at least 18” above the floor surface. Make sure that this platform is capable of supporting the weight of the filled WH.
Open combustion chamber water heater and flammable liquids stored in front of itThe way it often works in our homes is that while looking for some storage space we stuff our utility room / closet with everything that doesn’t fit anywhere else. Things such as leftover paint, paint thinner, all kinds of cleaning chemicals, container filled with emergency gasoline, etc are usually found here. Is this how your water heater closet looks? Well, you’re not alone.

Sealed combustion chamber water heaterBesides accidental spillage, some of those plastic containers may simply melt down while standing next to the water heater or on top of it, spilling its contents, and causing vapors to ignite underneath the water heater and inside the burner chamber – go and look around your WH base. Don’t push it to the side! Take it out of there!

Bad news: most of the WH manufactured prior to 2003 had an open combustion chamber and they were not equipped with a safety device that would prevent vapor ignition.

Good news / also applies to garage gas water heater installations

  • Effective July 1, 2003, all residential 30, 40, and 50 gallon atmospheric vent (natural draft) water heaters are required to be equipped with FVIR -flammable vapor ignition resistant design.
  • July 1, 2006 – the same requirement has been applied to 30, 40, and 50 gallon power-vented residential gas water heaters with less than 75,000 BTU input.
  • July 1,  2007 – water heater conversion to FVIR design has been extended to all residential water heaters with inputs of 75 000 BTU’s or less including Power Direct-Vent, Direct-Vent, Manufactured Housing and larger gallon capacity models not covered in the first two phases.

3. Elevation of the garage gas water heater above the floor is not required if the water heater is FVIR -flammable vapor ignition resistant.

Garage gas water heater elevated 18 inches above the floorTheoretically, FVIR feature-equipped garage gas water heater could be installed without the previously required 18” elevation (wherever the flammables are stored). The new water heaters have a sealed combustion / burner chamber and a push-button igniter mounted on the exterior.  Although they still draw the combustion air from the surrounding area, safeguards incorporated into this new design prevent gas or vapors ignited inside the chamber from escaping into the room.

I said that “theoretically” you can skip the 18” elevation requirement, because manufacturers and some jurisdictions may still recommend (or require) that even garage gas water heaters equipped with FVIR are still installed 18 inches above the floor surface.

Always read the manual and verify procedures with your local code enforcement division before the garage gas water heater installation… any water heater installation – it could save you time and money.

Water heater on the ground installation requires 3 inch pedestal4. Gas water heater On-the-Ground installation

Water heater requires a 3” pedestal (concrete, etc.) to minimize moisture infiltration / corrosion. It cannot be installed directly on-the-ground.

5. Gas water heaters on combustible floor

For the garage gas water heater installations this would most likely apply to platform materials. Water heaters can be installed directly / without elevation on a combustible floor (unless otherwise specified in its manual or by your local jurisdiction), except on carpeting. If it must be installed on carpeting, you need to place a wood or metal panel beneath the water heater, extending at least 3” beyond its base in all directions.

6. Electric water heater in a garage

Some jurisdictions may require electric water heaters to be elevated above the garage floor as well. Because of the location of the lower heating element, an electric WH may have to be raised 10 to 12 inches off the floor – check first!

7. Water heater installed in the garage requires protective guards / bollards in order to prevent a car from driving into it.

How about garage gas water heater maintenance…  it will extend its life span and make your life safer.

That covers the basics of the garage gas water heater installation concerning its burner chamber height above the floor surface.

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Furnace, Water Heater & Vent Pipe Clearance Guides & Locations https://www.checkthishouse.com/3151/furnace-water-heater-vent-pipe-clearances-and-locations.html Sat, 07 Mar 2009 03:25:02 +0000 http://checkthishouse.com/?p=3151 furnace, hot water tank clearance locationsGas burning appliances vent pipes produce heat when discharging exhaust gases to exterior. Temperature of the vent pipe is transferred to the surrounding area and all the materials that are in the vent pipe vicinity. Problems start arising if those materials are combustible and located to close to the furnace, water heater vent pipe. If you apply heat to a combustible material for some period of time (that varies between materials), its point of ignition will gradually get lower and eventually little heat will be required to start a fire – that’s why you need a clearance between the vent pipe and a combustible material.]]> furnace, hot water tank clearance locations

Vent pipe clearance to combustible materials

Visit water heater inspection for more information about this subject.

Vent pipe clearances - single wall vent pipe not permitted in attic, too close to framing - 6 inches minimum distance to combustiblesFurnace, water heater vent pipe clearance - paper and wood framing are highly flammable and require 6 inch clearance to a single wall vent pipeFurnace and water heater vent pipes require clearance to combustible materials – why is that necessary?

Gas burning appliances vent pipes produce heat when discharging exhaust gases to exterior.

Temperature of the vent pipe is transferred to the surrounding area and all the materials that are in the vent pipe vicinity. Problems start arising if those materials are combustible and located to close to the furnace, water heater vent pipe.

Furnace, water heater vent pipe clearances - single wall vent pipe installed too close to the main beamIf you apply heat to a combustible material for some period of time (that varies between materials), its point of ignition will gradually get lower and eventually little heat will be required to start a fire – that’s why you need a clearance between the vent pipe and a combustible material.

Flash point / temperature at which wood will ignite is 572F (300C).

For all of us not aware of this condition, here are the required / minimum furnace, water heater vent pipe clearances and locations where the single or double wall vent pipes can be installed.

