Furnace blown fuse - more than once.

[Bwuthrich]

2017 Whitehawk with a propane furnace and “basic” analog thermostat. Cause for blowing fuse?? Last two trips the 20 amp fuse blew (neither furnace or A/C will work). Replaced fuse and both would work. Travel to next location and fuse blows again while in transit. I have checked for loose and/or touching wires in the A/C unit, in the wall behind thermostat and at the breaker/fuse panel. Any thoughts as to what could be causing the fuse to blow? Recent development.

[CampinFred]

This is the AC 20 circuit breaker that tripped or was it a plastic fuse that gets replaced?

[Bwuthrich]

Originally Posted by CampinFred

This is the AC 20 circuit breaker that tripped or was it a plastic fuse that gets replaced?

Plastic “spade” fuse.

[CampinFred]

Does the fuse blow if you don't fire up the furnace but turn on the AC? The HVAC system is similar to a household, in that when you have a thermostat with some shared leads. The R wire gets power from the heat system, so if the power to the heat blows, that would explain the AC not working. Hopefully this helps a tiny bit by narrowing it down to the furnace. If you feel like getting your hands dirty (assuming no warranty) pull the furnace out and check that the fan isn't locked up. That's the most common cause for blowing fuses. Maybe it's something easy like debris jamming it up. The heat systems in trailers is a little archaic in that there's no filters and so it can just suck in anything floating around.

[CampinFred]

Here's a good video that shows how to tear down your furnace to replace the motor.

https://www.youtube.com/watch?v=kz9JEn9y6ZY

[Bwuthrich]

Originally Posted by CampinFred

Does the fuse blow if you don't fire up the furnace but turn on the AC? The HVAC system is similar to a household, in that when you have a thermostat with some shared leads. The R wire gets power from the heat system, so if the power to the heat blows, that would explain the AC not working. Hopefully this helps a tiny bit by narrowing it down to the furnace. If you feel like getting your hands dirty (assuming no warranty) pull the furnace out and check that the fan isn't locked up. That's the most common cause for blowing fuses. Maybe it's something easy like debris jamming it up. The heat systems in trailers is a little archaic in that there's no filters and so it can just suck in anything floating around.

The Heater and A/C both work fine - after replacing the fuse. The fuse blows when traveling. I have checked for loose wires and bad connections, and all looks good.

[Bwuthrich]

The Heater and A/C both work fine - after replacing the fuse. The fuse blows when traveling. I have checked for loose wires and bad connections, and all looks good.