AC Still not working---Update---

If the compressor is seized I would expect the breaker to trip

One more test you might try is to disconnect both motor leads and ohm out the motor making sure the motor is not open.

darsben1 wrote:
If the compressor is seized I would expect the breaker to trip

Yes, the breaker trips but it is confusing to me because sometimes the breaker at the source trips and sometimes the breaker in the trailer panel trips.

Have you measured amps and volts during the event?
Otherwise you may as well take it in to the shop.

Mandalay Parr wrote:
One more test you might try is to disconnect both motor leads and ohm out the motor making sure the motor is not open.

If seized thermal overload opens in most cases so appears as an open winding. If tripping breaker then you need to check if compressor windings now have continuity to GND & you need an ohmmeter that has MEG-ohms range .
You might get lucky & just be loose connection at breaker.

What difference does it make which breaker trips first...you have a short to ground somewhere as a 15A unit should not trip a 30A breaker when it tries to start. While it's not likely the short is in the board I would pull one of the wires going to the compressor and see if it still trips the breaker before replacing the entire AC.

This is a 15,000 BTU, not a 15 Amp unit. We have one, and it's on a 20A circuit within our RV panel, 30A coach.

The question seems to be: Is the Compressor Locked (Stuck)?

There are three Amperages related to a compressor:

Starting, AKA Peak Inrush. This could be 50A or more and it takes good equipment to measure it. My cheapie Horror Fright clamp-on AC Ammeter cannot capture that.

Running, probably around 10-12A. Cheapie WILL capture that.

LOCKED ROTOR AMPS, Along with Running Amps, will be on a plate or label on the Compressor. LRA for this Mach 15 A/C is probably around 50A. Cheapie WILL capture this amperage.

But what usually trips on LRA, is an INTERNAL cutoff within the Compressor.

IF IF IF the RUN Capacitor is bad, Compressor will go into LRA and trip off on the internal protection. Very many tries, the Compressor will get HOT and it takes a LONG time, say half an hour, to cool enough for another try.

So, I recommend this: Disconnect Power and let the compressor cool while you get an Ammeter. Then, be on the roof, at the compressor, Ammeter clamped on input power, and have a helper turn the system ON. See what the Amps are. IF it's LRA, you have only seconds to read it before the internal trips the power off. You want to be on a full power shore tie, no extension cords. Give the Compressor its best chance to start.

Possible Hail Mary: I've seen this work, albeit rarely. Compressor COLD. Again, on max available AC power: Same as the AMPS test, but this time you're next to the Compressor with a RUBBER MALLET. Line up a clean shot at the upper end of the Compressor where you won't hit a line, wiring or component. Have your assistant turn the system on and Smack the Compressor a split second later, before the internal will open the circuit. As I've said, odds are against this but I've seen it work. Odds? My speculation is 5-10 pct. But it's sure a cheap try.

I recommend you clean the condenser coils, carefully straighten any that may be bent. A clogged condenser overworks the compressor which increases the amperage draw - thus blowing the breaker.

talotto wrote:
I recommend you clean the condenser coils, carefully straighten any that may be bent. A clogged condenser overworks the compressor which increases the amperage draw - thus blowing the breaker.

The cooling fins are clean and in near perfect condition. I believe that the compressor is frozen as it wont start when system is turned on.

then time for a new ac unit
It is an easy do it yourself job the hardest part will be getting the unit onto the ROOF.
shop around prices run from about $650 to $800 for the Coleman 48204C866 unit
I happened to see that PPL has it for $620.00 delivered.
http://www.pplmotorhomes.com/parts/rv-air-conditioners/coleman-rv-air-conditioning.htm