Furnace / water heater vent pipe clearance – single wall

Furnace, water heater vent pipe clearances - single wall vent pipe requires 6 inches clearance from the floor framing

Minimum distance between the single wall vent pipe and combustible materials is 6”

The minimum distance between the single wall vent pipe and combustible materials is 6”

The single wall vent pipe cannot be concealed inside the wall or floor. Even if you keep the clearances at the entrance and exit from that space, whatever section is inside must be double wall type pipe.

A vent pipe is an important part of the gas water heater maintenance – don’t forget your schedule.Furnace, water heater vent pipe clearances - single wall cannot penetrate ceiling, wall or floorFurnace, water heater vent pipe clearances - no single wall can enter ceiling, wall or floorThe reasoning is simple – you can’t see what is happening inside the wall or floor, and if the single wall vent pipe starts corroding, separates, leaks exhaust gases, you’ll have no control over it. Also, concealed spaces have no way of discharging heat and 6” vent pipe clearance simply wouldn’t help.

Furnace, water heater vent pipe clearance - single wall vent pipe is not permitted in unconditioned atticFurnace, water heater vent pipe clearances - no single wall furnace vent pipe is permitted in an unconditioned attic The furnace, water heater single wall vent pipe cannot start in or pass through the attic. Also, it cannot be used in the crawlspace or other unconditioned space. The exceptions are unconditioned basements and garages within the exterior walls if local 99% winter design temperature equals or is larger than 5F.

Winter design temperature is the temperature that is exceeded during either 99% or 97.5% of the hours in December, January and February. Heating systems through the US are designed / calculated based on winter design temperature. 97.5% winter design temperature values are typically used by local codes. (Simplified Design of HVAC systems by William Bobenhausen)

Furnace, water heater vent pipe clearances - single wall pipe thimble at ceiling penetration, but double wall pipe is requiredA conditioned space is an area where temperature and humidity are controlled directly or indirectly.
An unconditioned space is an area isolated with doors and / or partitions from a conditioned space.

Typical examples of an unconditioned space are unheated attics, crawl spaces or garages.

  • Whenever the single wall vent pipe penetrates the roof surface, it requires thimble which must extend 18” above and 6” below the surface. Thimble must be open at the bottom and sealed around the vent pipe above the roof.
  • Horizontal section of the furnace, water heater single wall vent pipe cannot be longer than 75% of the vertical vent pipe length

Furnace, water heater vent pipe clearance – double wall

  • Typical listed and labeled double wall vent pipe clearance to combustible materials is one inch, but you should always check before installation.
  • Maximum horizontal section of the furnace, water heater double wall vent pipe cannot be longer than 100% of the vertical vent pipe length.

It will complete the information about the furnace and the water heater vent pipe clearance requirements.

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Gas Water Heater PVC Vent Pipe and WH Power Vent https://www.checkthishouse.com/2991/water-heater-pvc-vent-pipe-and-power-venting.html Sat, 21 Feb 2009 05:04:26 +0000 http://checkthishouse.com/?p=2991 The following information does not apply to a tankless type water heater power vent systems. PVC vent pipes can be used only with water heater power vent /exhaust motor equipped hot water heaters also known as an induced draft gas water heaters. The following information may also apply to CPVC and ABS pipes if such installations ... Read more]]>

The following information does not apply to a tankless type water heater power vent systems.

Water Heater PVC Vent Pipe - induced draft ventingWater heater power vent PVC pipe - induced draft venting 2Water Heater PVC Vent Pipe - induced draft venting 3

PVC vent pipes can be used only with water heater power vent /exhaust motor equipped hot water heaters also known as an induced draft gas water heaters.

The following information may also apply to CPVC and ABS pipes if such installations are permitted by the manufacturer and local authorities. Check water heater inspection for more information about water heater installations.

For the rest of this post I’ll be using “PVC vent pipe” just to make it easier. When installing a new or altering your existing water heater vent pipe installation, always check your particular water heater model for the manufacturer requirements and verify installation with local jurisdiction authorities.

There are two types of PVC pipe water heater power vent systems – single (single wall and concentric) and double pipe.

PVC vent pipe water heater power vent system (single wall PVC)

Power vent equipped water heater discharges exhaust gases through that single pipe. However, requires combustion air for fuel burning process and this must be supplied in sufficient amounts from the house interior or exterior.

You cannot install the water heater power vent system that uses just a single wall PVC vent pipe for exhaust discharge purposes in a closet, behind the solid doors, with no air supplying vents,  or in any type of room that doesn’t conform to the combustion air requirements for fuel burning appliances.

Inadequate amount of air will cause incomplete combustion, and one of the bi-products of that is Carbon Monoxide, which could be deadly.

There are also single-concentric water heater power vent / PVC vent pipe systems used by a high efficiency and high efficiency condensing storage / tank type water heaters. They have combustion air supplied from the exterior (some water heater PVC vent pipe systems might be 2 pipes starting at the water heater and converted into one concentric pipe before wall / roof penetration).

PVC vent pipe water heater power vent system based on 2 pipes

This system is called direct vent, uses one PVC pipe to supply combustion air from the house exterior and second PVC vent pipe to discharge exhaust gases beyond the house. Both PVC vent pipes MUST terminate on the outside.
Advantage of the 2 PVC pipe water heater venting system (and a concentric / single pipe), is that you can install this type of the water heater power vented system in the closet / behind the solid door, or crawlspace with no vents, etc.

