Yes you can operate the heater on the ground with the EPU on. I did a few times at UND here when it was -30 degrees and wanted the cabin warm while i preflighted. Anyway all the EPU does is make the battery not providing the power to the main bus to the seminole since the EPU will take care of that. It does not affect the heater fuel pump and fuel line from the left fuel tank. The power from the EPU will allow you to start up the heater and provide heat from the janitrol or the other combustion heater that we have installed on our seminoles.Though be careful to not run it too long or else you might get a heater over heat and have to scrub the launch. hope this helps.
-Farva
-Farva
