How To Test A Home Thermostat

Are you having problems with your home thermostat? Maybe it’s not heating or cooling your house correctly, or it’s just not working at all. In either case, you need to test it to find out what the problem is.

In this guide, we will walk you through the process of testing a home thermostat so that you can identify the issue and get it fixed quickly! Remember, a thermostat is like your HVAC’s brain — if it has a problem, you can bet that your entire system might not work as desired.

But before testing the thermostat, it’s crucial to understand what you are looking for. For instance, if your thermostat is not working, there are several issues that might be causing this. 

So, let’s start here:

Main Issues with a Home Thermostat

Several things might be wrong with your home thermostat. 

For example:

  • A faulty thermometer
  • Disconnected or loose wiring
  • The thermostat is not powered
  • Wrong settings on the thermostat
  • Batteries need replacement

With this in mind, it will be easier to test your thermostat and spot signs of each of the probable issues. 

Crucial Tips on How to Test a Home Thermostat

So, if you don’t know how to test a thermostat, here are the major steps to follow (the steps will depend on what problem you are testing for):

  1. Testing for a Dead Thermostat

It is a problem if your thermostat is not powered. So, the first thing you need to do is test the thermostat power. In most cases, a home thermostat uses AA or AAA batteries.

Therefore, open the battery compartment and check if they need replacement. If they do, replace them with new ones and re-test your thermostat.

  1. Testing for a Faulty Thermometer

This is another typical issue with home thermostat systems. Its thermometer might be faulty, thus offering wrong temperature readings. To test this, pick a well-calibrated home thermometer to do the test.

First, take the home thermometer and tape it on the wall near your thermostat.  Use a thick paper towel to separate the wall and the home thermometer. This will ensure that it doesn’t read the wall’s temperature but rather the ambient room temperature.

Leave the thermometer on the wall for approximately 15 minutes before checking the readings.  Now compare the two temperature readings. If they differ by more than a couple of degrees, then your thermostat’s thermometer is most likely faulty.

If you get similar readings from both devices, then there might be another problem with your thermostat.

  1. Testing for Disconnected or Loose Wiring

This is a more serious problem due to the fact that it can potentially lead to a house fire. While testing for disconnected or loose wiring, the first step is to go to the circuit breaker and turn off the system.

From here, you can open the top panel of your thermostat and check the wiring.  Ensure that all the wires are tight in their terminal screws and not loose. If you see any loose wire, screw it in tightly.

Now turn on the power to your thermostat at the circuit breaker and test it to see if it’s working.

  1. Loose Heat Anticipator

The heat anticipator is a small resistive device located in your thermostat. It’s used to turn the furnace off before the room reaches the desired temperature.

If this part is not working correctly, it will cause your furnace to run longer than necessary. As a result, you’ll end up with an overheated room or wasted energy.

To test the heat anticipator, first, locate it in your thermostat. It’s usually a small knob that you can turn with your fingers.

Turn it clockwise until it reaches the end of its shift. Now set your thermostat to a lower temperature and wait for the furnace to turn on. 

When it does, observe the furnace’s cycles. If it turns off and on frequently, then the heat anticipator is most likely not working correctly.

  1. Wrong Setting on the Thermostat

This is a problem that you can easily fix by yourself. Just follow these steps:

First, turn off the power to your thermostat at the circuit breaker.

Then, open the top panel of your thermostat and locate the dip switches. These are used to set the time, day, and temperature.

Check the settings and ensure that they are correct. If not, change them accordingly and re-test your thermostat.

  1. Thermostat Sending Wrong Signal

Sometimes, the problem might not be with the thermostat itself but rather with the signal it’s sending to the furnace. Therefore, the last step of how to test a home thermostat is testing for the signal.

And to test this, you’ll need a multimeter. First, set your multimeter to measure AC voltage and turn off the power to your thermostat at the circuit breaker.

Open the top panel of your thermostat and locate the two wires that go to the furnace.

Now, touch one probe of your multimeter to each wire in turn and check the readings. If you don’t get a voltage reading, then the problem is most likely with your thermostat.

But if you do get a voltage reading, then the problem is most likely with your furnace.

This test can also be done manually. For example, after you take your thermostat’s top panel off, untwist those R and W wires from their connectors. Then, twist them together and turn the furnace breaker back on.

If doing this turns the furnace on, it means that the furnace isn’t getting a signal from the thermostat. But if it doesn’t turn on, the problem might as well be with the furnace.

How to Fix your Thermostat Issues

After testing thermostat issues, how do you fix them? Well, some problems are easy to fix by yourself. 

For example, if you find that the batteries need replacement or the settings are incorrect, you can easily do those by yourself.

But for more serious problems like a loose wire or a dead thermostat, it’s best to call a professional — even if you are well-versed in HVAC repairs.

Professional HVAC experts have the necessary experience and expertise to quickly identify, repair and test thermostat issues without causing any further damage. They can even install a new thermostat if your thermostat is due for a replacement.

So, if you’re having trouble with your home thermostat, don’t hesitate to call a professional. It’s the best way to ensure that the problem is fixed correctly and quickly, and safely.

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