Water heater power vent systems utilizing double PVC vent pipe also come in high efficiency and condensing high efficiency “flavors”.

PVC vent pipe water heater power vent system cannot be connected to the regular chimney or share venting with other appliance (e.g. water heater power vent and a high efficiency furnace cannot be venting through the single PVC pipe)

Types and sizes of pipes that can be used in water heater power vent systems

Water heater power vent PVC pipe - SCH 40 PVC, CPVC and ABS pipes are used for ventingTypical water heater power vent equipped system utilizes (unless otherwise specified by the manufacturer and/or by your local jurisdiction) 2″, 3″ or 4″ diameter, schedule 40 PVC, CPVC or ABS pipe. Size of the vent pipe depends on model, BTU rating of your appliance, length of the entire horizontal and vertical pipe section, and the number of installed elbows.

Example (based on A.O. Smith Water Heater Power Vent requirements):

GPVH-40 and GPVH-50 model (40 and 50 gal / 40,000 and 50,000 BTU) water heaters.

Max water heater PVC vent pipe length would be:

  • 40’ for 2” pipe
  • 120’ for 3” pipe
  • 160’ for 4” pipe

However, for every installed 2”&3” elbow you have to deduct 5’ from the maximum distance, and for a 4” elbow – 8’ of the pipe.

Water heater PVC vent pipe clearances at side wall penetrationWater heater power vent PVC pipe connections must be air tightWater heater PVC vent pipe roof clearancesAlways check water heater power vent system PVC vent pipe requirements that apply to your particular model. If you are missing the water heater PVC vent system installation manual, contact the appliance’s manufacturer / check online if possible.

  • Gas water heater power vent / induced draft gas water heater PVC pipe can be installed vertically (through the roof) and horizontally (through the wall). For horizontal installations is should be supported every 3’ – 3 ½” to avoid sagging along the run (or per manufacturer’s instructions).
  • All connections on the gas water heater power vent system PVC vent pipe must be air tight (require primer and cement for PVC/CPVC/ABS pipe)
  • Slope of the pipe – always check manual, but for non-condensing installations (not high-efficiency water heater) level or slightly up-slope towards the exterior should be OK.

Gas water heater power vent / induced draft gas water heater PVC pipe exterior terminations

Again check the manual, but some of the most common water heater power vent PVC pipe requirements are:

  • Horizontal exhaust outlet 12” minimum above the ground or expected snow level (for cold climates)
  • Vent riser – 24”(if pipe penetrates the wall lower that 12” from the ground)
  • Minimum 18” above the highest point where it penetrates the roof
  • Minimum 6” away from the vertical wall
  • Exhaust pointing down with rodent screen at the end
  • min 36″ above the forced air inlet if closer than 120″ horizontally to the inlet
  • min 9″ -12″ from the window / door opening (depending on BTU rating)

Below are links to some of the manuals available online showing different types of water heater power vent installations.

Did gas water heater maintenance ever cross your mind? It’s very important for your safety and to maximize your appliance’s performance.

Feel free to ask if you have any questions about the gas water heater power vent system and water heater PVC vent pipe.

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Combustion Air for Fuel Burning Appliances https://www.checkthishouse.com/2531/combustion-air-for-fuel-burning-appliances.html Fri, 23 Jan 2009 05:23:28 +0000 http://checkthishouse.com/?p=2531 Combustion air is required for all types of fuel burning appliances in our homes to properly burn that fuel.

Combustion air has three functions:

  1. It  is required to properly burn fuel
  2. To dilute exhaust gases that are being vented to exterior
  3. To vent and cool appliances

The most popular fuel used in our homes is of course natural gas.

For every one cubic foot of gas, there are 10 cubic feet of combustion air needed for clean burning in addition to dilution and ventilation air.

There are two products out of a perfectly balanced gas combustion – carbon dioxide and water vapor, which are perfectly safe. However, if we limit the amount of the combustion air in the process,  a third bi-product might develop, unfortunately a deadly one – Carbon Monoxide.

Example:

Imagine a gas water heater in a small closet, behind the solid door, and without any openings in walls providing that necessary combustion air. After using all of the closet’s combustion air for burning process, the air pressure in the closet will become lower than the one inside the water heater’s vent flue pipe.

The water heater closet will pretty much act now like a vacuum and the exhaust gases may be sucked back into the closet space instead of being discharged to the exterior. Since the oxygen starving combustion process is now producing that deadly Carbon Monoxide, it will eventually leak through the gaps around the closet door into the house…

The areas designated for fuel burning appliances are described as confined space and un-confined space.

The water heater closet from my example could be a confined space – an area with a closed, solid door and walls / ceiling that create a barrier between the appliance and the rest of the house, thus not allowing any combustion air penetration.

A confined space is a room that has less than 50 cubic ft of air volume for every 1000 BTU/hr of appliance input .

Combustion air amount depends on the appliances BTU's

If the water heater has a 40 000 BTU/hr rating, the room would have to have over 2000 cubic feet of volume to provide enough combustion air (without additional sources) for proper burning process.

Un-confined space is a room that has more than 50 cubic ft of air volume for every 1000 BTU/hr of appliance input (BTU/hr input should be on the appliance label / information tag).

Assuming that our example water heater closet itself is a confined space, and it is located in a room being an un-confined space, we would require two openings in the closet door or wall to allow combustion air inside. One opening should be located within 12” from the floor, and second within 12” from the ceiling of the enclosure.

