Community Forums

rbates1944 · 01-02-2021, 05:27 PM

Is it possible to run the furnace fan without running the furnace?
In the winter we usually run two electric heaters, but they won’t keep the water lines from freezing, so I need a way to circulate the air. thanks

chuckftboy · 01-02-2021, 07:42 PM

It is possible with the addition of a fan relay and a switch to turn it on and off. It will require a little knowledge of 12 volt wiring and control.

waroland · 01-02-2021, 07:58 PM

My thermostat mode can be switched to fan only. I don’t know which t-stat you have, mine is a RV Comfort.ZC for Coleman Mach.

Outbound · 01-02-2021, 09:58 PM

I also have fan only on my stat, you may be able to change stats if you do not have fan control.

US1 · 01-02-2021, 10:22 PM

Mine also has a fan only setting, but it turns on the AC blower, not the furnace blower

Old-Biscuit · 01-02-2021, 10:40 PM

Quote:

Originally Posted by waroland

My thermostat mode can be switched to fan only. I don’t know which t-stat you have, mine is a RV Comfort.ZC for Coleman Mach.

Quote:

Originally Posted by Outbound

I also have fan only on my stat, you may be able to change stats if you do not have fan control.

Quote:

Originally Posted by US1

Mine also has a fan only setting, but it turns on the AC blower, not the furnace blower

Exactly^^^^^

The FAN Mode on thermostats is for the A/C Unit Fan

Furnace controls are via the furnace circuit board
Fan can NOT be run by it's self W/O modifications to wiring to Fan Motor

hohenwald48 · 01-03-2021, 07:17 AM

I added a switch to the furnace fan to operate it without the burner just for the reason described by the OP. It does take some electrical knowledge and the ability to understand the furnace schematic.

jacwjames · 01-03-2021, 07:37 AM

The furnace fan is loud and it would blow air throughout the RV with only a limited amount going to the basement. You might consider using a smaller type fan pushing air through the duct going to the basement.

When I had to winter camp and didn't want to rely on my propane furnace I securely mounted a small cube heater in the basement and used one of these https://www.lowes.com/pd/EasyHeat-Fr...roller/1060249
I plugged into the outlet used for a TV, which was off to the side and set the heater to high so the Easy Heat plug would control the temp On @ 39F and Off @ 54F.

I also put a remote temp sensor in the basement to monitor the temps with the display in the LR. Worked great.

David 70 · 01-03-2021, 09:45 AM

I know on my 2000 Adventurer the intake air for the propane furnace is in the floor under the pull out table behind the passenger seat. It pulls the air through the basement and then out the heat run. The coach heater from the engine heat also works this way. I would be leery of running the furnace fan extended periods of time.

rbates1944 · 01-03-2021, 10:21 AM

Thanks all for your help. Looks like i will have to pull the furnace to get to the wiring and install a relay.

153stars · 01-03-2021, 10:31 AM

Be aware the way the furnace works with induction air fan from outside you may get a decent amount cooling effect through the furnace. Efficient small fans may be better choice.

Old-Biscuit · 01-03-2021, 10:43 AM

Quote:

Originally Posted by 153stars

Be aware the way the furnace works with induction air fan from outside you may get a decent amount cooling effect through the furnace. Efficient small fans may be better choice.

Exactly ^^^^

Furnace Fan Motor is DUAL purpose...just like the A/C Fan
One side has combustion air wheel
Other side has room air wheel

Fan running will move room air thru registers/return back to furnace
BUT fan will also move air thru intake/exhaust
**Cold temps then cold air will be pulled into intake....thru heater exchanger and back out the exhaust
Room air will flow around heat exchanger and be cooled down from the cold outside air flow

Round Robin situation and inside of RV will get cooler and NOT distribute warm air

Cold weather/temps...run the Furnace so lines do not freeze

Which Brand/Model is your furnace??

Check out the 'Cheap Heat' add on.....electric heater installed with controller on furnace discharge
**Don't have any personal experience with it
https://www.rvcomfortsystems.com/add-on-system

saddlesore · 01-03-2021, 11:26 AM

Quote:

Originally Posted by old-biscuit

exactly ^^^^

cold weather/temps...run the furnace so lines do not freeze

I concur

Dutch Star Don · 01-03-2021, 02:34 PM

Just a thought.....I don't know your bathroom layout, but I'm guessing that that it sits over the tanks. If you have a raised toilet base or lower cabinet with room, think about installing a computer fan or inline duct fan into the floor of the cabinet or toilet base, that can pull warm air out of the bathroom and blow it down into the tank bays.