How to Reset Lennox Outdoor Unit: A Comprehensive Guide

Resetting a Lennox outdoor unit can be a straightforward process, but it’s essential to understand the underlying mechanisms and potential issues that may arise. This comprehensive guide will walk you through the step-by-step process of resetting your Lennox outdoor unit, providing detailed technical information and expert-level insights to ensure a successful reset.

Checking the Power Source

The first step in resetting your Lennox outdoor unit is to ensure that the unit is receiving power. This can be done by checking the power source, which may be a switch or a circuit breaker.

If the unit is connected to a switch, turn the switch off and then back on again. This will reset the power supply to the unit and may resolve any power-related issues.

If the unit is connected to a circuit breaker, check the breaker to see if it has been tripped. If so, reset the breaker by switching it off and then back on. This will restore power to the unit and allow you to proceed with the reset process.

Clearing Ice and Snow

how to reset Lennox  outdoor unitImage source: Lennox Ac by Raysonho

If the Lennox outdoor unit has been covered with snow or ice, it’s essential to clear it off before attempting to reset the unit. Ice and snow can interfere with the unit’s sensors and prevent it from functioning properly.

Use a broom or a soft-bristled brush to gently remove any accumulated snow or ice from the unit. Avoid using sharp objects or applying excessive force, as this could damage the unit’s components.

Resetting the Indoor Unit

The Lennox outdoor unit is controlled by the indoor unit, so resetting the indoor unit is a crucial step in the reset process.

Locate the circuit breaker or fuse box that supplies power to the indoor unit. Look for a breaker or fuse labeled “heat,” “A/C,” “furnace,” “blower,” or something similar. Reset the breaker or replace the fuse if necessary.

Once the indoor unit has been reset, you can proceed to the next step.

Resetting the Pressure Switch

The pressure switch is a safety feature that shuts off the Lennox outdoor unit if the pressure inside the unit becomes too high. To reset the pressure switch, locate the switch on the unit and press the reset button.

The pressure switch is typically located on the refrigerant line or the compressor. Consult your Lennox unit’s manual or contact a professional technician if you have trouble locating the pressure switch.

Using the Reset Button

Some Lennox outdoor units have a dedicated reset button on the control panel or on the unit itself. To use the reset button, locate it and press and hold it for a few seconds until the unit resets.

The reset button may be labeled “Reset” or may have a similar designation. Refer to your Lennox unit’s manual or contact the manufacturer if you’re unsure about the location or function of the reset button.

Waiting for the Unit to Start Up

After resetting the Lennox outdoor unit, wait a few minutes for the unit to start up again. The unit may take some time to initialize and begin operating normally.

If the unit still doesn’t start after a few minutes, there may be a more serious issue that requires professional repair. In such cases, it’s best to contact a qualified HVAC technician for further assistance.

Additional Considerations

Here are some additional tips and considerations to keep in mind when resetting your Lennox outdoor unit:

  1. Refrigerant Level: If the unit is low on refrigerant, it may not start up until the refrigerant level is replenished. This is a task that should be performed by a professional HVAC technician.

  2. Electrical Issues: If the unit is frequently tripping the breaker or fuse, there may be an issue with the electrical system that requires professional repair.

  3. Extended Downtime: If the unit has been off for an extended period of time, it may take a few minutes for it to start up again.

  4. Professional Assistance: If you’re unsure about any aspect of the reset process or if the unit continues to experience issues, it’s best to contact a qualified HVAC technician for further assistance.

By following the steps outlined in this comprehensive guide and considering the additional factors, you can effectively reset your Lennox outdoor unit and ensure its proper operation.


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