How To Look At A House
McGarry and Madsen's home inspection blog for buyers of
site-built, mobile/manufactured and modular homes
My air conditioner outside unit (condenser) won't start and is making a humming noise. What's wrong?
Monday, August 6, 2018
The most likely problem is a capacitor that has gone bad. The electric motor which compresses the refrigerant flowing through your system requires an extra surge of electricity to start-up. A “starting capacitor” is a small metal cylinder that accumulates a electrical charge, then releases the additional jolt of electricity just as the motor first turns on. If it has gone bad, the humming sound you hear is the motor trying to start, but not succeeding in overcoming its starting inertia.
We recommend that you turn off the system to prevent any overheating damage until a service tech arrives and can troubleshoot the circuit to verify if the capacitor—or something else—is the culprit. Right now in our North Florida area a service call with a capacitor replacement will cost
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To learn more about heating and air conditioning systems, see these other blog posts:
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