Lennox Heat Pump Not Working – What To Do?

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Did your Lennox heat pump suddenly stop working or won't turn on after a power failure? Is it not warming or cooling your home as efficiently as it used to? Don't call the technician just yet! We researched Lennox troubleshooting tips for you and what you can do to avoid costly service.

If your heat pump won't start or suddenly stops working, here are the possible reasons and what you can do:

  1. The heat pump has no power: Make sure all switches are turned on and reset the circuit breaker.
  2. Components are frozen: Clean the filers to improve airflow and melt the ice at the outdoor unit carefully using a water hose.
  3. Faulty thermostat: Recalibrate thermostat settings and replace the batteries with new ones.
  4. Damaged components - If you suspect damaged components, have them checked by a technician and replace parts as advised.

Read on as we guide you through some basic heat pump troubleshooting. You'll also learn tips on improving the efficiency of your Lennox heating system and how to contact their customer service.

air conditioner in the new house system outdoor unit, Lennox Heat Pump Not Working - What To Do?

Why Is My Lennox Heat Pump Not Working?

Lennox heat pumps are one of the most durable and energy-saving brands for heating systems. It provides comfort to your family year-round without the burden of high energy costs. That's why it can be frustrating when it suddenly stops working.

There are many possible reasons why your heat pump isn't working. It could be an electrical problem, a broken component, or an incorrect setting. Below are the possible reasons why your heat pump stops working and what you can do about it. 

1. Heat pump has no power

If your heat pump is not getting power, you won't hear any of the components running when you turn the power switch on. The first thing you need to determine if you encounter this problem is to check if there's a problem with the power source.

What to do

  • Turn on all power switches: If your unit has a separate indoor and outdoor power switch, check to ensure both are on.
  • Inspect the electrical panel: Go to the primary power source and check if you have blown a fuse or a tripped circuit breaker. You can do a simple circuit breaker reset by unplugging all connected equipment and turning the breaker switch off and on again. If there is a faint burning smell, turn the breaker off and call a technician immediately.

If the power source seems fine and the heat pump still won't turn on, there could be a problem with the thermostat or one of the components. Continue reading to see the things you need to check.

2. Components are frozen

Frozen air conditioning unit covered in snow

During the cold winter season, heat pumps are prone to freezing, especially if there are obstructions in the airflow and the unit can't defrost properly. If your heat pump suddenly stops warming your home and you suspect that it's freezing up, here's what you can do:

What to do

  • Turn on the fan: If you see frost on the outdoor unit and the heat pump is not defrosting, switch off the heat setting and change the thermostat to fan mode. Wait for a few minutes for the ice to melt before returning to your desired thermostat setting.
  • Melt the ice in the outdoor unit: Using a water hose, melt any ice that forms in the casing of the outdoor unit. If the ice is too thick, you can use warm water to thin the ice before watering it down. Do not try to break the ice using a sharp object to avoid damaging the components.
  • Clean dirty filters: Maintaining clean filters will ensure proper airflow and prevents the unit from overheating. Adequate airflow will help the heat pump defrost efficiently, prevent evaporator coils from freezing and ensure appropriate air transfer.

If there's too much ice forming in your heat pump and the defrost mode can't handle it, there might be a problem with the defrost function or low refrigerant levels. A technician should be able to diagnose the issue further.

3. Faulty thermostat

Man uses a mobile phone with smart home app in modern living room

If your heat pump is not heating/cooling like it used to, not turning on, or keeps changing settings on its own, there could be a problem with the thermostat. It could be a wrong setting, incorrect installation, faulty wiring, or a damaged thermostat.

What to do

  • Ensure settings are correct: Set the thermostat to 'heat' during the cold season and 'cool' during warmer seasons. Recalibrate the thermostat setting, or if it continues to malfunction, it might be time to replace the unit.
  • Replace the batteries: If the thermostat has no display, it's likely due to drained batteries. Remove the unit from the wall and open the battery compartment behind it. Lennox thermostats typically use AAA batteries. Replacing it should solve the problem.

