Resetting Lennox Air Conditioner: Finding That Button

If you're looking to reset your Lennox air conditioner, finding the reset button is the first step.

However, it's worth noting that many Lennox units do not have a conventional reset button on the control panel.

Instead, resetting a Lennox AC typically involves accessing the high-pressure switch, resetting the circuit breaker, or simply turning the unit off and back on.

To learn more about the reset for your specific Lennox model, keep reading to learn how to get your AC system running smoothly again!

Where is the Reset Button on a Lennox Air Conditioning Unit?

You may have come across information on other sites suggesting that the Lennox reset button is located on the control panel.

However, it's important to note that the Lennox air conditioner doesn't actually have a specific "reset switch."

Instead, it features a pressure switch or circuit breaker that can be reset to restart the system.

For newer models, it usually involves turning the indoor switch off and on or disconnecting the R wire.

Lennox corporation trademark logo and trademark

Below we've specified the location of the reset buttons on Lennox's most well-known and latest AC models.

Model Reset Button Location
Lennox Hs29 Circuit Breaker CB7
Lennox 13acx, EL17XC1, EL16XC1, XC13, 16ACX, ML18XC2, 16ACX, ML14XC1 High-Pressure Switch (Usually with a Red Cap)
Lennox SL28XCV, XC21, EL18XCV, XC20, EL18XCV R Wire or Indoor Unit Button

If your unit isn't listed above, you can find the reset button in the manual by browsing on their product page for more details.

Simply choose "Air Conditioner" in the product category list, select your model's number, and click "Go."

Be sure to read: How To Reset My Air Conditioner [ Reviewing 8 AC Brands]

Why Do I Need to Reset My Lennox Air Conditioner?

There are many reasons why you may need to reset your Lennox air conditioner. A few of these include:

  • Your Lennox air conditioner is making a loud noise and not cooling your home.
  • A breaker kicked into the unit for one reason or another.
  • The unit is leaking water, and the equipment malfunctions.
  • You haven't used the air conditioner in some time and want to activate it again.
  • You turned the device off at the thermostat but would like to turn it back on.
  • Your Lennox air conditioner is not turning on at all for some reason.

How to Reset Lennox Air Conditioner [3 Ways]

If you are experiencing an error code or the unit isn't running properly, resetting the Lennox air conditioner may correct it.

You can do this by either using the high-pressure switch, resetting the circuit breaker, or simply turning the unit off and back on.

Large air conditioning engine located on the roof, How To Reset Lennox Air Conditioner

Below, we've outlined the steps for each.

Resetting the Lennox AC Through the Circuit Breaker (Lennox Hs29)

To reset your Lennox Hs29, simply follow the steps below.

  1. First, turn off the AC unit on the thermostat.
  2. Now, you must locate the circuit breaker that controls the power to the Lennox air conditioner.
  3. Turn that breaker off for at least 30 seconds before turning it back on.
  4. Once the breaker is turned on, you can turn the AC back on using the thermostat.

Resetting the Lennox AC Through the High-Pressure Switch (Lennox 13acx, EL17XC1, EL16XC1, XC13, 16ACX, ML18XC2, 16ACX, ML14XC1)

Some Lennox models have a high-pressure switch that allows for a manual reset.

You can easily restart your unit through these steps.

  1. Switch off the power to the unit by turning off the corresponding breaker.
  2. Carefully remove the back panel of the unit to access its internals.
  3. Locate the high-pressure switch on your unit, which is situated in the liquid line of the compressor.
  4. You'll find a red rubber push or cap switch within this area. Press this switch to reset the pressure switch.

If the issue persists and you observe a yellow light flashing multiple times, it indicates an underlying problem that requires further attention.

Resetting the Lennox AC Through the R Wire or Indoor Unit Button (Lennox SL28XCV, XC21, EL18XCV, XC20, EL18XCV)

For newer Lennox models, a manual reset can often be accomplished using an R wire or an indoor unit button.

Disconnecting the R Wire

To execute a manual reset using the R wire, locate the outdoor control R terminal and gently disconnect the R wire from the outdoor control R terminal.

Power Cycle the Indoor Unit

Another method for manual reset involves power cycling the indoor unit. Simply turn the indoor unit off, wait for a few seconds, and turn the indoor unit back on.

Here's a helpful video for you to understand the process better.

Where is the Lennox Circuit Braker?

So, you've read the steps above, but you don't know exactly where the circuit breaker is.

