2008 KA 5th Heat Pump issue

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The heat pump on my 2008 Kountry Aire fifth wheel has operated flawlessly until now. It is the original factory unit. The past week or so it has been tripping the breaker, most often on heat pump mode. A clamp on meter shows normal draw on start up and then slowly rises until it reaches over 20 amps at which point the breaker trips. On cooling mode the rise in draw is slower and sometimes stabilizes without tripping the breaker. Yesterday however while I was out, the cooling mode tripped the breaker. It was 85F out. I restarted the unit and it did not trip the breaker again. To add to the saga, I retrieved a small piece of flat rubbery material wrapped in aluminum duct tape from on of the outlet ducts just ahead of the unit location. It looked torn. Air flow out of all the outlet ducts seems normal and I seem to get good cold and heat out of the ducts when the unit is running.

Amp draw is normal in both modes initially. In heat mode it can take anywhere from 20 minutes to an hour for the breaker to trip. The fan motor draw is and stays normal when on “fan” mode. The motor spins freely and there is no side or end play. I have cleaned both coils although neither appeared dirty. Start and run capacitors test good; well within specs.

I am suspecting improper air flow in the plenum where return air is mixing with the heated or cooled air. Raising pressures in the compressor. I have ordered a good quality replacement roof gasket as I don’t want to remove the unit without a new gasket in hand.

I have tried to find a diagram or photo of the plenum in these units but so far no luck. I think that Newmar was doing something unique in the way the duct work was attached to the plenum. I assume the piece of material (L shaped and about 1.5 inches high by a couple inches long) is part of the puzzle.

Since Newmar used this system on most of their units back then I am hoping someone may have had a similar issue and solved it or has a photo of the plenum. One of the folks in the park here is a heating and cooling contractor agrees is and air flow issue based on my testing.

Any help or suggestions appreciated.

Casey