Dometic AC pulling 53 amps on start, fan runs, AC cycles

[Capttuck]

Dometic AC pulling 53 amps on start, fan runs, AC cycles but won’t stay on

Hello all. Getting ready for a trip and went to run my rear AC (Dometic 15K) in my 311BHS and I am having issues.
Camper is plugged into a 30 amp line at my house, 50 amp reduced to 30. I only run 1 AC at a time at home as I know the limits of the amps. On the rear, My surge guard will show 120 volts and 2-3 amps when I turn it on as the fan runs. As soon a the compressor kicks in, amps spike to 53, volts drop to 103, compressor stops and fan continues to run. A couple of seconds later, it will then try to restart and the same thing happens. I checked the capacitor and it tested good. I started my front AC (Dometic 13.5k) and it ran with no issues, 2-3 amps and then went to the 13 range when compressor was running.i leave in a week for Florida and I need to figure this out. Should I go to a local campground and plug my 50 amp in there and see what happens? Do I just buy a new one? Any advice or help would greatly be appreciated.

 

[Hoopy Frood]

At 53 amps, I would venture that the compressor has left the building. Especially when you compare it to the other one. With a 30 amp line, I would think you would kick a breaker somewhere. When my front AC went bad, my Watchdog shut down immediately when the amps hit over 60 when the compressor tried to start. FWIW, I've read, and been told, that the RV AC's are not rebuildable/fixable. If it quits, you buy a new one. Personally I think that's a bit of a waste.

 

[Second Chance]

I agree - sounds like the compressor is gone.

Rob

 

[poohbear]

How did you test the run capacitor ? If its weak or open 53 amps at start then overload opens is not unrealistic.
Double check the cap. In my hvac career I probably changed enouh capacitors to put one of our kids thru college. If it is the compressor, junk it . These 15k btu 110volt compressors are almost the cost of a new unit especially when you add in labor & refrigerant.

 

[Bobbybrown111]

your 30-amp setup can't handle the rear AC’s startup surge. Testing at a campground with a 50-amp connection is a good idea before buying a new unit. You might also consider installing a soft start kit to reduce startup amps. For detailed info you can contact https://alphamechanicals.com/service-area/citrus-heights-hvac-service HVAC services in Citrus Heights.

 

[Scott'n'Wendy]

Bobbybrown111, The OP posted the question back in July and never came back.

 

[triplethreat]

I realize that the OP has not been back since posting, but I do want to add this in, just so everyone knows.

When an induction motor, like the one that is part of the the A/C compressor, starts up, there is a large surge of inrush current at the motor. Technically it is called "locked rotor" current and that is because the instant the the voltage is applied to the motor, it is obviously not spinning or turning.....so in effect, that is the current that you would see if the motor was in fact locked up. A few milliseconds later (after power is applied), the motor starts spinning and as it is coming up to it's rated speed, the current dies down to the FLA or Full Load Amperage......12/13/14 amps.
So the bottom line is that when starting, the motor will be pulling approx. 4 TIMES it's normal run current. Fortunately, that transition from Locked rotor current to FLA is normally in the millisecond time frame