Need advice on a Furnace Problem

[Retired Phil]

I'm not sure if I have a problem with the furnace or the thermostat on my MH? At times the furnace does not cut off when the set temperature is reached. We bought this MH last Spring and the temperature regulation seemed to be good while using the A/C units.

I keep the MH parked next to my house and it is plugged into a 120 volt outlet with a standard 15-20amp extension cord. Since the Winter in South Louisiana doesn't get very cold, I simply drained the water tanks and lines to winterize the unit. For the few nights that get below freezing, the furnace is turned on so that the MH is kept around 50F degrees. Sometimes the temperature in the MH has gotten to 90F degrees and the furnace is still running when I go to shut everything down in the morning.


Any advice on where I should start checking would be appreciated. This is the only time the furnace has been used. When we camp I always get at least 30amp electric service so we use the heat strip if heat is desired.

Thanks.