[Richard]

So, those readings are amperage draw for the three compressors on your coach?

Hard to tell anything when it’s cold just by the compressor amp draw.

The Dometic systems have ports if you have gauges or can get your hands on a set. The high side will not have insulation on the line, the low side will have insulation on the line.

[Georgeb]

Yes that is the amps for each unit
I may have a gauge set

Think I’ll wait for it to warm up
Thanks for the help

[Richard]

Just for grins, where are you and the lovely Miss Phyllis for the winter?

If you have some gauges, the big question is always, what should the pressures be? And the answer is always from an AC Pro, it depends. Well, it does depend. It depends on the outside temperature, the inside temperture, and the humidity.

In a case like yours, I use the two running units as a benchmark. What are their low and high pressures? Then I will compare the non functioning unit with the two good ones.

And as you said, you have to wait till you get at least into the 70’s for any reading to make sense.

[Georgeb]

After Thanksgiving we headed to Galveston. We have grandkids
In League City.
We spent lots of time setting on the beach, great weather.

Thinking about Tucson for February

[Richard]

Well, that's a bit far for swinging by Inverness, Fl.

[BusNit]

Reviving an older thread as my middle basement a/c stopped blowing cold air although both in and out fans were running. Today after leaving it off for a couple hours, I turned it on. It ran blowing warm air for a minute and then the outside compressor kicked in. Sounded normal but tripped the breaker. Where should I start looking? Worked fine the last couple of days I ran it. Thanks guys!

[Richard]

I think you have the Dometic units, which are a type of mini split.

The most common failure is the outside fan stops working, the compressor head pressure goes high, and the breaker trips. So, first of all, confirm the outside fan is working.

If it is working, then locate the compressor wiring either at the outside unit, or inside the silver control box mounted on the inside unit. It is oddly shaped and usually secured with a large rubber strap. Inside that control box you will see a circuit board, and one of the relays on the circuit board will have wires coming out of the top of it. In either place, hang an ammeter on the wiring and report what it does.

1. Goes to locked rotor amperage right away, and breaker trips
2. Spikes, compressor starts and amperage slowly climbs until breaker trips
3. Something else

If it is not the outside condenser fan, than it could be as simple as the start capacitor on the compressor, or something more sinister like a fried compressor.

While you are nosing around in the silver control box, a number of owners including me, have found the twist on connectors where the power is fed into the control box have worked loose over the years and caused a poor connection. When I had a coach with that AC system, I found two almost fires where the connection had heated to the point of melting the insulation pretty far down the wire. I personally would go ahead and modify those connections using Alumaconn connectors. I am a big fan of bulletproofing the high amperage wire connections. Not cheap, but oh so robust. https://www.amazon.com/King-Safety-95104...132&sr=8-6

I think you are an electrical contractor, so you may have even better solutions.

[BusNit]

Thanks Richard! I will start the hunt soon. Trying to get as much done inside so I can shove off more blank slates to the upholstery shop while he is still taking in my work. As you may know, I have been soldering every possible connection I can get my hands on both high and low voltage. My fear is a fire loss. I have put so much money in this so far. Appreciate the heads up on the power connection for the units. Those too will probably get some solder on them as well! LOL

Ironically, I have about 30 of those alumaconn connectors. We do not touch aluminum wiring at any job and use those as a "favor" to those contractors we actually trust. Too much liability. Copper circuits or we do not take the job.

[BusNit]

Crap. Got home to find the coach sweltering. Front and rear ACs were not running. Front salon unit had red LED flashing twice with a pause in between. That one has the old manual thermostat. Bedroom has a newer digital dometic thermostat and did not reveal any codes. Frustrating

[BusNit]

Richard, I finally got around to checking out why the middle ac was blowing the breaker. Unit pulls 18.9 amps and then starts going up from there. I went outside and heard the fan motor clanging around. Compressor was running and sounded normal. This morning I found that the rear bedroom AC died and probably overnight. It is the only one of the three with a digital thermostat. I could not get it to turn on by the buttons or even resetting the breaker. Today I bought a portable inverter ac unit and as I was setting it up, the rear bedroom unit mysteriously powered itself up and began working. I hadn’t made it to the control box yet to see if there was something failing in there.

So anyway my question is how do I remove the top unit to get to the fan motor? The shelf it’s sitting on needs to get replaced too.

Thanks!