Isolating Wood Furnace from Oil Furnace


New Member
Nov 7, 2018
This is the second season using my Englander Wood Furnace. I know that I have a backdraft problem and fitting a plenum damper just isn't going to happen because my AC coil is so big and its too tight in there. House has 2 zones and I am tied into each trunk off the Englander. I have a 24V transformer wired up that only energizes when the blowers on the Englander are running. Is it possible to use that to power a t-stat or relay that would send a 24v signal to the Oil furnace control board and close both zone dampers and also shut down the oil furnace? I have an older EWC control panel and old EWC power dampers. On the control board if I change the damper switch from open to closed, it always keep the last zone called open, no matter what.

For a test, I swapped the power open and power close wires at the EWC Control panel to manually close the zone dampers and had the wood furnace running. I can definitely tell a huge improvement in air flow at the vents. So now I need a way to have those EWC dampers close when the wood furnace is on, but also shut down power to the oil furnace if the wood blower is running. I set the oil t-stat in the house to 63, so if the stove is out or we are not home the oil kicks on.

I will not be doing this, but I need to make sure that something like this is even possible before I contact a local HVAC company.


Minister of Fire
Aug 21, 2013
NE Ohio
Definitely possible...shouldn't even be that difficult. Without spending too much time thinking about it, I would say wiring in a couple relays should do the trick...

Former Farmer

Feeling the Heat
Apr 12, 2008
NE Wisconsin
If the oil furnace is not calling for heat, are the zone dampers closed?