I have a Coleman Mach 3+ non ducted AC. Recently it started having an amperage spike after about an hour and trips a 20amp breaker on the house (I know I need a 30a) or it faults my generator which is a new Champion 3500w generator. It does not trip any breakers in the camper. It also never trips a breaker or faults the generator at start up. Just after an hour or slightly under is when the issue happens.

Yeah, 20 amp is really marginal. How do you know it is an amperage spike by the A/C? Could be your converter kicking on. Or water heater if it is on. Or??

Nothing else is running. Water heater is propane.

If you are plugged into the house, say the garage outlet, it might also run the bedrooms, or something else? The RV will have come loads run all the time, unless you shut them off. The converter will charge the battery. In my 97 Bounder, the converter would also trip the GFI. So you might be very close to or slightly over 20 amps going from the circuit breaker to whatever load it is connected to. What size wire are you using? #10 should be used, or plug the RV power cord directly into the wall receptacle. You might have a weak or bad compressor run capacitor, they are about $18 at Amazon, so worth replacing it if it is over 10 years old.

Roof top A/Cs are usually less than 15 amp draw.. No problem on a 20 amp breaker if they are running well and do not need a good cleanout of the condenser coils.WAIT. SUSPECT.. What happens if the condenser is dirty (And note on most A/C's the dirty side is the side you can not see.. AirExcell (Coleman) is the only Sucker I know of.. The rest blow.. By that I mean suck/blow air through the condenser.. Suckers get dirty on the OUTSIDE where you can see it)Normal operation.. An A/C is a heat pump.. it pumps heat from the Evaporator to the Condenser.. then a fan blows outside air over and through the condenser to carry the heat away.. Dirty Condenser: The air does not move freely and thus heat builds up. as the heat builds up.. Charles law comes into play (Dang I went to College about 1970 and I still remember it's Charles Law.. Scary).As The heat builds Charles law says the volume of the refrigerant increses.. And because of something called the Thermal Constant of Expansion... It increases faster than the volume of the tubing and passages so the pressure goes up up up.Now as the pressure goes up the compressor has to work harder and harder to push refrigerant through the lines... and the harder it works the more current it draws.Now since it's taking an hour... (It's not Really Really dirty) That would take only 15-20 minutes in my case) but I would suggest you go "Up on the roof" with the tools (#2 Phillips on most rigs) to clean the thing.You will likely have to remove the shroud (Around a dozen screws.. take a magnetic parts tray with you) and then an inner cover.. (Assorted ways they do that some are real easy (Like 6 screws easy) some are ... "Fun" (Not one bit). Coleman.. Take a bigger Screwdriver (like A #4) in addition to the #2.. 4 Bolts lift the shroud peal the condenser replace shroud and bolts.

When the breaker trips is there anything in the house that stops working at the same time? Common practice to wire multiple outlets and/or lights to each circuit breaker.

AC getting amperage spike after an hour use. | Good Sam Community

Golden_HVAC
Explorer
Jun 22, 2023
If you are plugged into the house, say the garage outlet, it might also run the bedrooms, or something else?

The RV will have come loads run all the time, unless you shut them off. The converter will charge the battery. In my 97 Bounder, the converter would also trip the GFI. So you might be very close to or slightly over 20 amps going from the circuit breaker to whatever load it is connected to.

What size wire are you using? #10 should be used, or plug the RV power cord directly into the wall receptacle.

You might have a weak or bad compressor run capacitor, they are about $18 at Amazon, so worth replacing it if it is over 10 years old.
ouliwei
Explorer
Jun 22, 2023
Nothing else is running. Water heater is propane.
BB_TX
Nomad
Jun 22, 2023
Yeah, 20 amp is really marginal. How do you know it is an amperage spike by the A/C? Could be your converter kicking on. Or water heater if it is on. Or??

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AC getting amperage spike after an hour use.

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