What should I check before calling for AC repair?
Before calling, check that the thermostat is in cool mode with a low enough setpoint, the indoor air handler is running, the breakers for both the indoor and outdoor units are on, and the filter is not badly clogged. These simple fixes sometimes bring the system back.
Listen to what the system is doing. If the indoor fan runs but the outdoor unit is silent, the compressor circuit has a problem. If nothing runs at all, the cause may be a tripped breaker, a dead thermostat or a float switch shutting the system down.
Give the system a few minutes after changing settings. Many units have a built in delay that stops the compressor from restarting immediately, which protects it from damage after a short power interruption.
Why would a compressor not start even though the fan runs?
A compressor that will not start while the outdoor fan runs usually points to a failed start or run capacitor, a worn contactor, or a safety switch that tripped. A seized or failing compressor is less common but more serious. Each needs an electrical test to confirm.
Capacitors are the usual suspect in Arizona because heat wears them out. A weak one may hum or click without starting. A contactor with pitted contacts can fail to pass power. Both are routine repairs for a licensed AC technician when diagnosed correctly.
A high or low pressure switch can also lock the compressor out. That often signals a deeper issue, such as a dirty condenser coil, restricted airflow or low refrigerant, so resetting the switch repeatedly is not a fix.
Is it safe to force the compressor to start myself?
Forcing a compressor to start is not safe. Pushing the contactor closed or jumping the unit can burn out the compressor, damage the control board or shock you, since the outdoor unit carries high voltage even when the cabinet looks quiet. Shut the system off and call a licensed tech.
Capacitors can hold a dangerous charge even after power is switched off. That is one more reason the outdoor electrical compartment should stay closed unless a trained technician is working in it.
A unit that keeps trying to start also makes damage worse. Turning the thermostat to off protects the equipment while you wait for service, and you can use fans to stay more comfortable in the meantime.
What does a compressor problem cost me if I wait?
Waiting on a compressor problem can turn a small repair into a large one. A bad capacitor is a minor part, but running the compressor on it strains the motor. Catching it early often saves the compressor, which is the most expensive part of the system.
In summer, a home with no cooling heats up quickly, and attics and slab floors hold that heat into the night. Vulnerable people such as young children and older adults are at real risk, so do not tough it out.
Vortech is licensed for air conditioning and electrical work and is open 24 hours per its Google profile. Use the call button on this page when your system will not start and you want a technician to look at it.
More questions: AC Repair: 12 Most Asked Questions Answered