Combustion air ports in the utility room wallOpenings between confined space and unconfined space must have at least 100 sq. inch area each and provide at least 1sq. inch of a free airflow area per 1000 BTU/hr of the appliance input (1/4” min. or larger mesh screen if installed over the openings, metal grills and louvers provide 60%-75% of their net free area, wood louvers only 20%-25%).

With a 40000 BTU/hr water heater input, the combustion process would require only 40 sq. inches of an opening at top and bottom, but you still have to obey the minimum 100 sq. inches per each opening requirement.

Examples of combustion air opening sizes between confined space and un-confined space (inside of the house air)

Up to 100K BTU/hr – 100 square inch openings
125K BTU/hr – 125 square inch openings
150K BTU/hr – 150 square inch openings
175K BTU/hr – 175 square inch openings, and so-forth

Click for house interior combustion air calculations.

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Gas Water Heater and Furnace Chimney Flue Size Calculations https://www.checkthishouse.com/1887/gas-water-heater-and-furnace-chimney-flue-sizing.html Tue, 18 Nov 2008 03:55:13 +0000 http://checkthishouse.com/?p=1887 Furnace Chimney Flue Size CalculationsChimney Flue Size Calculations The following gas water heater and furnace chimney flue size calculations are based on Peoples Gas “Construction Guide for Gas Usage” in the city of Chicago and National Fuel Gas Code. Before applying any of the following rules, you must check your local building code requirements, and appliance manufacturer installation instruction. Have you checked your house brick chimney lately… or whatever type of the chimney you have? Did you have a new furnace or water heater installed / was your house chimney flue recalculated for those new appliances? Make sure that you chimney flue size / diameter is correct; [...]]]> Furnace Chimney Flue Size Calculations

The following gas water heater and furnace chimney flue size calculations are based on Peoples Gas “Construction Guide for Gas Usage” in the city of Chicago and National Fuel Gas Code. Before applying any of the following rules, you must check your local building code requirements, and appliance manufacturer installation instruction.

Chimney flue size - diameter must be properly calculated and installed - it is a serious safety issue!

  • Have you checked your house brick chimney lately… or whatever type of the chimney you have?
  • Did you have a new furnace or water heater installed / was your house chimney flue recalculated for those new appliances?

Make sure that you chimney flue size / diameter is correct; chimney flue size is one of the parameters that will help to achieve proper draft – the water heater and a furnace exhaust gases will be discharged safely to the house exterior – your life may depend on it. Some of the consequences of an excessive or insufficient chimney draft are:

  • Poor burner performance
  • Excessive combustion (burning process) noise
  • Improper combustion which could result in Carbon Monoxide spillage into the living area
  • Soot buildup inside and around the burner chamber of your appliances

The basic method for the chimney flue size calculations is “The Seven Times Rule” (applies to natural draft and / or fan assisted type appliances vented into the same chimney).

When two or more appliances are connected to a chimney, the flow area of the largest section of that chimney cannot exceed seven times the smallest flue collar, or draft hood outlet area, unless designed with approved engineering methods.

To make it simple – if you have a gas water heater with a 3” draft hood, and a furnace with a 4” flue collar connected to the same chimney flue, you’d calculate that chimney flue size based on the 3” draft hood – the smaller of two. So let’s calculate… or why don’t we skip those calculations and I’ll give you the answers:

The largest permissible flow area (in²) of the chimney flue for draft hoods or flue collars.
Diameter of Draft Hood Outlet or Flue Collar Flow Area (in²)
3″ 7.065
4″ 12.560
5″ 19.625
6″ 28.260
7″ 38.465

The Seven Times Rule application results:

The Seven Times Rule for appliances connected to a multistory common chimney
Smallest draft hood outlet or flue collar Largest section of vertical vent or chimney
3″ 7″
4″ 10″
5″ 13″
6″ 15″
7″ 18″

Q. Are those numbers sufficient for calculating you chimney flue size / diameter?

A. No, they aren’t! There are several other factors responsible for chimney flue size; chimney placement, height, lateral length of the vent pipe, type of the vent pipe, number and type of the connectors along the entire chimney flue run, size and category of the vented appliances…

So it’s always smart to have a professional calculating your chimney flue size. But, using the tables above will at least prevent many wild, way off the chart installations. Make sure that you have Carbon Monoxide detector installation performed according your local jurisdiction requirements!

If you’re looking for a gas water heater and furnace chimney flue size tables / guides covering most of the possibilities, try this publication by Hart & Cooley.

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Chimney Flue Requirements, Furnace and Water Heater Venting https://www.checkthishouse.com/72/chimney-flue-furnace-water-heater-venting.html Fri, 20 Jun 2008 18:07:44 +0000 http://checkthishouse.com/?p=128 Chimney Flue RequirementsProper furnace / water heater venting is an extremely important issue, which depends on the performance of the house chimney / chimney flue or other exhaust assemblies. The conditions explained in this post also apply to the wood burning appliances. Consequences of improperly assembled vent pipes, problematic chimney flue, deteriorating chimney walls can be sometimes fatal – fire and Carbon Monoxide poisoning are topping the list. Therefore, combustion products from your furnace, water heater, wood burning fireplace, and any other appliance that requires some kind of an exterior vent / chimney, have to be properly properly discharged to the exterior. Certain requirements [...]]]> Chimney Flue Requirements

Proper furnace / water heater venting is an extremely important issue, which depends on the performance of the house chimney / chimney flue or other exhaust assemblies. The conditions explained in this post also apply to the wood burning appliances.

