2 wire thermostat replacement, "fan only" possible?

[Komrade]

My (new to me) BigFoot 2007 17.5 has at Atwood themostat.
I googled replacing it, and found many solutions.
Do 2 wires allow for fan only option?

Fan only could be useful if you wanted to use electric heat and still rotate air to the tanks whenever cold.

[tractors1]

Nope. Furnace isn't wired for that. You could add a separate switch and 12V line to the fan itself. Did that for a truck slide-in where the tanks were below the floor to keep tanks from freezing while skiing.

[Komrade]

OK, thanks.. that's what I suspected.. Can't do too much with a mechanical spring and 2 wires other than close a contact.

[Adirondack Anthony]

I'd opt for a small electric heater with its own fan. However, if you shut off the propane at the tanks and set the thermostat to above the inside temp, then the furnace fan will kick on, just no heat. At least that's the case with my Casita. Be sure the fridge is set to AC.

[Terry in Fowler]

Be careful. Circuit boards are easily damaged by current in the wrong place and they're expensive. It can be done but depending on the purpose it is probably best buy a cheap 12v fan. If you're trying to keep the fan from turning on and off all night long it will use a lot of power in the process.

[WaltP]

It sounds like your main interest may be having the fan work for circulation when you have a separate electric heater on. One solution might be installing a maxxfan in the ceiling. Unlike the Fantastic fan the Maxxfan has a ceiling fan mode just for that purpose. You can run the fan with the cover closed.

Walt

[CharlesinGA]

The OP is wanting to use the fan on the furnace because it supplies the waste and water tanks with heat to prevent freezing. I was just pondering this very thing the other day. Heat the inside with a space heater and use the furnace to push the warmth down below. What would be nice would be a furnace that has a 1200 or so watt heat element in it so you have heat without dealing with a space heater.

Charles

[Komrade]

FYI, I did replace the themostatat (no fan only option).
Emerson/White Rogers 1e78-140

The fan does appear to kick in with propane off, but I didn't experiment how long the furnace will keep trying to fire itself up, and if it will ever give up, and figured it can't be good for the furnace either way (easier to replace a $20 heater)

I have ordered a 200W Lasko heater on amazon, which I will pair with ThermoCube outlet type thermostat that kicks in at 35F and stops at 45F. I will place both it in "wet bay" for now with an extension cord ran through one of the cabinets, but I should be able to add a 110V outlet there at a later point. Will also "secure" Lasko via a Velcro so I wouldn't have to pull it if I am moving the trailer.

Will also monitor temp from home via remote thermometer such as ThermoPro TP63B

Inspired by this post
https://www.irv2.com/forums/f258/bay...rs-149096.html

[WaltP]

Sounds good. I have used a Thermocube for several years. It seems to work well and provides some peace of mind.

Walt