How to Reset a Lennox Thermostat [All Models]

If your Lennox thermostat is malfunctioning, resetting it can help resolve the problem. More so, you want to reset your thermostat to change temperature settings or reprogram it completely.

In this guide, I’ll show how to reset your Lennox thermostat in seconds—a method that works for all Lennox thermostat models (Lennox ComfortSense and iComfort models). Let’s get started.

To reset your Lennox Thermostat, follow these steps:

Locate the circuit breaker panel in your home. This is the main power distribution panel in your home.
Look for your HVAC circuit breaker—usually labeled “HVAC” or “Air Conditioner.” Make sure it’s the breaker that controls your Lennox thermostat.
Now, turn the breaker off. Then wait 30 seconds and turn it back on.
Your Lennox thermostat is reset. Return to the thermostat and turn it on—if it’s not already turned on.

If you’re using a battery-powered Lennox thermostat, you can also reset it by doing the following:

Turn off the thermostat.
Remove the battery cover. If the battery cover is at the back, you’ll need to remove the thermostat from the wall to access the cover.
Remove the batteries. Next, reinsert the batteries backward. That is, place the negative ends of the batteries in the positive part of the thermostat’s battery terminals.
Wait 5 seconds, then remove the batteries and reinsert them properly.
The thermostat display will turn on and the reset should have been complete.

If you’ve reset your Lennox thermostat to fix some malfunctions but the problem persists, keep reading to see other fixes to try.

Troubleshooting a Lennox Thermostat

So here are other fixes to try if your Lennox Thermostat doesn’t work after resetting it:

Replace the Batteries

If your Lennox thermostat is battery-powered, low battery power might be the reason the device isn’t working properly.

Get a new pair of alkaline batteries and replace the old ones. When inserting the batteries, check if the battery terminals are corroded. If so, use a soft cloth to clean the terminals to allow current to pass through them properly.

More so, ensure you insert the battery properly.

Remove Dust/Debris

Your Lennox thermostat may develop some faults because the inside of the device is dusty. Dust/debris can prevent the wires from getting current from the terminals, hence the thermostat may stop working.

Remove your thermostat cover (if needed, remove it from the wall) and clean the inside properly. You can use a vacuum hose to remove dust and debris from the thermostat.

You can also use a soft brush/cloth to clean your thermostat.

Check the Wiring

Pinched or burned wires could be the reason your thermostat is malfunctioning. If you’ve tried other fixes and the problem persists, check your thermostat wires.

If you have burned wires, you’ll need to replace them to get your Lennox thermostat to work again.

If you’re not sure how to handle wiring issues in your thermostat, get an expert to help you.

Closing Thoughts

Some Lennox thermostat models may come with a reset button that users can press down for a few seconds to reset the thermostat.

If your Lennox thermostat doesn’t have this feature, you can reset it by flipping the circuit breaker on and off or removing the batteries and reinserting them backward.

And if you don’t achieve the aim of resetting your thermostat (perhaps it’s faulty), you can try other troubleshooting tips highlighted in this post.