Furnace without propane

[Ladiver]

I saw a post here the other day about someone setting up a bypass switch to allow the furnace fan to run without using propane. They set a space heater next to the intake and allowed that to be the heat source.

Anyone remember that post and who did it? I have looked all over and could not find it.

Thanks,

Jeff

 

[TandT]

Jeff,
THIS might be it. Trace

 

[Ladiver]

Not quite, though it sounds like the OP in that thread may be talking about the same concept that I saw.
The post was talking about a modification that installed a switch allowing the furnace fan to run without firing on the propane heat. Flip the switch one way and it is basically a fan using an electric space heater at the intake to heat. Flip it the other way and it uses the propane to heat.

 

[Speedy]

The "Fan" setting on your thermostat should accomplish your request.

 

[danemayer]

The "Fan" setting on your thermostat should accomplish your request.

Fan setting on the thermostat set to HI or LOW will cause the A/C unit's fan to run. Doesn't affect the furnace fan.

 

[HornedToad]

I remember that post with a hand drawn diagram.

I thought it was a great idea... "Flip the switch one way and it is basically a fan using an electric space heater at the intake to heat"

but this quote on a post from our friend Good Sam doesn't!!!

"Rigging the furnace fan could be done, basically would need to add a 12V SPDT (Single Pole Double Throw) relay in between the fan motor and the control board. The relay basically selects between the control board or direct 12V to the fan motor. Then a simple toggle switch can be used to turn the relay on for bypass.

HOWEVER running the fan by it's self is going to waste your heat. The reason for this is the furnace fan motor does double duty, it not only blows the inside air across the heat exchanger, it ALSO drives a fan on the burner chamber. This means the burner chamber is going to have COLD, COLD outside air being drawn into the burner chamber and PUSHED through the BURNER SIDE of the heat exchanger.

This will CHILL the heat exchanger and the inside air drawn across it will be cooled. Added to this you will be drawing warmer inside air (which in a RV is very humid) and condensing the moisture on the cold heat exchanger. This is going to cause a lot of rust to form on the heat exchanger.

Honestly, I really don't understand why folks who camp in the winter seem to be extremely cheap. SPEND the money on propane and use your furnace the way it was designed..."

I was going to leave that last part out, because I'm one of the "extremely cheap" folks who thought it was a great idea.

 

[Ladiver]

Thanks Mike,

That was the post. I had not paid too much attention to it, I figured I would go back and read it. Thank you for the second quote. I knew it sounded too perfect. I will not worry about the propane.

I will use space heaters and the fan during the day and run the furnace at night. I don't worry too much about propane because here in socal, we only run the heater a few times!

It looks like we chose to camp on the coldest weekend of the year here! Thank goodness we are headed south to San Diego. It will be a little warmer there than at our home. It also looks like we may get SNOW! at our house. The low is high 20's and there is a 70% chance of rain on Sat. If the storm is stalled by several hours, I don't think it can rain at 28 degrees. It could either be a beautiful white or a nasty clear. It would be fun, but I don't think I will miss it. I spent 4 years near Fargo, ND. I saw plenty of white stuff.

 

[ParkIt]

The Vornado fans take up little space but disperse evenly and quietly, I've got 2 small ones mounted at the bottom of the bookcase/storage over the couch in the back plugged into the outlet at the bottom. Using those I can direct the heat from the fireplace heater anywhere, its worked out better than the ceiling fan which seems to just blow it into the upstairs bath and bedroom.