Comfort Pro Apu problems I can't figure out?

www.apucenter.com can answer your question.

 

It won't start your truck , but it(apu)should start and charge your batteries. I haven't had a Carrier apu in a long while. What you need to do is set the battery monitor so it will start the apu at the desiered point.
You should be able to find this setting in the display.
It will probably say voltage setting it will alow you to set the low point for the batteries like 12.5 or whatever.
If you can't find it in the settings type SETTING BATTERY MONITOR ON A CARRIER APU into the search box on your home page you'll get a bunch of results you can sift through.
Including a PDF download of the manual.

 

There is several things to look at

1. That you are not “locked out” of the key menu items with password protection
2. That the “Battery Monitor” function is On (should see a “battery” in the top of the display screen)
3. That the voltage threshold is set to where the APU will come on to charge BEFORE circuits start shutting off (like power for the fridge)
4. That the voltage calibration is properly set (in the APU)

Refer to a manual or stop into a Carrier dealer to get a manual and/or pointers

 

First calibrate your Apu. Take a reading of your batteries with a voltmeter, then input that number. Then go to your battery monitor setting and then adjust where youd like the Apu to kick on when the voltage drops to that point.