Central Air problems - circuit breaker needs to be flipped constantly?

Question

My outside Central Air unit won't start unless I flip the circuit breaker off and on. And then after about an hour, it stops working and I have to go downstairs and flip the circuit breaker off and on again. Any ideas on the problem? I have already changed the outside fuses and the thermostat.

Answer 1

Do you have a Carrier unit by chance? This would seem to be a problem related to a lock out device. Carrier often incorporates a compressor logic board in their condensing units. It locks out the unit from starting through a low voltage relay, and can only be reset by shutting off the main switch, or actually turning the thermostat off and then back on. The next time it happens, see if you can reset it from the thermostat. If you have a Payne, Bryant, or Day & Night unit, you may have the same device as they are all now owned by Carrier. The board can be identified by tracing the leads of the compressor. One of them will run through a ring on the board. Check all of your wires in the unit. Turn off the power. Make sure all of the wiring connections are tight. Insure that no wires have been rubbing to where the insulation on the wire is to the point of exposing bare wire. Check the wiring for evidence of being too hot. If it continues, you'll need to call an HVAC tech.

Answer 2

so you are not tripping the breaker, but instead are cycling power to the unit to "reset" it? if thats right it sounds like the condensing unit has a lock out built in

If it's a carrier it may have a "CLO board" this will hold the system off if one of the safety's have tripped, being that it's summer and it is hot, it's likely the Condensor Coil could be dirty and it's tripping the Hi-pressure safety switch which is then causing the unit to lock out until power is reset.  You can clean the condensor yourself with the garden hose, just be sure to shut power off to the unit before you start.

send me a message if you need further help..

Answer 3

It sounds like you have a short or the motor has gone bad, call a repair man.

Answer 4

Sounds like the condenser (outside unit) is plugged up.  The dirty condenser can and will cause compressor to work harder, drawing more amps and tripping the breaker.  Since the unit runs for an hour before tripping, a good condenser cleaning should cure it right up.  Turn off power, and give it a good flushing with a garden hose, being careful not to bend the aluminum fins over with the water pressure.  After hosing it out, let it sit a few minutes and power it up.....I'll bet that'll do it for ya.

Good luck.

20+ yrs hvac tech

Papa C. The clo board you're speaking of won't cause the breaker to trip...it only opens the control circuit.  ....Which begs the question of HAL, are you turning the breaker off , then back on, or resetting a tripped breaker.  Either way, if the clo board is shutting it down, it's just doing what it's supposed to do.  Again, cleaning the coils will drop amperage, and the clo board shouldn't trip.

Chuck P.   The fan motor may be bad, but usually when a motor overamps from worn bearings, it'll trip on it's internal overload and cause the unit to fail, usually in much less than an hour.  

Clean those coils!!!