Consequences of improperly assembled vent pipes, problematic chimney flue, deteriorating chimney walls can be sometimes fatal – fire and Carbon Monoxide poisoning are topping the list.

Therefore, combustion products from your furnace, water heater, wood-burning fireplace, and any other appliance that requires some kind of an exterior vent / chimney, have to be properly properly discharged to the exterior through its flue.

Certain requirements have to be met for the appliance’s chimney / chimney flue to draft properly. The most obvious one is unobstructed surroundings, in particular the roof itself. Depending on chimney placement / distance to the surrounding walls, there are different height rules.

For oil and wood burning appliances there is a very simple formula that regulates this chimney height requirement, it is called “3-foot, 2-foot, 10-foot rule”. What it means is that top of the chimney should be 3 feet above the roof surface through which it protrudes and 2 feet above anything within a 10′ radius measured horizontally (those are minimums).

This chimney rule can be applied to wood burning fireplaces, heating stoves and any oil fueled appliances, but remember that manufacturer requirements have to be incorporated into it.

Improperly installed water heater chimney / ventFor gas venting appliances, the chimney flue / venting rules are more complex, simply because of the variety of products on the market. For a double wall type vent (required in cold climates) I’ve prepared a separate post – Gas appliance vent terminations.

Below are some requirements for the furnace / water heater single wall vent pipe / chimney (warm climate):

  • Chimney / chimney flue must terminate min. 2′ above the roof
  • Chimney / chimney flue must terminate min. 2′ higher than building withing 10′
  • Chimney / chimney flue must terminate min. 5′ above the flue collar (e.g. water heater installed close to the roof framing would need at least 5′ long vertical vent pipe)
  • Single wall vent pipe requires minimum 6″ of clearance to combustible materials

General rule –  the chimney should not be outside a window or other house opening.

There’s several other requirements which apply to certain types of furnaces and water heaters venting. Always follow manufacturer guidelines, if you have any concerns about your chimney, call a heating contractor or other chimney specialist and have the chimney/heating system examined.

Never connect bathroom vent to the chimney flueSingle chimney with two flues, one for wood burning fireplace, second for gas appliances1. NEVER USE CHIMNEY FLUE TO VENT CLOTHES DRYER, KITCHEN / BATHROOM VENT

2. DO NOT USE SINGLE CHIMNEY FLUE TO VENT GAS AND SOLID FUEL (WOOD BURNING FIREPLACE OR HEATING STOVE) – you can have one chimney but multiple flues for different fuel types

3. READ MANUFACTURER’S INSTALLATION GUIDE and ask your licensed HVAC or plumbing contractor / installer if you have any concerns – installation guides are usually very clear, with simple diagrams explaining all required clearances, type of required materials, etc.

Chimney flue diameter downsized with new metal liner pipe4. If you’re replacing an old water heater (check water heater inspection) and a furnace (or any combination of those), with new appliances that also require regular chimney, make sure that your chimney flue is evaluated. Flue gases temperature in older, low efficiency furnaces (78% and less efficient), was sufficient to elevate chimney flue temperature to the point which guaranteed proper draft.

When connecting a new, regular type (known as category 1 type gas appliances) furnace /water heater, with efficiency slightly below 83%, old chimney flue size might need to be decreased with a new liner. This is extremely important, and serves various purposes – properly sized chimney flue:

  • prevents acidic condensate from forming on the furnace / water heater chimney flue walls
  • colder gases in large size chimney flue will not have enough energy to travel all the way to the  top and discharge safely beyond the property (becomes critical during cold season), they will condensate on cold chimney flue walls, cause deterioration and corrosion of appliance metal vent pipes
  • allows furnace / water heater combustion process gases to draft efficiently beyond the property
  • prevents flue gases from returning into the house, which would create potentially hazardous conditions, possibility of Carbon Monoxide poisoning

5. If one appliance has been disconnected from the chimney previously serving 2 or more appliances, make sure that a professional re-evaluates your chimney flue. It may need to be down-sized to prevent flue gas condensation and to provide proper draft (typical condition when upgrading to a high efficiency furnace) – check this chimney flue sizing guide.

This video below explains in detail how to install a new liner inside the chimney. It is 8 minutes long, but you’ll get a good idea about the entire procedure – this is an extremely important and often necessary procedure.

 

Water heater improperly connected to chimney flue with T type connector - not permitted when induced / forced draft motor appliance connected to the same flue as natural draft applianceFurnace and water heater properly connected to chimney flue with WYE type connector6. If you’re replacing natural draft furnace (no motor assistance for exhaust gases removal), with an induced / forced draft motor equipped appliance, and your natural draft water heater remains connected to the same chimney flue pipe, make sure that water heater vent pipe connection is “Y”, and not “T” type.

“Y” type vent pipes connection is necessary to prevent exhaust gases from mechanical draft type appliance vent pipe, from being pushed back into the natural draft type vent pipe, and contaminate living space.

Possibility of such contamination is greater during the cold season and on taller, exposed chimney / for example – attached to the side wall of the house. Before the hot exhaust gases warm up the chimney flue and create proper draft, they often discharge through the water heater’s draft hood.

