[Richard]

Brad,
The best bet is to see if it has a number or manufacturer on it. Plug that into google and see what you get.

That's the way I found replacement relays for the boards.

[Brad Townsend]

Yup google it! That's what I tell folks.
So I am a bit confused about the circuit board.
I don't see one. Am missing something?
Brad

[Richard]

I don't know, my 95 with Dometic units had circuit boards at each air handler.

Owners of earlier Dometic setups should weigh in here cause I may be providing bad info.

[ccjohnson]

I don't know, my 95 with Dometic units had circuit boards at each air handler.

Owners of earlier Dometic setups should weigh in here cause I may be providing bad info.

I can post a couple of pics of the control boxes located inside under our dinette benches when I get home. May be a couple of days though.

[77newell]

My 93 with Dometics had the circuit boards in a metal box at each blower motor and evaporator (the box inside the coach).

I'm coming late to this party (been hanging out with Richard), but I wonder what happens with the condenser fan if you were to disconnect the compressor motor from the circuit and just let the fan motor run. Does it then shut down in 5 minutes or does it keep running and at what amperage. The question I'm trying to resolve is does the fan spontaneously stop and then the compressor shuts down or is the compressor causing the fan to shut down which then causes the compressor to overload. If it is the latter, then I suspect something unintended changed in the electricals when the compressor was changed.

[folivier]

Jon your a/c circuit boards are the upgraded digital version to go along with the digital thermostats.
Richard may possibly have an original board or two.

[Richard]

Forest,

I passed them on to another guru.

[hexspeed]

I'm not a Guru, but have been reading circuit diagrams and fixing stuff like this for many years.

IF the diagram provided is accurate, both the compressor and fan SHARE the hot (black) lead. That means if there were an "upstream" problem in the contractor / circuit board / etc., it would shut down BOTH of them, not just the fan. I think Jon is on the right track by seeing what happens with just the fan running.

If I were a betting man, I'd put my money on the fan motor getting too hot and tripping an internal (to the motor) overheat switch. While the fan is off and cooling down, the compressor overheats and shuts down. Wait for both to cool and their respective overheat switches to reset, and you can start the cycle all over again.

So, why is the fan acting up now? 1) Crap knocked loose during the compressor relacement getting sucked into the motor's cooling ports? 2) Motor was running "hot" before but not enough to trip the overheat, and the new compressor is making the box environment just enough hotter to cause the overheat? 3) Airflow through the box was compromised during the repair so it's now just too hot for the motor to stay within operating specs? 4) Bearings going bad so motor is working too hard?  Take your pick, but I think it is ultimately temperature / cooling related.

Only other wild card is an electrical connection to the motor that is failing when it gets hot. Low probability in my mind since these problems tend to get worse pretty quickly, and you're reporting a failure that can be repeated with a predictable pattern.

OK! I'll go back to lurking now ...

Jim
Newell Coach Fan

[Brad Townsend]

Jon, yes the fan stops then the compressor stops from getting to hot within about a minute or two. The Amperage stays the same about 2+ and never spikes prior to shutting down.

Jim,I thought about stuff getting into the ports during soldering etc as there was a bunch of soldering taking place with different size tubing to get the right size to fit BUT wouldn't that cause the compressor alone to overheat and quit, leaving the fan to continue to run?

The compressor was wired backwards initially producing heat inside the coach instead of cold, i think that is what happened to the capacitor in the box inside the coach. You can see the top blown out. But it still ran and the capacitor was replaced. 

Brad

[77newell]

Brad: yes, I recognized the order of shutdowns, my proposal was to electrically disconnect the compressor motor while leaving the fan electrically connected and then turning on the thermostat to cool. The fan should come on and stay on unless it is by itself shutting off (that is without being effected by the list of heat adding conditions Jim listed). I would want to know the fan motor is or is not working fine all on its lonesome.