The Thermostat is an important component of your Lennox air conditioning system. If something goes wrong with the air conditioner's thermostat or if it is installed incorrectly, it may have a huge impact on how comfortable you are with your unit. However, an HVAC technician is not required for every Lennox air conditioner thermostat problem. So, we would like to provide some Lennox air conditioner thermostat troubleshooting tips so that you can try to fix the issue.

Lennox Air Conditioner Thermostat Troubleshooting

Before performing your Lennox air conditioner thermostat problems troubleshooting, first, you should check four things regarding the thermostat.

Is your AC thermostat receiving power?

If your thermostat is turning on and off always and if its backlight is not working properly, you must check whether it is receiving adequate power or not. This is the first thing you must do regarding your thermostat. Generally, the thermostat in your air conditioner will get power from batteries as well as the cooling system. So, you have to ensure that the power coming from both of these sources.

See if the circuit has tripped and is caused the unit to lose power. Once, you have confirmed that everything is fine with the circuit breaker and fuses, you need to go through the batteries replacement. Yes, you must be done the replacement of batteries in your thermostat.

Is your thermostat mounted properly on your wall?

To get the correct reading of your home's temperature, the thermostat should be installed and mounted properly on your wall. When your thermostat shows fault reading, you can check it. By using a bubble level, you can check whether the thermostat is fixed as straight on the wall or not. If it is not placed correctly, you have to adjust it accordingly. Moreover, remember that your thermostat is mounted at least five feet from the floor.

Is your thermostat near hot or cool air sources?

If you are not getting the correct temperature reading of your home on the thermostat, it may has near hot or cool air sources. So, make sure to keep the thermostat away from these types of sources such as windows, vents, direct sunlight, appliances, etc. that can influence the surrounding temperature.

Is your thermostat dirty?

Dirt and dust buildup is a problem for any component of your Lennox air conditioner including the thermostat. So, you need to clean the unit regularly. If the thermostat is malfunctioning, you need to open the cover and clean gently any dirt that has buildup on the inside of the thermostat.

It’s better to first check the above four basic things when you feel that your thermostat in the air conditioner has problems.

Lennox air conditioner suddenly stops running

A malfunctioning thermostat causes sudden changes in your cooling system. So, you should fix it immediately.

Check if there is lighting on the thermostat display. If not, it can't signal the AC to cycle on. In this condition, you need to find the reasons related to why your thermostat is not getting power such as due to dead batteries, tripped circuit breaker, or blown fuse.

Check for buildup of dust, dirt, smoke, etc. A coating on the components can affect the thermostat's normal operation so you have to clean them carefully with a soft brush or canned compressed air.

Inspect the problems with other components such as loose wiring and terminal screws that need to tighten.

Room temperature does not reach the thermostat setting

If there is buildup of grime, it can cause inconsistency between the actual room temperature and temperature setting on the thermostat. However, it may be a good choice that cleaning the unit before taking any further steps.

Improper installation also caused variations in the temperature readings. So, you have to correct it by adjusting the sitting place.

Check if the heat anticipator is stuck if your thermostat is a mechanical model. You can locate this anticipator on a circular dial in the form of a little metal arm. Push the arm carefully in either direction to become free.

Make sure the thermostat is located away from the direct sunlight and other heat & cold drafts.

Continuous Running or Short Cycling

If you get these types of Lennox air conditioner problems, first you should check for two issues with the thermostat. Verify whether it is placed level and dirty inside. As both of these issues can trigger short cycling and cause continuous operation, you have to resolve these by following the instructions given in the manual.

Another possible cause is a poorly calibrated anticipator. Extend the cooling cycle period by adjusting the anticipator arm in single notch increments toward the marking for "longer" on the round dial. Wait until the completion of a full cycle on the air conditioner in between adjustments and see the result.

Final Thoughts

That's all about a few Lennox air conditioner thermostat problems and their troubleshooting tips. If you are unable to resolve the problem with the above tips, you can contact an HVAC professional to determine the cause and solution. If your thermostat is broken, you need to replace it to get the best result.