apu question

it should start when its low to recharge the batteries.
i just had to jump mine to start, battieres were too low to start, its humming along now

 

It's possible the alternator on your apu might be done for, thus shutting itself off so it doesn't completely drain your truck batteries and you can start your truck.

 

That or the belt is slipping....one of the two.
Mine has done the same thing before,run a bit and shut off...reading low voltage.
It was the belt.

 

Carrier APU should only start and stop if you tell it to by setting it in COMFORT MODE or TEMP START MODE or BATTERY MONITOR MODE. It shouldn't kill itself if the truck batteries get low. The opposite. If in BATTERY MONITOR mode, it should START to recharge the batteries. It's part of Carrier's "Limp Home" feature that lets you turn on the APU to run the truck's electricals if the truck's alternator fails and the batteries get too weak to keep your engine running.

I'll give Carrier this: you can set the bunk control to make it sing, dance and whistle a tune. I'll knock 'em on; if you set the controls wrong (which is SUPER easy to do), it will come ON when you don't want it to and shut OFF when you don't want it to. Three different modes and settings within each of those modes and Sheeze!! TK beat the $#!+ outta Carrier with simple controls: BUT you can't use a TK to take the place of your truck's alternator and batteries if they go tits up.

If it was me and my Darla; I'd get to a Carrier place and let THEM look at what's going on.

 

Take a voltmeter and check the voltage at the nut on the back of the alternator. If that checks out at 13.6 - 15v, it's either in your wiring, or something in the CECU is going haywire.

 

You shouldn't be losing prime in the APU fuel system in that time.