A/C runs cold, kicks out breaker

[werpknarly]

1979 international, original a/c.. it starts up fine, runs 15-20 secs i think... blows COLD air. then trips the breaker.. had the local rv place look at it a couple of years ago. stumped them.. i assume then its doing this while plugged into suffenct electrical supply.

any ideas ?

[HowieE]

The first thing I would check is the breaker. Get a clip on amp meter and watch it as you turn on the AC. If the current remains Below 12 or 13 amps and the breaker trips I would change the breaker. If the current steadily rises till the breaker trips I would clean the coils. Clean both the evaporator and condenser coil.

You should be able to get coil cleaner at the Big Box Store. If not try Simple Green.

[SteveH]

Bad breaker?

[Jammer]

Well there are really only three ways this can go.

1) Bad breaker
2) Thermal protection on compressor jammed and compressor windings shorted
3) Thermal protection on compressor jammed and high head pressure due to no airflow over condenser coils.

So the first lo-tech thing to do is go up on the roof and pull the cover off and see if there's a mouse nest or leaves or dirt up there blocking the coils, or maybe the blower wheel or fan blade (as the case may be) is broken off the shaft. All that's a fairly easy fix.

If you don't want to go up on the roof and you have an ammeter you can get a good idea whether that's the problem by watching the current, if after the first half second or so it settles down to around 18 amps then rises gradually up to 25 or so then trips well probably you have a mess up there on the roof.

If everything looks great up on top then its time to get out the ammeter anyway and see how much current is actually flowing. For the breaker to trip that quickly it would have to be at least 25 or 30 amps, if less than that, well probably a bad breaker.

If the coils are clean, the fan blows air across them, and you're still drawing more than 25 amps, especially if it starts at around 25 amps and stays there or maybe jumps around on the meter kinda at random, well, sorry, start saving up for a new A/C.

[werpknarly]

breaker is good.. everything clean.

[TG Twinkie]

I think it is a problem with not switching from the start winding to the run winding. Could be a bad relay or capacitor.

[HowieE]

Originally Posted by werpknarly

breaker is good.. everything clean.

How did you decide the breather was good? Swap it out with another or current test?

[werpknarly]

been over a year since we looked at it.. i know i tested it, my dad tested it, RV dealer tested it.. so im 99% sure its not breaker..

[werpknarly]

Originally Posted by TG Twinkie

I think it is a problem with not switching from the start winding to the run winding. Could be a bad relay or capacitor.

our thoughts too.. which/how do we test ? i might be open to just buying new ones vs cost of professional help.. "replace A/C" is the help ive gotten so far

[HowieE]

Originally Posted by werpknarly

been over a year since we looked at it.. i know i tested it, my dad tested it, RV dealer tested it.. so im 99% sure its not breaker..

Swap the breaker with another in the trailer. Do you know anyone that was in good health last year that is gone now? When testing electronics you never accept yesterdays results. If it a simple thing like swapping out a breaker that may save you lots of money do it again.

[Alphonse]

What size breaker is it tripping? 20 amps? The service feed or the one in the trailer. I am assuming you are talking about the one in the trailer. Breakers that have been tripped multiple times should be replaced.

FYI, Just had an electrician put in a plug for me for my AS which has a 15k BTU AC on it. We clamped an ammeter on the service and we watched the amps and it never exceeded 16 amps to my surprise. It is only 2 1/2 years old and has a soft start feature to it.

I am with HowiE on this, suggest you try changing the breaker first.

[68 TWind]

You do have the trailer plugged into a 30 amp circuit and a short cord. Make sure your voltage is over 110V. Harbor Freight has a clamp on ammeter for a low price. I would check voltage first and then current draw on start up. Watch the current draw when it kicks off.

[Bill M.]

Mine did that. In fact it would sometimes run for half and hour or so The it would not run at all. Technician cleaned unit at top, muttering under his breath, and changed a capacitor. Works fine now.

[werpknarly]

i do wish people would read. three people who know how to test AND changed brakers did that. YES ALL three of us have 30amp service and large short cords.. which capacitor can i change ?

[68 TWind]

Great attitude, I see you appreciate the comments of folks here trying to help you.

[SteveH]

There are two capacitors up there. One is the start capacitor, and the other is the run capacitor. Since your unit seems to work OK on start up, I would change the run capacitor, and see if that helps. If you have the paperwork on the unit, the capacitors will be designated in there.

[HowieE]

Originally Posted by werpknarly

1979 international, original a/c.. it starts up fine, runs 15-20 secs i think... blows COLD air. then trips the breaker.. had the local rv place look at it a couple of years ago. stumped them.. i assume then its doing this while plugged into suffenct electrical supply.

any ideas ?

Best of Luck. We assumed nothing only took what you posted as the bases for our comments.

[Alphonse]

Originally Posted by werpknarly

i do wish people would read. three people who know how to test AND changed brakers did that. YES ALL three of us have 30amp service and large short cords.. which capacitor can i change ?

Apologies that I didn't get that from your earlier posts.

Good luck to you.

[werpknarly]

Originally Posted by SteveH

There are two capacitors up there. One is the start capacitor, and the other is the run capacitor. Since your unit seems to work OK on start up, I would change the run capacitor, and see if that helps. If you have the paperwork on the unit, the capacitors will be designated in there.

thanks steve, i try to get some time to get under the hood