How To Fix It

How to Reset Lennox Furnace?

You can reset a Lennox unit just like any other furnace.

To reboot a unit that has a reset button, you would have to locate it (the button is under the control access panel, next to the ignition control box), push and hold it for 10 seconds, and then release the button. You can also reset the furnace at the breaker.

How to Reset Lennox Furnace?

The majority of Lennox furnaces have a reset button, so all you would have to do is simply find it and push it to restart the unit.

  1. Turn off the electrical supply to the furnace.
  2. Find and remove the control access panel. On downflow furnaces, you’ll find the panel at the bottom, while upflow models will have the panel at the top of the unit.
  3. Next to the ignition control box, you should be able to locate a raised switch or button.
  4. Press and hold the limit control switch (that’s how the reset button is called) for about 10 seconds, and then release it.

Where Is the Reset Button on the Lennox Furnace?

In a lot of cases, you would have to expose the furnace’s control panel and then search for a raised button (it is typically red).

How Do You Manually Reset a Furnace?

You can manually reset your Lennox furnace by pushing the reset button. If for some reason, that is not possible, you can always manually reboot the unit by turning it on and off at the circuit breaker.

Flip the breaker responsible for the furnace off, wait for around 10 minutes, and then turn it back on. Give the system a few minutes to return back to normal operation (don’t forget to turn the thermostat on). 

Read: Lennox Furnace Not Staying On

How Do You Reset a Lennox?

To reset a Lennox unit, all you would have to do is press the reset button. However, before doing that, you would have to make sure that the furnace is turned off (ideally, you would want to turn it off at the circuit breaker as well).

Leave the furnace turned off for a few minutes before removing the control access panel as the components might still be hot.

Read: Why Lennox Furnace Not Igniting

Where Is the On/Off Switch on My Furnace?

Some furnaces have a disconnect switch that typically looks like an ordinary wall switch. 

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Building codes require any furnace to be supplied by its own dedicated circuit; this circuit wiring runs from the service panel and to the disconnect switch that can be located either on the wall next to the furnace or on the side of the actual unit

Troubleshooting Lennox Furnace Reset Button

A reset button on any furnace is a safety feature. It will shut the unit down, if the furnace becomes overheated – this will prevent the unit from triggering the circuit breaker.

You might find the reset button tripping over and over again if:

  • The unit is overheating (this usually happens if there’s not enough airflow)
  • There is no gas
  • The air filter is clogged 
  • The gas valve is malfunctioning
  • There is an issue with the flame sensor

Why Does Furnace Need To Be Reset?

The main purpose of a reset button is to shut the Lennox furnace down before it trips the circuit breaker. This can happen if the unit is overheating.

The reset button can also be used to turn the furnace back on after a power outage, for example.

What Happens When You Press the Reset Button?

The reset button is connected to sensors that monitor the flame in the burner and the temperature inside the unit. If the flame goes out or the unit starts to overheat, the button will get triggered and this, in its turn, will shut the whole unit down

This is done to prevent any further damage that might occur if the system continues running. 

Read: Lennox Furnace Problems You Need To Know

Why Is My Lennox Furnace Not Heating?

There are a few reasons why your Lennox furnace might not be heating up:

  • A faulty or cracked igniter
  • A defective or dirty flame sensor
  • A malfunctioning or tripped flame rollout switch
  • A dirty filter
  • Closed heat registers
  • A malfunctioning thermostat
  • Issues with the control board or draft inducer motor

What Would Cause a Furnace Not to Kick On?

  1. Wrong thermostat settings are one of the top reasons for a furnace not turning on.
  2. Issues with the gas line can also be to blame.
  3. The furnace on/off switch may be off or the unit might be turned off at the circuit breaker.
  4. A clogged air filter can be tripping one of the switches (this will make the unit shut down).
  5. There is an issue with the pilot light or the ignition sensor

Why Is My Lennox Furnace Blowing Cold Air?

If you have already given your furnace a few minutes to warm up and if you are sure that the thermostat settings are correct, then the pilot light might be out.

Dirty flame sensors and insufficient gas supply can also be making your furnace blow cold air. 

Read: Why Lennox Furnace Is Not Staying ON

What Does Blinking Light on Lennox Furnace Mean?

Blinking LED lights are your furnace’s way of telling you that something is wrong. Some of these error codes might indicate:

  • Combustion failure
  • Malfunctioning of the pressure switches
  • Furnace lockout
  • Issues with the high limit switch, and so on

Your Lennox furnace might also start to blink right after you have reset the unit. That is completely normal and the light will stop flashing as soon as the system finishes checking itself.

How Do I Clear Lennox Error?

Sometimes, resetting the furnace might help you clear out the error code. A system reboot will delete the unit’s onboard memory, and if there is nothing wrong with the furnace, the error code will not appear again. 

Read: Lennox Furnace Problems

How Do I Reset My Furnace Lockout?

A lot of furnaces will exit lockout mode on their own in a few hours. If that doesn’t happen, then you would have to manually turn the power to the furnace off and then back on again

Does a Lennox Furnace Have a Pilot Light?

Newer gas furnaces have spark ignition, but if you have an old Lennox furnace, then you might still have a standing pilot light. In such a case, you might have to not only reset the actual furnace but also manually relight the pilot.

Where Is the Pilot Located on a Lennox Furnace?

A pilot light is located within the combustion chamber. You’ll locate it if you follow the tube from the gas valve.

How Do You Light the Pilot on a Lennox Furnace?

Before attempting to light the pilot on your furnace, make sure that you have turned the switch or the knob at the bottom of the unit to the ‘off’ position. Wait for at least 5 minutes before proceeding – this will allow the remaining gas to dissipate.

Why Is My Lennox Thermostat Not Working?

Your thermostat might not be working if its batteries have drained or if it is turned off at the circuit breaker.

Why Does My Lennox Thermostat Keep Resetting?

If your Lennox thermostat is constantly resetting, then it might be because:

  • There is a blown fuse
  • You have faulty wiring
  • The HVAC system is short-cycling
  • The actual thermostat is malfunctioning