Furnace not fuctioning.

[wallooner]

I have a 1977 Sovereign with the original furnace which does not work. I first want to check to see if it is getting power. Does it have it own fuse on the low voltage panel or somewhere else? I have the original manual but no fuse is specified for the furnace.

[dbj216]

The furnace will not have its own fuse. It is likely on the same circuit as other 12v items. There are 12v fuses and circuit breakers in your fuse box.

Test to make sure all 12v items work in your trailer; lights, fans, water pump, etc. If so, then it's not likely a fuse. Usually there are 4 wires to your furnace. Two are power, and two are thermostat. The power wires are larger in diameter (gage). Your wiring diagram may tell you what color the ground wires are. In my 66, they are white. Check your ground wire from the furnace and insure it is in fact a good ground. It should test at 1 ohm or less. Then check for 12v delivered to the furnace. That ought to be 12.5 volts or higher.

I might add the thermostats in these old Airstreams can cause the furnace not to run. Make sure your thermostat does function. You can "jumper" the two thermostat wires together and your furnace is commanded to run. If it doesn't, then you are back to the 12v power to it.

It is likely to take some dissassembly of cabinets, etc, to get reasonable access to your furnace. Please turn off your propane while working on the furnace. Once you get your fan motor to run, then you can worry about the pilot light and other furnace functions.

David

[perryg114]

My advice is to get a new furnace. One that old is not going to be reliable and may even be dangerous.

Perry

[PizzaChop]

Probably not what you want to hear but it might be advisable to consider replacement, regardless of whether or not you can get it to function. The heat exchangers tend to develop leaks over time (rust) and given its age, it's probably likely.

I've replaced two of them (72 Overlander, 73 Sovereign) and there's a real peace of mind knowing that that the furnace is safe to use when you go to sleep at night.

I started on the quest to repair but a replacement part could not be procured from Suburban, and when they learned the age of the unit, they strongly urged that I not use the furnace but replace it with a furnace that wasn't already 30 years old.

Others may disagree but I'm in the "better safe than sorry" camp when it comes to rv furnaces.