In the first instance you should locate the breaker that powers the system and turn it to the OFF position. Turn the switch back to the ON position to reset the breaker. Various AC unit malfunctions can be rectified by resetting the breaker. Occasionally the breaker can throw itself into the OFF position on the electrical panel.
It is easy to reset the breaker and this should be the first fault-finding task done. Notice a simple fault such as this on your air conditioning unit and you waste no money calling an HVAC contractor. However, breakers that pop and spark or breakers that immediately reset themselves back into the OFF position should be inspected by a licensed HVAC professional.
When the breaker has been reset ensure the thermostat is set to air conditioning and the fan is programmed to AUTO. At this point the ac unit may begin to function, if it doesn’t move on to examine other possible problems.
Some homeowners have a service disconnect switch placed within five feet of the outdoor ac unit. Open the switch panel and search for a breaker. Reset the breaker switch to see if it turns the system on. A number of outdoor air conditioning units have a red reset button on the external casing.
If this is the case press the red reset button to try to fix the problem. The panel itself will be filled with fuses; burnt-out fuses can be replaced at local hardware stores. If changing the fuses or resetting the system doesn’t fix the fault, shut the switch panel and move on to another fault-finding exercise.
The resets may not correct the fault. In this case you should ensure the air con unit is getting power. Check the wiring is in good condition, animals and insects can chew and damage ac casing. A transformer powers the low voltage circuit and this circuit is in the unit or inside of the central system.
Electrical issues must be dealt with correctly and safely, contact an HVAC service technician to rectify electrical faults.
Professional HVAC service technicians will test the circuitry and coolant and repair faults. We hope you have found our air conditioner thermostat troubleshooting guide useful, however, some air conditioning units develop major faults that can only be repaired by experienced ac technicians.