Okay. So either it’s pulling too many amps…or there’s a problem at the electrical source (i.e., the outlet, the breaker, etc.)
Did you test the unit with an amp clamp and compare the reading to rated wattage? Here are the basic formulas to determine what the amp draw should be:
If the amp draw is good, then there’s a problem with the source. If so, call a licensed electrician. Equipment technicians aren’t usually authorized to deal with a building’s electrical issues.
If the amp draw ISN’T good, then there’s a problem with the unit. A schematic might help. However, the model you provided proves useless beyond the C5 part.
Anyway, with a good model # and some known operating parameters derived from that, a schematic can be used along with a DMM to troubleshoot it.
Here’s an example of a schematic.
This may not be the correct one since most of their manuals include four or five of them as they’re relevant to a specific unit’s incoming voltage, wattage…and geographical market. So, you’re better off using the one in the unit.
If all this is a bit much for you, then call an authorized service provider for the equipment. Here’s a link that will guide you there: