Potential Reasons Your Air Conditioning Thermostat Controls Aren't Working

Posted on: 30 November 2015

Central air conditioning systems are multifaceted appliances that require all of the parts to work in order to provide your home with the most efficient cooling. When problems seem to occur with your temperature controls like the thermostat or remote, your unit can either not turn on at all or won't provide the proper level of cooling.

There are a few potential reasons your temperature controls don't seem to be working – and the problem isn't always the temperature controller itself.

Thermostat Remote Isn't Working

Do you use a remote controller to trigger the thermostat controls inside your home? Has the remote stopped working? The first place to check is obviously the battery compartment on both the remote and the thermostat. If you haven't changed the batteries in your thermostat in a year, now is the time to do so even if the batteries don't seem low.

The next step is to check if the thermostat itself is working after the battery replacement. If nothing happens when you manually use the thermostat, you might have a problem elsewhere in your HVAC system and that problem might require the assistance of an air conditioner technician.

Thermostat Won't Turn on the AC

Does the air conditioner completely fail to turn on no matter how far you lower the thermostat temperature? There could be a problem with the compressor, which is located in the condenser unit outside your home.

Lower the temperature on the thermostat then head outside to the condensing unit to check for sounds. If the unit sounds like it is powering up normally, then you might simply need a new thermostat. If the unit sounds eerily quiet, the air conditioner might have suffered a compressor failure.

The compressor starts the cooling process by pumping out gas refrigerant that serves as the system's fuel. If the compressor doesn't pump out that refrigerant, the rest of the system has nothing to do.

Replacing or repairing a compressor is not for a novice. Call in an HVAC technician for assistance.

AC Output Doesn't Match Thermostat

Does your unit turn on but the inside of your home fails to cool to your desired and thermostat-defined temperature? The problem could again be the sensor in your thermostat or a compressor that is starting to fail. But you could also have dirty or broken condenser coils and that's something you can check on your own.

Turn off all power to your air conditioner using the fuses next to the condensing unit. Remove the lid to the unit's casing and peek inside. You should see some coils twisting around on one wall. Those are the condenser coils, which convert the compressor's gas refrigerant into liquid and then sends that liquid inside for cooling.

Visually inspect the coils for signs of debris like leaves or twigs and any dirt buildups. You can clean off dirt using a gentle hand and a steel brush. If you have a really careful hand, you can rinse the coils from the inside using a hose but make sure water doesn't pool in the bottom of the condensing unit.

If you see damage to the condenser coils, call in an air conditioning technician immediately as you might also have a refrigerant leak. If the coils look fine and your system still isn't working right, ask an HVAC tech to check your compressor and thermostat sensors.