The Purpose Of Pressure Limit Switches In Your AC And When They Signal The Need For AC Repairs

Your AC has a few built-in safety mechanisms that protect it from damage. The safety features shut down the AC so it won't operate and damage parts when there is a malfunction. Two of these safety devices are the pressure limit switches. Your AC probably has a high-pressure limit switch and a low limit switch. Here's how they work and how they signal the need for AC repairs.

The Purpose Of AC Pressure Limit Switches

The pressure limit switches monitor the refrigeration cycle in your air conditioner. If the pressure gets too high, the high limit switch is triggered and the AC shuts down so the compressor and other parts of the AC aren't damaged. If the pressure gets too low, the AC shuts down so the coils don't freeze over and become damaged.

Some Things That Trigger A Pressure Switch

The low-pressure switch can be triggered by a loss of refrigerant through a leak. This switch may not have a manual reset button. If it's triggered, you'll probably need to call an air conditioning repair service to find the leak and repair it before your AC will operate properly again.

The high limit switch usually has a reset button. The cause of it triggering might be something temporary that you can fix, such as a dirty condenser coil you could clean and then reset the switch. However, if the switch trips again, you'll want a repair technician to troubleshoot the problem so repairs can be made.

The Repairs Your Air Conditioner Could Need

If a high-pressure limit switch keeps tripping, it could be a sign the switch is bad or it could indicate there is a problem with another part, and the switch is tripping to protect the AC. Problems with the fan or fan motor in the condenser can cause the switch to trip. The repair technician might have to replace the capacitor in the fan motor or replace the motor itself. It may be necessary to adjust the fan blades or clean them if they are so dirty they have difficulty turning freely.

The AC repair technician may also check the settings on the switch to make sure the setting isn't too high or too low. In addition, the switch can be tested to make sure it's functioning properly.

If the switch is bad, it has to be replaced and adjusted to the proper settings. Your HVAC can then be monitored to make sure it's working properly and that there are no other problems causing the switch to trigger. Contact an HVAC contractor to learn more about air conditioning repair.