If your outside coil (also known as the condenser coil) is not running while the AC unit is operating, there could be several possible reasons for this issue. Here are some common causes:
Thermostat settings: Check your thermostat settings to ensure that the cooling mode is active and the temperature is set lower than the current room temperature. If the thermostat is not calling for cooling, the outside coil may not start.
Tripped circuit breaker or blown fuse: A tripped circuit breaker or blown fuse can disrupt the power supply to the outside unit, causing it not to run. Check the electrical panel and reset any tripped breakers or replace blown fuses.
Thermostat malfunction: The thermostat may be malfunctioning and not sending the proper signal to start the outside unit. Test the thermostat by setting the temperature lower than the current room temperature and checking if the outside unit starts.
Faulty contactor: The contactor is an electrical component inside the outside unit that allows power to flow to the compressor and the condenser fan motor. If the contactor is faulty or worn out, it may not engage, preventing the outside unit from running.
Defective capacitor: The capacitor is responsible for providing the initial jolt of electricity to start the compressor and the fan motor. If the capacitor is faulty or has failed, the outside unit may not start.
Low refrigerant level: If the refrigerant level in the system is too low, the air conditioner may not be able to build enough pressure to start the outside unit.
Blocked condensate drain: If the condensate drain is clogged, it can trigger a safety feature that prevents the outside unit from running.
Faulty fan motor: If the fan motor in the outside unit is malfunctioning or damaged, the condenser fan won't run, and the outside coil won't receive proper airflow.
Due to the complexity of diagnosing and repairing air conditioning systems, it is often best to have a qualified HVAC technician inspect and troubleshoot the problem. They have the necessary tools and expertise to identify the issue and perform the required repairs safely. Additionally, attempting to troubleshoot and fix complex HVAC issues without proper knowledge can lead to further damage or safety hazards.