AC unit is blowing the breaker.. need ideas

[bobk]

The aft stateroom AC is popping the breaker on heat mode. It has worked fine for the 2.5 years I have had the boat. Control is after market digital electronic. I can't run from the breaker back to the AC control fast enough (3-5 seconds) to hit the off button before it blows again, so don't know if this is a heat-only problem.

Ideas anyone? I did a search of old threads but didn't find a similar problem.
This is a split unit, probably 1981 vintage about 9000 btu.

Bob

 

[Finalee]

A locked compressor will do that.

 

[BUSTER]

The aft stateroom AC is popping the breaker on heat mode. It has worked fine for the 2.5 years I have had the boat. Control is after market digital electronic. I can't run from the breaker back to the AC control fast enough (3-5 seconds) to hit the off button before it blows again, so don't know if this is a heat-only problem.

Ideas anyone? I did a search of old threads but didn't find a similar problem.
This is a split unit, probably 1981 vintage about 9000 btu.

Bob

I've had this happen several times over the years and it seemed like the compressor was indeed locked up.Once it happened on a unit less than 2 months old. Each time I freed it up by giving the compressor body a whack with a block of wood and a hammer as someone simultaneously threw the breaker on. Hope it works for you.

 

[krush]

could also be a bad breaker.

 

[Maynard Rupp]

The preassures may be too high usually caused by lack of cooling flow through the tubes from your sea water pump system. Clean your strainer on the intake to the water pump first but plan on having to clean your tubing with acid. We had this problem 2 months ago and hired an AC guy to clean the tubes. You should have seen the shells and crap that came out. When he was done, the high end preassures of both units came back into the normal range.

 

[Genesis]

If it is tripping immediately it is probably locked-rotor on the compressor and is toast.

If there's a water flow problem (pressure related) it usually takes 30 seconds or more before it will trip, but that usually doesn't trip the breaker, it trips the safety switches in the unit and shuts it down (it will then try to recycle)

My guess is that the unit has locked up - bad news if so, but its the most likely scenario.

Get a friend to stand next to the unit when you try to start it - if it hums and doesn't start, that's what's up.

 

[Pascal]

I agree with Karl, a water flow problem will take a little while and it wont trip the breaker anyway, the high pressure switch will trip and turn the unit off before the breaker can trip.

swap the breaker jsut in case, but unlikely. Or look at the amp meter, if you see amps spiking as thecompressor tries to start, then it's unlikely to be the breaker. If you try running that AC when on genny, if the compressor is locked you will hear the genny strugling before the breaker trips.

only thing you can try, is letting it rest for a few hours before trying it. that has worked for me in the past but eventually you'll have to replace the compressor. Especially if the unit was slightly overcharged.

one last thing, it could be the start capacitors. also unlikely but one thing to check just in case.

 

[rwetherington]

I would agree with the advise from above. Two more things to try unwire the compressor to make sure that you do not just have a wire that has shorted out, also does it do it in cooling? If it does it in cooling then you have a lock compressor. to fool the unit to go into cooling hold you hand on the sensor to get it to think that it is 80 degrees. if it is a lock or hard start compressor you may want to have a hard start kit installed to help out the starting of the compressor. If you need a HVAC tech and you are close to Jarrett Bay give me a call and I will send one by.

 

[krush]

These damn threads are deju-vu. I come in say check the cheap stuff first. Others come in and say it's locked rotor. Finally somebody says check the capacitors and starting circuit.

Do a search, I know i've posted a lot of HVAC info on these forums.

 

[Pascal]

not everybody is as smart as you are krush... pls try to be a little more understanding towards us mere mortals.

 

[thoward]

http://us.fluke.com/usen/products/F...FlukeUnitedStates&Category=CLMP(FlukeProducts)

Get a clamp on meter, start it up and see if it draws too much. That will point you in the right direction. If it draws more than the rated amount you need an AC guy. If not, you likely have a bad breaker. Like krush wrote, it could be the start capacitor, then again it could be a locked rotor. Either way it is best to let an AC guy fix it, those capacitors can bite you. With the breaker popping that fast I doubt it has anything to do with pressures but a set of pressure gauges is a good idea to have aboard.

 

[egaito]

not everybody is as smart as you are krush... pls try to be a little more understanding towards us mere mortals.

But it's just SO frustrating to be constantly surrounded by inferiors!

 

[Finalee]

Question. If the compressor will restart after being jarred by the impact from hammer to wood test. What are the odds it will relock?

 

[Genesis]

Extremely high.

BTW if it starts after being whacked its probably not the start capacitor

(Yes, that should be checked; they DO fail from time to time....)

 

[krush]

Chances are that it MAY lock back up, but there is also a chance it will keep ticking along. If you have to bang it with a block once a year, is it worth replacing? That's a personal question LOL I'd take giving it a wack once a year over replacing.