Lennox products use their own line of iComfort Smart Thermostats compatible with their heat pumps. If you need a thermostat replacement, you can contact iComfort Support.

You can also read more about heat pump thermostats in this article: Do I Need A Special Thermostat For A Heat Pump?

4. Damaged components

HVAC technician servicing home heating and cooling system.

Through the years, as the heat pump ages, just like any other equipment, several of its components may start to show signs of wear by malfunctioning or breaking down. According to reviews, one of the first things that might break down is the thermostat.

When your heat pump suddenly fails to switch between cooling and heating modes, it could be a sign of a damaged reversing valve.

It is difficult to tell which parts of a heat pump will most likely break down, but when it's something as significant as the compressor, then there are several things to consider because of the high cost of replacement.

What to do

  • Replace the thermostat: Signs of a damaged thermostat are failure to turn on even after changing the batteries and frequent malfunctioning settings. Contact your nearest dealer for a replacement. 
  • Replace the reversing valve: If the problem is difficulty changing from heat to cool mode, it could be a damaged reversing valve. It's still practical to order a replacement. The cost would be around several hundred dollars plus the labor fee to replace the valve.
  • Compressor replacement: If you need to replace the compressor, evaluate your heat pump performance and its age. A compressor will cost several thousand dollars, just a little less than the cost of a new heat pump system.

One factor that shortens the life of a heat pump and its components is the lack of maintenance. A neglected heat pump can increase your energy consumption by up to 25%

A Lennox heat pump should be good for 10 to 20 years, depending on how well you take care of it and if you regularly schedule it for maintenance.

What Maintenance Are Required For A Heat Pump?

It is recommended to have your Lennox heat pump serviced by a professional technician once a year to perform the following:

  • Cleaning of ducts, coils, and filters
  • Ensure the thermostat is working properly and in the correct settings
  • Check for leaks and seal as needed
  • Inspect belts, replace if necessary, and lubricate motor
  • Ensure adequate airflow using a special measuring instrument
  • Check refrigerant charge and add as needed
  • Inspect electric terminals
  • Ensure proper heating/cooling performance, and the reversing valve is working properly

How Do You Reset A Lennox Heat Pump?

Resetting a heat pump is an excellent way to resolve any minor problems before you decide to call Lennox technical support. To reset a heat pump, follow these steps:

  1. Turn off the thermostat
  2. Locate the unit's power switch and turn it off
  3. Shut off the electrical breakers
  4. Wait at least five minutes then, turn on the breaker, power switch, and thermostat, in that order
  5. Allow the system to restore for around 15 minutes before making any changes to the settings

Below is a video on how to reset a Lennox heater:

Should I Replace My Old Heat Pump?

alternative energy concept

Suppose the technician finally found the problem with your heat pump, and the solution requires replacing several components. Now, you need to make a big financial decision on whether you will buy the new parts or replace your old heat pump with an entirely new unit. How do you decide?

Lennox provides a simple formula to help you evaluate the situation. Simply determine your heat pump's age in years, and then multiply it with the estimated cost of repairs.

For example:

7 years (unit age) x $1,000 (cost of repair) = $7,000

If the answer exceeds more than $5,000, the best option is to buy a new one because a brand new Lennox heat pump will generally cost less. Generally, if a heat pump is more than ten years old, it's best to consider replacing it.

Lennox sells their replacement parts exclusively, which means you cannot purchase them online or in retail outlets. Contact your local Lennox dealer if you require assistance with parts and services.

Wrapping Up

two heat pumps next to the house

If your Lennox heat pump is not working, always check the power source and the thermostat settings first. If you suspect a component or electrical problem, call Lennox customer service for further diagnosis.

We hope you found useful tips in this article. If you need more information on heat pump troubleshooting and maintenance, we have more great reads below:

How To Pump Down A Heat Pump [A Step-By-Step Guide]

How To Clean A Heat Pump [Inc. Coil And Filter]

When And How To Use The Emergency Heat Setting On Heat Pump

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