Here's how you can find and use it:

  1. Find the breaker box. It's often located in the basement, utility room, garage, hallway, or house exterior.
  2. Open the box. The box will have a door on the front. Open it to see the circuit breakers.
  3. Identify the AC breaker. Inside, you'll see a series of switches. These should be labeled - look for one labeled "AC" or "Air Conditioner."
  4. Trial and error. If not labeled, you might need to identify it through trial and error or by observing its control over different parts of the house.
  5. Flip the breaker. Once you've identified the AC breaker, switch it off, wait at least 30 seconds, then switch it back to the "on" position.

Why is My Lennox AC Not Working?

If your Lennox AC is not working, it might stem from power-related problems rather than the air conditioner itself.

It could be due to a power outage, a tripped breaker, or other electrical issues in the breaker box.

For any electrical concerns, it is crucial to consult a licensed electrician, as attempting DIY solutions without proper knowledge can be dangerous.

However, if the issue is with the air conditioning unit, it's best to contact an HVAC professional.

You might also like: Why Won’t My Lennox Air Conditioner Turn On?

Repairman works on air conditioner horizontal shot

Is Lennox HVAC Reliable?

Lennox air conditioners are known for their reliability when adequately maintained.

Since so many parts could cause an issue, it's very important to have them checked regularly for any problems.

Again, if you notice a problem with your Lennox AC unit, you will need to contact a Lennox HVAC professional as soon as possible.

What is the Average Life of a Lennox Air Conditioner?

The average lifespan is around 15-20 years, which is what it takes to get a new Lennox AC unit under normal circumstances.

However, some homeowners choose to replace them before the 12-year mark to upgrade to a more efficient and powerful model.

Related content: How Long Does A Lennox Air Conditioner Last?

HVAC air conditioning unit on concrete slap with new construction brick house

Lennox Air Conditioner Troubleshooting Guide

Below is a troubleshooting guide to help you identify and address the most common problems with your Lennox unit.

1. Air Conditioner Not Turning on

If your Lennox AC unit is not turning on, try the following steps:

  • Check the power supply: Make sure the unit is plugged in and check that the circuit breaker hasn't been tripped. If it has, reset the breaker as needed.
  • Examine the thermostat: Verify that the thermostat has been set to cooling mode, and the temperature is set below the current room temperature.
  • Inspect the air filter: A clogged filter can obstruct airflow and cause the unit to shut down. Clean or replace the air filter at least once every 30 days.

2. Unit Not Cooling Properly

If your AC unit is not cooling as expected, consider the following troubleshooting steps:

  • Clean the condenser coils: Dirty coils hinder heat exchange and cooling efficiency. Clean the coils with a soft brush or gentle stream of water.
  • Check the refrigerant levels: Insufficient refrigerant levels can cause poor cooling. Speak to a professional, if you suspect any leaks.
  • Assess the thermostat calibration: An incorrectly calibrated thermostat can result in temperature discrepancies. Recalibrate it or replace it if necessary.

3. Strange Noises

Unusual noises coming from your Lennox AC can indicate various problems:

  • Rattling: Loose parts, debris, or a misaligned fan blade can cause a rattling noise. Secure any loose components and clear out any debris.
  • Hissing: A refrigerant leak may produce a hissing sound. If you hear hissing, turn off the unit and contact an HVAC professional.
  • Buzzing: Electrical issues, such as a malfunctioning contactor or capacitor, can result in buzzing noises. When this happens, refer to an expert.

4. Short Cycling

If your Lennox AC is frequently turning on and off, it may be short cycling due to the following factors:

  • Oversized unit: An improperly sized AC can cool the area too quickly, causing frequent on/off cycles.
  • Dirty air filter: A clogged filter can impede airflow, leading to short cycling. You'll need to replace the filter to improve airflow.
  • Low refrigerant levels: Insufficient refrigerant can cause the compressor to overheat and shut down. Address any leaks and recharge the refrigerant.

5. Water Leaks

Water leaks from your Lennox AC can result from:

  • Clogged drain line: A blocked drain line can cause water to overflow from the drain pan. Clear out any obstructions in the line.
  • Frozen evaporator coils: Insufficient airflow or low refrigerant levels can result in evaporator coils freezing, leading to leaks when the ice melts.
  • Incorrect installation: An improperly installed unit may have uneven leveling or incorrect drainage, causing water to pool.

You can learn more about troubleshooting your Lennox unit by watching this video.

You can also follow our guide on Lennox Air Conditioner Troubleshooting for a more comprehensive discussion.

Final Thoughts

Resetting a Lennox air conditioner is straightforward, though finding a conventional reset button may not always be the case.

By following the steps in this article, you can easily troubleshoot your Lennox AC unit.

If you're still experiencing problems, it's crucial to consult an HVAC professional or licensed electrician, depending on the issue.

We'd love to hear your thoughts on this article, so please feel free to share your feedback with us!

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