here is a problem I saw posted on another site... think the guy did some major damage... what do you think..??

""Oops!!. Can Someone help me!!
I have a Miller 225G welder/generator I have been using the generator lately to heat up a hot water tank which comes from the 220 on the generator to a 240v heating element just exactly like what is in your hot water heater! Being how I don't have a thermostat after about an hour when it is heated up plenty I shut the welder down unplug the cord and plug in another cord hooked to the same heating element into my 120v wall outlet to just maintain temperature!! So here is the oops!! The one time I forgot to unplug the 220v cord from the welder so it was charged from the 120v from the wall!! Now it barely turns over and builds what I would explain it as back pressure al
almost like the Onan motor itself is turning backwards!!
Please Help!!!! ""