Lennox brand air conditioners are available in a variety of sizes and with many different features, such as sound insulation, Energy Star rating, energy saving options, two-stage cooling, and even solar energy power usage. While the air conditioners are built to function properly for a prolonged period with only customary care and maintenance, all heating and cooling appliances are subject to occasional problems. If this occurs, performing some troubleshooting efforts on the air conditioner is relatively simple and may help identify the issue.
Ensure the air conditioner is plugged in to a working electrical supply if the air conditioner is not working. Replace or reset the fuse or circuit breaker if necessary.
Check to make sure the electrical disconnect switches on the unit are all turned to the "On" position if the unit is not operating but has power.
Turn the air conditioner thermostat to a temperature below the current air temperature if the air conditioner has power but is not turning on. The device will not function if the thermostat is set at a temperature above the current ambient temperature.
Remove the air filter and rinse with cold water if the air conditioner is not working properly. Air dry the filter completely before restoring in the unit. Ensure the front access panel on the air conditioner is firmly in place and the vents on the outdoor unit are free of grass, dirt or other debris. Clean as necessary with a clean cloth and rinse with clean water from a garden hose.
Contact an authorized service technician if the above steps do not resolve the issue.