7 Signs that Your HVAC Control Board Needs Troubleshooting


An HVAC system is an integral part of every modern home. It keeps you cool during hot summer days and warm during the winter. However, since your HVAC system is almost constantly running, it tends to develop occasional problems.

It consists of many parts, and all of them need regular maintenance to stay functional for a longer time.

Even with that, it is still challenging to keep everything in check. Still, if some parts break, there are ways for you to fix them without calling professionals.

This article will discuss the control board, what it is, and the most common issues. Make sure to read until the end to find out more.

What Is The Control Board?

The control board is a crucial part of your HVAC system. As the name suggests, its purpose is to control the system, the temperature, activate the blower, and several other operations that help the entire system to run efficiently.

A control board is where you find the thermostat wires connected to the heating and cooling system.

Generally, you can locate the board on the furnace or the air handler. Unfortunately, like many other parts of your HVAC, the control board also tends to malfunction

7 Reasons for Troubleshooting Your HVAC Control Board

The control board does not break down that often, and it is certainly not the first element you should look into. However, there are a couple of occasions where you might want to pay some attention to it.

1. Blinking Lights

Most HVAC systems have access panels where you can find a plastic or glass port with LED lights. If you see these lights blinking, there might be a reason for concern.

They usually blink in patterns, so there may be an issue if you notice anything odd with it. For example, they might blink four times in a row or three times with short breaks.

To diagnose the problem correctly, refer to your user’s manual, where you will find error codes. The error codes will show you if there is something wrong.

For example, some codes can show you low voltage, which would mean that there is a problem with the control board. You should call in technicians to help you deal with this problem.

2. Inconsistent Temperature

If you notice that the temperature in your home fluctuates constantly, or if it suddenly gets too hot or cold, this might be a sign that the control board is acting up.

Sometimes, the board does not give proper directions to other parts of the system, which can cause a whole mess. For example, it can turn off certain parts sooner than it should or keep them running longer than necessary.

Of course, you should first check the thermostat for malfunctions. If it does not show any signs of problems, make sure to call professionals to check out your control board.

3. Interruption of the Regular Sequence of Events

Generally, the HVAC system is designed to follow a particular sequence. Once you turn it on, some parts start working before others, and so on. For example, the induced draft motor starts first, it is then followed by the pressure switch closing, and so on. 

If you notice any irregularities in the sequence of events that your HVAC system is used to, it might be a sign that there is an issue.

There are quite a few signs that the control board is messing with the routine. For example, the blower might not turn off, the ignition does not want to turn on, or the gas jets will not activate.

All of these problems indicate control board malfunctions. Call your service provider to check out the problem before it gets unbearable!

4. Bad Solder Connections

It is of utmost importance to have a proper solder connection as this is one of the most common issues when it comes to the control boards. Basically, plugs with stems are soldered to the metal circuit. If done poorly, this might cause a lot of concerns.

They do not necessarily have to be broken. There can also be cracks and fractures that create gaps between the stems causing the circuit to stop working.

5. Thermal Expansion

The thermal expansion goes back to bad solder connections because this is what causes them in the first place. The joints must be adequately formed to suit the metal circuit; their shape should be slightly concave. 

Once that is done, they begin to get warm, which creates expansion. The expansion changes the form or creates gaps, which then leads to control board problems.

These problems might not be evident immediately, as it might take time for you to notice this issue. Luckily, it is not difficult to fix this, but you should not do it on your own.

6. Switches Get Stuck

Electromechanical switches are crucial to the control board. Much like other devices, if you do not use something very often, it slows down or gets stuck. The switches on control boards tend to stop moving after a certain time.

However, they usually get stuck due to under or over-voltage. If there is a significant voltage spike, it can cause overheating. Overheating wears down the switches, causing them to stop working. On the other hand, too little voltage can prevent the relay’s contacts from staying closed.

However, these are not the only issues that might wear down the control board switches. This can also happen due to, for example, electrical currents.

7. Transistors

Transistors are one of the first components on the control board that start working.

Unfortunately, as they are a part of the start-up process, too much heat and energy created can damage numerous components. This can completely ruin your control board or cause it to work much slower.

Final Word

Quite a few problems can cause your control board to start acting up or stop working altogether. However, there are usually ways to fix these problems.

You can fix some of them with some simple troubleshooting, but others require an expert’s attention. Make sure to take good care of your HVAC system components!

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