Okay, here's the deal. I'd like to set something up that will allow me to run my furnace for short (emergency) periods when the power is out. I tried an 1800w Coleman generator with no success. Some background: I have an Armstrong 90%+ efficient furnace with a "blue" smart valve. With the Coleman generator, the draft motor wouldn't even start. The voltage read over 130v going to the furnace. I figured it was either that or maybe the frequency was wrong. BTW, the blower would run just fine.
So now, I tried a Vector 1500w modified sine wave inverter, hoping that the voltage would be cleaner. The draft motor will run now. Blower runs, too. However, my so-called smart valve thinks it has an open limit, when I know for a fact that it doesn't. However, with a perceived open limit, it won't go through the ignition sequence... I tried putting the inverter under load, but still no success. No load voltage reads 91v, full-load (a 1500w heater) is 110v.
Is there anything I can do, such as an inline capacitor or something else, to clean things up so that my furnace will be willing to work with the inverter?