Capacitor & contactor replacement
If the outdoor unit hums but the fan won’t spin, a capacitor or contactor is the usual suspect. Replacing it is quick. Running on it until the compressor fails is not.
At a glance
Why this happens in Florida
The capacitor gives the compressor and fan motor the boost they need to start and run. It lives in the outdoor cabinet, and heat speeds the breakdown of the insulating film inside. Over time it drifts below its rated value.
The contactor is the switch that starts the outdoor unit. Every start makes a small arc across its contacts, and a long cooling season means thousands of starts. Insects, especially ants, also get into contactors and can keep the contacts from closing.
Summer thunderstorms bring power surges that can damage both parts. Heat pumps run in winter too, so their capacitors and contactors see even more cycles.
Why not keep resetting it
When a capacitor is weak, the compressor may not start. It sits drawing very high current until its internal overload trips, then tries again. Each attempt heats the motor windings, and repeated cycles can damage the compressor.
If the fan isn’t spinning but the compressor is running, the outdoor coil can’t shed heat. Pressures and temperatures climb fast.
Please don’t push the fan blade with a stick to get it going. Capacitors can hold a dangerous charge even with the power off.
What we check
Sometimes a failed capacitor is a symptom. A fan motor with worn bearings or a compressor that starts hard will wear out a new capacitor too, and the readings show which one you’re dealing with.
You see the meter readings before any part is replaced.
How the job runs
Call (904) 467-1100 or book online, and tell us whether the unit hums, clicks, or trips the breaker.
The diagnostic fee is $129 for homes, waived if you go ahead with a recommended repair over $250. Commercial is $149, waived on repairs over $300.
You get the price in writing first. After the replacement we recheck amp draw so you know the compressor is starting cleanly.
Related service
Straight answers
The outdoor unit hums but the fan won’t spin, the fan starts slowly, or the compressor tries to start and shuts off. A capacitor that is swollen on top is also a sign.
It can. A compressor that keeps trying to start on a weak capacitor overheats its windings, so it’s best to shut the system off and have it tested.
Heat speeds the breakdown inside the capacitor, and long cooling seasons mean many start cycles. Heat pumps add winter cycles on top of that.
Capacitors can hold a dangerous charge even with the power off, and the replacement has to match the rating. It is safer to have a licensed technician test and replace it.
Langston’s Heating & Air Conditioning · Licensed CMC1251311 · Mon–Sat 8 AM–8 PM
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