Front AC shed on 50 amp power

[Jrampey]

I am currently connected to a 50 amp pedestal - 117 - 121 volts on each leg- power supply appears to be good. Firefly indicates that the front AC is shed… rear AC is working fine and keeping everything cool for now, but…

2019 Forza 34T Coleman AirXcel 47000 series heat pump

When I select Cool on the Firefly control panel after a short delay the fan starts but no cool air, the display flashes between Cool and Shed. I can turn off the rear AC and try again- same thing. No major loads are on. Batteries are full.

I did a complete reset of power… removed the plug from the pedestal, powered off chassis and coach batteries- inverter off and back on. No change.

Any thoughts?

Joe

[creativepart]

What comes to mind for me is an issue with your front A/C unit. A bad compressor can spike the amps to very high levels. This seems especially possible if when you turn off the bedroom A/C the front A/C won’t run on compressor.

[Jrampey]

I guess a trip to the roof is needed. I have the necessary meters and tools to troubleshoot the electrical supply. I’m praying it is a capacitor…

With the firefly indicating the load was shed I wasn’t sure- but I guess a momentary surge trips the hi amp trigger in the firefly system.

[MakoMike]

Question: What does shed mean?

[Ray,IN]

Originally Posted by MakoMike

Question: What does shed mean?

Some RV's have a Power Management System. It detects the electric power source and automatically shuts off appliances based on total amps being consumed to prevent tripping the main breaker, it's called load shedding.


I agree with creativepart's reply.

[Jrampey]

Finally got on the roof with a good amp meter… amperage spikes and holds at 48 amps while the compressor tries to start… without success. It sounds like the compressor is locked! Voltage dips from 122 to 112 while trying to start. Bad compressor? Unit tries to start for about 4 sec then shuts down for 3-4 minutes then tries again.

Time for a new a/c? Any recommendations that will drop in and use the firefly controls?

[creativepart]

Likely you got a leak in a refrigerant line and lost all the refrigerant, losing the oil in the process. This leads to a failed compressor. Fairly common issue. Especially if yourA/C is out of warranty (>2-yrs old).

[Morich]

But, before changing the expensive part, are you up on how to test the capacitors?

Possible to avoid the big bullet if it is a totally bad capacitor. Maybe just a quick look with a meter or even looking at the tops. They are oftendesigned with a weak spot cut into the ends to split in a direction which lets them spill out in a better direction and not all over the other parts. That can make spotting a bad one lots easier.
If you find one with a bulged end cap, look at changing that before the compressor?