Dometic 16kbtu Kicking Breaker

[Bob Bradley]

I have a 5 yr old (or so) Dometic replacement for my old Cruisair unit. Its been working fine until a recently when it began kicking out the breaker on the heat setting. AC seems to work fine. It is the split system that services the master suite and the V-Berth. Any suggestions would be appreciated.

 

[SEVEN]

Bob, I’d start with the breaker itself. I have had to replace some for the same reason. They are old and a bit weak. If that’s it, it’s a cheap fix. Hope that helps.

 

[Fanfare]

Cruisairs use more current making heat than they do to cool. Probably that little boost plus a tired breaker.

I seem to remember that I had to disconnect (unscrew) all the breakers in that row in order to replace just one. When I realized this I ran out and purchased all my other A/C breakers to replace all of them rather than do this again. They were always the ones that tripped most often and so probably wore out soonest.

 

[doc g]

I'd put an amprobe on it and check the amp draw before ripping into breakers ........Pat

 

[Bob Bradley]

The problem with checking the amp draw is that the breaker kicks just as soon as the compressor starts, so I can't really check it. The breaker that is kicking is in its own electrical box on the ER bulkhead, not in the main panel. There are 3 or 4 of these boxes, so as long as there is no serious corrosion, I should be able to swap it with one that is working ok.

 

[doc g]

I think u said it runs in cool mode , if it’s not too cold to get the compressor to run check the running amps while cooling. May also try disconnecting the reversing valve . Maybe the RV is shorted . Normally those are just a plug in socket, two wires. I suppose an over charged system is also a possibility as that would create a larger draw in heat mode than cool mode . Hope at least some of this is helpful .... Pat

 

[oscarvan]

My money is on the breaker. Do you have another one of the same value somewhere you can swap with for a free test?

Alternately you can buy one and if it doesn't fix the problem keep it for a spare.

Before you go ripping into the guts of the AC.......

 

[jrbrein]

I seem to remember that I had to disconnect (unscrew) all the breakers in that row in order to replace just one. When I realized this I ran out and purchased all my other A/C breakers to replace all of them rather than do this again. They were always the ones that tripped most often and so probably wore out soonest.

Jim,

Did you get your A/C breakers from Sam's?

Jon

 

[Bob Bradley]

Well, I went down with an electrician buddy Saturday to do some fishing and check it out professionally. Of course you can guess the result. The problem would not manifest itself with an electrician on the boat. It worked just fine.

Until the next time I need it.

 

[rustybucket]

I'd lean toward the reversing valve too. Unless the system is different than my splits the only real difference between heat and cool is the actuation of the reversing valve. There may be a 'slight' load increase on the compressor but it really won't be much, especially at startup.

You can easily disconnect the reversing valve by looking at the wiring diagram and pulling one of the leads off the start relay (usually where it is plugged into).

The reversing valve is just a solenoid, so can fairly easily fail. I believe you can replace the solenoid without replacing the entire valve. Although if the valve itself is stuck it would need to be replaced.

If you unplug the reversing valve and it still trips I'd turn to improper wiring, start relay and capacitors in that order.

While it could indeed be the breaker, I'd expect it to have the same behavior in heat AND cool modes. If it's not tripping in cool, I highly doubt it's the breaker.

 

[Fanfare]

I did not buy my circuit breakers from SAMS.

The original Hatteras 50MY electrical panel had about 20 circuit breakers, total, for the 110, 220 and 12 volt circuits. One breaker labeled "Port/Starboard Lights" covered all the 110v circuits on board. Originally there was only a single duplex socket in each room. In 1966 there was a real problem finding docks or marinas with adequate power. 220v was rare. Often we would use a two prong adapter (not even three!) limiting us to about 1,700 watts unless we ran the generator. We had three shoreline power cords, one 110v ship service, another 110v for the AC, a third 220v for just the stove. All three had the identical plug configuration. I was fortunate that the one time I mixed these up only one light bulb was on when I put 220v into the ship's service. Melted the filament right through the glass bulb!

All the duplex plugs on board had three prong faceplates. Only much later did I learn that these grounding (green wire) prongs were not connected to anything! Only the one on the front of the stove was. I was lucky not to have been electrocuted while using my drill in the bilge!

So some years ago I had a marine electrician make me a new electrical panel to go along with my simplified one-line 50 amp 220v shoreline setup. AC was no longer remarkable, so we split this across two legs of the 110v system. We separated many other circuits to reduce tripping breakers and balance loads. I am not on board, but I bet we now have 40 or 50 breakers. These are different from the original Hatteras ones, and that's why I did not get them from SAMS.

I had been using these replacement breakers as switches for each AC after changing from generator to shore power. This eliminated the surge load from all coming on at once which often tripped the master or shore breakers. Apparently this was another of my bad ideas so I don't do this any more. I turn each unit on at its control.