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TXredfish · 05-01-2011, 08:42 PM

I am a little confused about how my 2 A/C work especially on 30A. My motorhome has 2 air conditioners, each one is 13,500 BTU - Dometic which uses a Duotherm control to control 2 zones.

Normally, to run both A/C, I would need a 50A circuit. But my home only has a 30A circuit and sometimes I have encountered campgrounds with only a 30A hookup. When at a 30A hookup, I have a converter plug from 50A plug to 30A plug. When I have a 30A hookup, can I control which A/C works by using the Duotherm control by setting zone1 (front A/C) - mode to cool and set temperature and the other zone2 (rear A/C), mode to off. And vice-versa to run just the rear A/C? Or because of only having a 30A plug-in will the A/C take turns if both zones are set to cool or will just one A/C run? Can someone explain how the A/C would work on 30A? I also have an additional problem. Sometimes the 30A breaker at the power pole will go off. I have a 20A breaker for each A/C built into MH. I could be wrong but I don't think both A/C could run at the same time on the 30A pole.
Thanks for your help............

Norm4015 · 05-01-2011, 10:12 PM

Your air conditioners work on 30-amp the same as they do on 50-amp. I have owned 50-amp Newmar motorhomes since 1999 and I often run both air conditioners on 30-amp. I just make sure the water heater is not on electric and the refrigerator is on LP. I also don't start up a big load like the microwave or washer and dryer.

You can run either the front or rear air conditioner while the other one is turned off at the Duotherm control panel. The air conditioners do not switch back and forth (front to back or back to front) while on either 30 or 50-amp.

GaryKD · 05-02-2011, 05:41 AM

Hi TXredfish,
There is no EMS (Energy Management System) in your coach. The process described in your OP is the correct way to operate your coach on 30 AMP service. The process you described is how I operate my coach. Run one A/C at a time on 30 AMP service. I have not had any luck operating two A/C units when on 30 AMP service. I have melted a power adapter trying to do this.

"007" · 05-02-2011, 07:36 AM

You can run both but be aware of having a problem if you add other appliances while they are on as Norm implied.
Something you may want to check are all screw connections in Transfer Switch and your load center for loose connections which will cause high resistance and cause wiring to over heat.