Weird A/C problem

[Tommy G]

We have a Frigidaire wall unit A/C (10,000 BTU, 110V/12A unit) that works fine, as long as we leave the thermostat turned all the way towards cold. If we set the thermostat higher, as soon as the desired temperature is reached and the compressor kicks off, we can tell by the sound of the unit that it begins to pull way more amps than it should, and the 20A circuit breaker on which it's located (the A/C is the only device on this circuit, by the way) trips off within a few seconds.

We're curious if anyone here has seen this problem before, and if it's likely to be an expensive fix. We don't mind just leaving the thermostat all the way down, so the compressor stays on all the time, but still, the circuit overloads are a bit disconcerting. We like to leave the A/C on while we're out of the house and are worried about a possible fire risk.

Thanks for any info.

[barry]

20a dedicated circuit for 10kbtu/h unit? What's it SEER? 3?

Seems very likely OP could make for huge jump in energy-efficiency.

HTH, J

[Edwin Pawlowski]

Could be the thermostat trying to re-stat the compressor. Normally, there is a differential of a few degrees, but if it is faulty, it may trip, try to re-start under pressure and trip the breaker. How old is the unit? Cold be as cheap to buy new as to fix.

[Doug Kanter]

Especially at this time of year. There are discounts all over the place on these things.

[~^Johnny^~]

[Tommy G]

Actually we double checked and it's 12000 BTU. And the circuit isn't dedicated, the A/C is simply the only device we currently use on that circuit (mainly because of the problem I described).

[Drifter]

Sounds like a bad relay and/or pressure valve/sensor (if it has one).

It sounds like the unit kicks off, and then tries to restart the compressor immediately. The internal pressure hasn't had a chance to bleed off so the compressor can't kick over but keeps trying (pulling a lot of power and probably making a low humming noise) until it pops the breaker. Eventually this will burn out the compressor motor. Drifter "I've been here, I've been there..."