Tank Gas Water Heater Maintenance 2: TPRV, Tank Drainage, Flue-Way

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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