Broken seal on high efficiency furnace PVC vent pipe connectionHigh efficiency PVC pipe and water heater vent pipe in the same chimney flue - not permittedHigh efficiency furnace PVC vent pipes exterior termination When upgrading to, or having a high efficiency furnace installed, exhaust gases will be discharged through the PVC pipe, and not the chimney flue.

There are two types of venting associated with those furnaces – single pipe and two pipe systems.

Because high-efficiency furnaces venting system must be air tight, PVC vent pipe connections should be monitored periodically during furnace operation for any moisture / condensation. If such occurs on PVC joints, you should have this condition evaluated by a licensed HVAC contractor – connection will have to be resealed.

PVC vent pipes should not be inserted into the chimney flue if it is still used for other appliances venting.

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House Water Heater Vent Pipe Tips & How To Do It Right https://www.checkthishouse.com/49/water-heater-vent-pipe.html https://www.checkthishouse.com/49/water-heater-vent-pipe.html#comments Wed, 19 Mar 2008 22:14:46 +0000 http://checkthishouse.com/?p=78 There’s more about the water heater vent pipe in my article below the video. Follow the links to skip down for more important information. Water heater vent pipe draft hood Water heater vent pipe material Water heater vent pipe connections Water heater vent pipe pitch Water heater vent pipe corrosion Water heater vent pipe clearances ... Read more]]>

There’s more about the water heater vent pipe in my article below the video. Follow the links to skip down for more important information.

House Water Heater Venting Video:

To fully understand house natural gas water heater venting I highly recommend reading House Brick Chimney Problems & Gas Water Heater and Furnace Chimney Flue Sizing posts – several of the water heater vent pipe conditions described below depend on properly operating and installed chimney!

Check my new post explaining tank gas water heater maintenance and water heater inspection It’s important!

There are two common natural draft gas water heater vent pipe systems:

  • natural draft gas water heater – explained below
  • induced draft / water heater PVC pipe venting / power venting

Natural draft gas water heater vent pipe system is still dominating and as long as the property has favorable structural conditions and a chimney dedicated for use with gas burning appliances, you can use this type of venting.

Typical, natural draft water heater vent pipe assembly - missing screws at draft hood connectionTypical connection of the natural draft gas water heater vent pipe would look more or less like one on the picture (one of the problems with this connection – missing screws at draft hood). There might be several variations… some good and some bad of course.

Assuming, that you don’t know anything about water heater vent pipe subject, this is how the natural draft gas water heater venting should be installed:

Water heater vent pipe draft hood

On top of natural draft gas water heater, in its center section, right above the water heater vent, you should have a draft hood installed. It sits on 3-4 short legs, sometimes secured to the water heater top plate with screws, or (depending on design) has its legs shaped like pins or hooks at the end, inserted into the holes in water heater top cover.

Water heater vent pipe - collapsed natural draft gas water heater draft hood poses safety hazardFor the gas water heater vent pipe system to operate properly its Draft Hood Has to be Centered over the vent hole, and its legs must be straight – any displaced or deformed draft hoods should be serviced / replaced if necessary. Water heater draft hoods serve a very important purpose and if not installed correctly, carbon monoxide gases may be expelled into the living space. I’m pretty sure you’re aware how dangerous Carbon Monoxide can be…

  1. Gas water heater draft hoods provide additional air for the combustion process gases, to be properly pulled out from the burner chamber (base of the water heater), into the water heater vent pipe and the chimney
  2. Gas water heater draft hoods act as a device, which in case of down-draft (a condition which forces air / wind back into the vent pipe / chimney), prevents air from extinguishing the gas burner.

Loose water heater vent pipe, oversized - requires reducing connectorGas water heater draft hoods come in different sizes, and if you are replacing water heater, make sure, that the draft hood and the water heater vent pipe match each other.

Water heater venting - installed vent pipe reducing connectorIf the draft hood that came with your water heater has a top opening diameter designed for 3″ vent pipe, and you have 4″ vent pipe installed, use an adapter / increaser to join both of them together.

Downsizing of water heater vent pipe is not permitted and poses safety hazardHowever, if the gas water heater draft hood is larger, designed for a 4″ pipe – do not downsize it! / DON’T install reducing connector from 4″ draft hood to 3″ water heater vent pipe just to accommodate an old venting system.

Water heater vent pipe and draft hood properly secured with screwsReplace the smaller size vent pipe with a proper / required size:

-most 30 gallons, 40 gallons, and 50 gallons gas water heaters use 3″ diameter vent pipe

-some 50 gallons might require 4″

-75 gallons and more will call for 4″ and more

Always follow the appliance manufacturer’s recommendations and comply with your local code requirements – again – never downsize the water heater vent pipe!

Natural draft gas water heater vent pipe material

Flexible, aluminum connector used as a water heater vent pipe is not permittedAluminum water heater vent pipe section is not permittedFood can used as a water heater vent pipe is not permitted

For natural draft type just use galvanized steel pipe and don’t experiment with aluminum pipes, food cans with removed both ends, stainless steel sections, blue stove pipes, high temperature plastic tubing, flexible pipes…, etc.

Water heater vent pipe example - developed height

Make the vent pipe section between the water heater and the chimney as short and as straight as possible. The common rule is that the horizontal part of the single wall vent pipe must be equal or shorter than 75% of it’s total developed height.

Draft hood and gas water heater vent pipe connections

The connection between the draft hood and the vent pipe should be secured with sheet metal screws – three per connection on a single wall pipe are recommended.

