I have 2 MultiPlus 24/3000/70-50 120v set up as split phase at 180. I have 1 air-conditioned connected to each line. I have ran both AC units in the past. One of the Mulitplus just started to shut off in 15 to 30 minutes of run time It's Line 1. I can still run the AC unit on line 2 without any issues. I even switched what AC run on each line and its still shutting down. I have updated the firmware in all the devices. What should I be looking for. Do I have a bad MutiPlus