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humboldt 03-04-2010 07:37 PM

help with forced air wood add on wiring?
So after 10 years of needing a new furnace, I finally took the dive and put one in.
I have a LP gas furnace, with a forced air wood add on that sits right beside it.
Well I got the furnace up and running, but when the wood add-on heats up the plenum on the gas furnace, the lp gas furnace fan motor doesn't kick on like my old furnace always did. Is there a jumper I need to install?
I am sure I need to give you more info, but if you can help, please do.

yuri 03-04-2010 07:45 PM

The new furnace has its fan turned on by a timer on the circuit board when the burner starts. The old one probably had a heat actuated fan control. Doubt if you can accomplish what you want easily. You can turn the fan to ON at the tstat if you have A/C and a fan Auto/On switch. If not you can rig up a switch on the side of the furnace between R and G terminals to manually turn the fan On.

beenthere 03-04-2010 08:10 PM

If your furnace doesn't have A/C.
You can install a fan limit switch in the furnace plenum. And just connect the ran side to R and G. it will then run the fan.

If you have A/C on the new furnace. That method won't work real well. As it will also back feed the stat and run the A/C on most thermostats.

yuri 03-04-2010 08:24 PM

Swipe the old fan/limit switch from the old furnace and use it.:thumbsup:
As Beenthere said, don't use this method if you have A/C or damage can occur.

humboldt 03-05-2010 07:20 AM

wow you guys answer fast.
I still have the old furnace, I will look for the old switch.
It did have ac, but the new furnace does not.
thanks a million!

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