DO NOT use regular duct tape to secure or seal connections. Some building inspectors don’t even allow aluminum tape on joints. Simply because it hides problems like corrosion or holes developing on surface.

If you are using a B-vent which is a double wall vent pipe, you supposed to use screws on the first connection only – to the draft hood or to the single wall water heater vent pipe. Smaller diameter double wall to double wall vent pipe sections utilize twist lock fittings with no screws / larger diameter B-vent pipes might require screws on its joints.

Natural draft gas water heater vent pipe pitch

Water heater venting - WH vent pipe horizontal run / pipe has a negative pitch

Gas water heater vent pipe connector must continuously run upward towards the chimney entrance, rising not less than 1/4″ per linear foot, to provide proper draft. Some installation might be a significant challenge, or even become impossible, due to a water heater height and chimney flue connection level, in those cases, induced draft motor equipped water heater should be considered.

Natural draft gas water heater vent pipes corrosion

Heavily corroded water heater vent pipe, holes on surface might cause Carbon Monoxide spillageSeverely corroded water heater vent pipe poses safety hazard, possibility of Carbon Monoxide poisoningWater heater venting - corroded vent pipe connections might cause CO leakage and joints separation

WH vent pipes should be monitored periodically for corrosion and deterioration. Problems with proper drafting, chimney conditions and combustion air issues usually cause galvanized pipes to corrode.

Small holes start appearing on their surface – most common areas are along the bottom portion and on connectors. At some point, corroded gas water heater vent pipe wall becomes very soft, and might fall apart when under even slight pressure.

Corroding gas water heater vent pipes should be replaced as soon as possible, to prevent possibility of exhaust fumes / Carbon Monoxide contamination.

Water heater vent pipe clearances and restrictions

Gas water heater vent pipe located to close to combustible materialsSingle wall gas water heater vent pipe / connector cannot be installed closer than 6″ from any combustible materials such as floor / wall framing, paper, etc.).  Such installation could create pyrophoric conditions and a fire-hazard.

Pyrophoric condition is when a material  ignites spontaneously at significantly lower temperature if it is constantly exposed to heat. So, if something would normally ignite at 500F, by applying constant heat to it, that ignition point might be lowered to let’s say 250F – it’s just an example…

  • Single wall natural draft gas water heater vent pipe cannot be used in unheated areas like attic or garage (even if only partially penetrating that space) , because such vent pipe installation will cause excessive condensation on vent pipe walls and compromise proper drafting – double wall pipe / B-vent type is required.
  • Single wall natural draft gas water heater vent pipe can not be used inside the walls, ceilings and any inaccessible areas – double wall type vent pipe / B-vent must be installed.

Thinking about relocating your natural draft gas water heater to the garage area? Check this important information – garage water heater requirements.

Check the gas water heater vent pipe clearances post for more about natural draft water heater venting.

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Water Heater Gas Connectors & Flexible Gas Water Heater Connectors https://www.checkthishouse.com/17/water-heater-gas-supply-connector.html https://www.checkthishouse.com/17/water-heater-gas-supply-connector.html#comments Sat, 08 Mar 2008 02:30:13 +0000 http://checkthishouse.com/testhouse/?p=24 Water Heater gas connectorsWater Heater Gas Connector Illinois remained very conservative, as far as water heater gas connector type (or any other permanently installed appliance gas connection), which used to be black steel pipe only. However, according to Peoples Gas / Nicor website “Updated Construction Guide” (just fill-up the pup-up from and you’ll be able to open it) the use of CSST – corrugated stainless steel tubing, as a final gas connection for permanently installed appliances, such as water heaters, furnaces and boilers is now permitted. If you are planning to use CSST tubing as a water heater gas connector, make sure that you consult this [...]]]> Water Heater gas connectors

Illinois remained very conservative, as far as water heater gas connector type (or any other permanently installed appliance gas connection), which used to be black steel pipe only.

However, according to Peoples Gas / Nicor website “Updated Construction Guide” (just fill-up the pup-up from and you’ll be able to open it) the use of CSST – corrugated stainless steel tubing, as a final gas connection for permanently installed appliances, such as water heaters, furnaces and boilers is now permitted.

If you are planning to use CSST tubing as a water heater gas connector, make sure that you consult this installation with your local code enforcement division, and if approved, have a certified contractor perform this work. Because water heater CSST type connector installation is still rare in our state, I’ll explain a couple of most common violations associated with water heater gas connector installation.

Check this important post – Tank gas water heater maintenance

Flexible water heater gas connector

Water heater gas connector - flexible applinace type connectors are not permitted in Illinois

Appliance type flexible water heater gas connector is not a permitted type of installation in Illinois. Often, when replacing water heater, its dimensions are slightly different from the previous one, and old gas piping has to be altered, so it matches new connections.

The easiest way is to eliminate old steel pipe used as water heater gas connector and install an appliance type flexible connector. Unfortunately, if you’ll have a gas company employee visiting your house, and he’ll notice this installation, you might get a violation ticket and have a gas turned off until proper connection is established.

Water heater gas connector requires a drip leg

Drip leg missing on water heater gas connector

Drip leg / sediment trap is a required component of the water heater gas connector. Its a short piece of a pipe with a cap on the bottom visible on first image to the left (attached to the bottom of a ‘”T” connector).

Water heater gas connector / supply line drip leg is intended to capture any condensed water that may have been transported with gas, and shall be installed as close to the inlet of the water heater as practical (not required on illuminating appliances, ranges, clothes dryers, gas fireplaces and outdoor grills).

