A dead thermostat battery is the most common cause of a thermostat not working properly. However, what happens when you’ve changed batteries in the thermostat and then the AC stops working? 


Thermostat Not Working? 8 Common Thermostat Battery Problems

Many homeowners have experienced a problem with the AC not working after replacing the thermostat battery at least once. This can be due to a variety of reasons that range from minor problems with a simple fix to larger, mechanical or electrical issues. So here are the top eight causes of an unresponsive thermostat, even after changing the batteries. 


The Thermostat Needs a Reset

After changing out the batteries, it’s good practice to perform a manual reset for your thermostat to help restore the connection. As each brand and thermostat model will be slightly different, the easiest way to reset a thermostat is to follow the thermostat’s manual.

Using Wrong Size/Type Batteries

Once again, be sure to consult your thermostat manual as it will have the correct size and type of battery listed. Some thermostats also have the battery voltage required on the inside of the battery compartment. Always make sure to replace both batteries at the same time, don’t mix used and new batteries.

Improper Thermostat Battery Placement

Besides using the wrong batteries, installing the batteries backwards or without snapping them all the way into place is the most common issue. Take a moment to inspect the batteries and ensure the negative and positive ends match the depiction on the battery compartment.

Insecure Thermostat Cover Connection

When replacing the thermostat cover, ensure the cover has snapped back into place properly. Without a secure connection, the thermostat won’t be able to communicate with the HVAC system.

Blowing Hot Air

What if the thermostat is working but heat is coming out of the vents instead? Do a quick check to see if the thermostat settings were accidentally switched while changing the batteries.

Breaker Tripped

If you noticed your breaker switch for the AC was off when you went to reset the thermostat, a tripped breaker might be the issue. After flipping the breaker switch, give it a few minutes and check the thermostat. Keep in mind, the tripped breaker might be a sign of other issues. An HVAC inspection can help diagnose the source of the electrical surge.

Clogged Drain Pan

A safety feature within the HVAC system is the float switch. This switch monitors the water levels of the drainage pan and shuts down the AC when tripped. Until the clogged drainage pan or line is drained, the AC won’t turn back on, regardless if the thermostat has new batteries.

An Old Thermostat

Similar to other components in the HVAC system, a thermostat can stop functioning simply due to old age. Typical thermostats will last around 10 years before needing a replacement. Other signs of old age include: constantly shutting down, incorrect temperatures, strange noises. 

Satterlee’s Thermostat Replacement Services 

While it might not be malfunctioning from age, if your thermostat is over 10 years old then it’s time to start shopping for a upgrade. In addition, this is one of the best times to look into the different benefits of programmable thermostats. Regardless of the HVAC advice or service you need, you can count on our skilled HVAC technicians. Contact Satterlee to schedule a service today, so you can have confidence in your HVAC investments.


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