If your outdoor unit isn't turning on, then the air conditioner will not be able to remove the excess heat, limiting the amount of heat the refrigerant can absorb from inside the home. Ultimately, if the issue is not resolved, the air conditioner will no longer cool the home. Use this guide to find out some of the top reasons why the outdoor AC unit is not turning on.
Outdoor Unit or Thermostat Is Off
One of the most obvious reasons why the outdoor AC unit is not turning on is that the outdoor unit or thermostat is turned off. Similarly, if the thermostat setting is higher than the current temperature indoors, then the air conditioner will not turn on.
This is an easy fix. Just turn on the thermostat if it isn't already, set the temperature to the ideal level, then turn on the power switch for the outside AC unit, which can typically be found in a metal box close to the unit. If the thermostat still won't turn on, it may need new batteries.
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Power Interruption
If the power to the air conditioner is interrupted, then the air conditioner will not be able to function. Power interruptions can be caused by a tripped circuit breaker, blown fuse, damaged wiring, or faulty contactors.
A tripped circuit breaker or blown fuse is easy enough to fix, just flip the circuit breaker back to the on position, or replace the blown fuse to restore power. If the air conditioner problem is due to damaged wiring or other issues, contact an HVAC professional to repair the wiring or replace the any parts needed.
Worn Out Fan Motor
The fan on an air conditioner is designed to remove heat, releasing it into the open air. Unfortunately, the fan motor can wear out over time, causing the outdoor unit to seem like it has stopped working, even when the inside AC unit is on.
Typically, a fan motor will last between 10 to 20 years with proper care, but if your fan motor burns out, then you will need to hire an HVAC professional to come replace the fan motor.
Seized Fan Blades
A fan motor doesn't usually just stop working, but there is often some type of resistance that is causing the fan motor to overwork, overheat, and eventually burn out. A common issue is debris buildup around the axle of the fan. Twigs and leaves can become trapped in the axle, causing the fan blades to seize. If you notice this issue before the fan motor burns out, it's relatively easy to fix.
Just turn off the AC, remove the protective cover to access the fan, then pull out any debris or other obstructions that may be preventing the fan from operating normally. Turn the AC back on and test the fan. If it is still not rotating properly, then you may need to call an HVAC professional to assess and repair the issue.
Faulty Capacitor
Capacitors are responsible for the initial start up and ongoing operation of the fan motor. If the capacitors are not working properly, then the fan may not turn on or may not stay on.
Because this is a complex repair, hire an HVAC professional to inspect and replace the capacitors if you suspect that they are causing the problem with the outdoor AC unit.
Engaged Safety Switch
Air conditioners use a drain line to get rid of any excess condensation. However, if the drain line is clogged, then it can block the flow of condensation, causing the water to drip into the drain pain. HVAC systems often have a safety switch or float switch that will turn on when the drain pan is full of water. This is to prevent the water damage if the pan overflows. If the safety switch is engaged, the AC unit will not work.
Empty the drain pan and check the drain line to ensure it isn't clogged, then turn the safety switch off to restore the function of the AC unit. If the issue persists, call an HVAC professional to assess and repair the problem.
FAQ
How do I reset my outside AC unit?
The outside AC unit can be reset using the small, red reset button that can be found on the exterior of the unit or behind a service panel. Simply push and hold the button for several seconds to reset the unit. Alternatively, you can reset the unit by turning it off at the breaker panel.
Do outdoor AC units have reset buttons?
The outdoor unit on a typical whole-home air conditioning system will have a reset button. This button is generally red and easy to spot, though there is a chance that it's located inside the unit, behind a service panel that may need to be removed with a screwdriver for access.
How do I know if my outside AC unit is working?
Air conditioners have many different parts that you will need to inspect to verify that the outside AC unit is working. This should include a full inspection of the blower, fan, compressor, drain line, and capacitor. If the outside AC unit is working properly, the compressor and capacitor will help to power and control the operation of the blower and fan, which should then work in tandem to remove heat, while the drain line handles any excess condensate.
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