Some states might not require drip leg installation on a water heater gas connector so check with your local building department.

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What is a TPRV (Temporary Pressure Relief Valve) and Why They’re Important https://www.checkthishouse.com/16/water-heater-tpr-safety-valve.html https://www.checkthishouse.com/16/water-heater-tpr-safety-valve.html#comments Mon, 03 Mar 2008 04:34:44 +0000 http://checkthishouse.com/testhouse/?p=17 TPR ValveWater Heater TPR Valve Water heater TPR valve must be installed on every water heater (gas or electric). TPRV – Temporary Pressure Relief  Valve Water heater TPR valve is also known as Watts Temperature and Pressure Relief Valve. The pressure relief valve is usually located on top or side wall of the tank enclosure (tankless water heater safety valve, also known as T&P valve is located underneath the appliance). Some old water heater tanks (1960s or earlier – they are still operating in some houses), were not equipped with pressure relief valves, and I would highly recommend replacement for safety and financial reasons [...]]]> TPR Valve

Water heater TPR valves must be installed on every water heater (gas or electric).

TPRV – Temporary Pressure Relief  Valve. Water heater TPR valve is also known as Watts Temperature and Pressure Relief Valve. The pressure relief valve is usually located on top or side wall of the tank enclosure (tankless water heater safety valve, also known as T&P valve is located underneath the appliance).

Some old water heater tanks (1960s or earlier – they are still operating in some houses), were not equipped with pressure relief valves, and I would highly recommend replacement for safety and financial reasons (sediment at the base of old tanks is so thick, that it takes much more gas to heat up the same amount of water).

Every water heater requires TPR valveWater heater TPR valve releases excessive tank pressure if for any reason it reaches an unsafe level, that’s why all tank type units MUST HAVE a pressure relief valve installed, otherwise they could simply blow up. Because some of us are very creative, and you might own a property purchased from such a person,  below are the major no-no’s.

If something listed below appears to be similar to the installation in your home – FIX it immediately!

Every water heater TPRV requires discharge pipeTankless water heater T&P safety valve also requires discharge pipeWater heater TPR valve must have a discharge pipe attached to it (blue tubing on this picture is just one of the few permitted types of pipes).  Discharge pipe should extend from the water heater TPR valve and terminate within 6″ from the floor surface (distance and discharge location might slightly vary between some jurisdictions, so check with your local code enforcement division, or local / licensed plumber).

Such installation is required so if the valve needs to relief pressure / hot water, it will be discharged at the floor level, and not sprayed at your face or / and body.

Newer discharge water heater TPR valve into the sink, tub, shower, etcWater heater TPR valve discharging into the sink, tub, shower, etc creating a safety hazardWater heater TPR valve discharging into the sink, improper pipe materials used - safety hazardWater heater TPR valve should never discharge into the sink, tub, shower stall, etc. Emergency discharge of hot water / steam might cause severe injury. Keep the discharge pipe low, always pointing down and within 6″ from the floor level – you may also pipe it directly into the floor drain.

Water heater TPR safety valve discharge pipe must be always pointing downWater heater TPR safety valve discharge pipe should never be downsizedWater heater TPRV discharge pipe should never be downsizedWater heater TPR valve discharge pipe must be the same size as the valve’s discharge end, which is 3/4″ in diameter. The reason is simple – it has to be able to relief the same amount of water as the amount coming through the inlet side of the water heater, no reductions should be made or any type of valves installed between the safety relief valve valve and discharge pipe end.

No threads are permitted at the discharge end of TPR valve pipeThere should be no threads at the end of the water heater TPR valve discharge pipe, because when this valve starts leaking / dripping, and there’s a thread at the end of pipe… some of the home owners cap it, which creates a very dangerous situation. Whenever the safety valve will be required to open because of the increasing temperature / pressure,  that capped discharge pipe might cause the water heater to blow up.

PVC pipe can not be used for the water heater TPR valve dischargeWater heater TPR valve discharge pipe must be made out of same materials that is used for water distribution – galvanized steel, hard-drawn copper or CPVC (regular PVC tubing would not withstand high temperature and it is not permitted). If you are planning to use anything else, make sure that it is approved in your jurisdiction.


The discharge pipe from the relief valve on the water heater has been incorrectly plumbed uphillDischarge pipe from the water heater TPR valve must always run downhill- if the TPR valve opens occasionally, and water / steam instead of being drained, accumulates / floods the valve, it might eventually cause its corrosion, and prevent it from functioning properly or at all.

Water heater TPR valves should be tested periodically (as recommended by the manufacturer). There is a small lever on the top of the valve, which opens the valve when lifted.

BUT – most of the home owners never do it, and any type of valve tested for the first time after long period of time might not close anymore and will keep leaking. So before you make any testing attempts, first follow this short check list:

  1. Make sure that you know location of the cold water shutoff valve (main or dedicated for water heater), and that it is functional … just in case you have to use it
  2. Make sure that there’s a properly installed water heater TPR valve discharge pipe
  3. Make sure that discharging water will not damage your flooring material (you can place a bucket underneath and even cover the top with a towel to prevent hot water from over-spraying surrounding area)
  4. If it’s an old water heater, I wouldn’t even test the TPR valve, but it would make sense to replace – they  are very cheap

Don’t forget your tank gas water heater maintenance, it’s a very important task!

Now, go ahead and check your water heater TPR valve installation…

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