If the outside coil (condenser coil) of your AC unit is not running, there could be several reasons for this issue. Some of the common causes include:
Thermostat Settings: Make sure that your thermostat is set correctly and is calling for cooling. If the thermostat is not set to "cool" or if the temperature setting is higher than the current room temperature, the outside coil may not run.
Tripped Circuit Breaker: Check your circuit breaker box to see if the circuit that supplies power to the AC unit has tripped. If it has, reset the breaker and see if the outside coil starts running again.
Disconnected Power Supply: Ensure that the AC unit is receiving power. There may be a disconnection in the power supply, a faulty power switch, or a blown fuse in the disconnect box near the condenser.
Faulty Capacitor: The capacitor is a component that provides a boost of electrical power to start the compressor and the fan motors. If the capacitor is faulty, it may prevent the outside coil from running.
Failed Contactor: The contactor is an electrical switch that controls power to the condenser unit. If the contactor has failed, it may not be sending power to the outside coil.
Faulty Compressor: A malfunctioning compressor can lead to the outside coil not running. If the compressor is not working, it won't be able to circulate refrigerant through the system.
Low Refrigerant Level: If the AC system has a refrigerant leak, it may result in low refrigerant levels. This can cause the outside coil to freeze up and prevent it from running efficiently or at all.
Blocked Airflow: Obstructions around the outside unit, such as debris, leaves, or grass, can block the airflow to the coil, causing it to overheat and shut down.
Faulty Thermostat or Wiring: A malfunctioning thermostat or damaged wiring between the thermostat and the AC unit can disrupt the signal to the outside coil, preventing it from running.
It's important to note that diagnosing and fixing AC issues can be complex and may require the expertise of a trained HVAC technician. If you are not familiar with HVAC systems or electrical work, it's best to contact a professional to inspect and repair your AC unit safely.