# Energymate Wood Furnace



## CMichael (Feb 25, 2015)

Hi All!  

I am new to this site and have enjoyed reading a lot of your posts.  I cant seem to find a thread to solve my wood furnace woes.  I know everyone has a different set up when it comes to wood furnaces.  I have an energy mate wood furnace that is connected to my LP gas furnace.  It was here when I bought the house 3 years ago.  I have a well insulated brick ranch of 1800 sf with a full basement.  Guessing stove is late 70's early 80's.  The stove runs great.  I have a stack temp between 300-500.  My thermostatic control on the stove reads 150-200 when there is a fire.  The blower fan in the back of the stove sucks cold air from my returns in the house, pushes air around the belly of the stove and it moves out the top and is vented above my furnace plenum into my duct work.  I have dry wood and can get a raging hot fire and keep a bed of hot coals for hours. 

I cannot seem to get my house above 70 on a cold day and cannot use my furnace fan to help push the wood heat through out the house.  I do not have a heat exchanger in my plenum.  I am wondering if I need a bigger blower fan behind my wood stove or if there is a damper in my duct work that closes when the furnace fan runs.  There is a relay attached to the cold air returns that runs to the blower fan.  There is a connection for red/white wires but nothing is hooked up. 

I bought the home as an estate so no one was able to give instructions on the set up they were using.  Any help would be greatly appreciated.  I LOVE wood heat but I am getting frustrated with the lack of heat in the living space.  Thanks so much for any help!


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## begreen (Feb 25, 2015)

It could be sucking in a loop. Is there a back draft damper installed in the gas furnace plenum to prevent this?


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## brant2000 (Feb 25, 2015)

begreen said:


> It could be sucking in a loop. Is there a back draft damper installed in the gas furnace plenum to prevent this?



Exactly what I was thinking.  I just found this picture to help illustrate how it should be installed.




You could probably wire that relay to operate your furnace fan in parallel, but if the static pressure of the furnace fan overwhelms the pressure produced by the wood furnace fan, you'll get reverse or no flow through it.


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## JRHAWK9 (Feb 25, 2015)

Are you sure the house is insulated well enough and keeping enough heat inside in order for it to be physically capable of keeping the house at 70°?  Heat loss is exponential.  BTU's required to heat the house to 70° when it's -15° outside is MUCH more than it is when it's +10° when the house is poorly insulated.


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## brenndatomu (Feb 25, 2015)

Two things I see
1. The pipe feeding cold air to the wood furnace blower is too small. It shoud be upsized right at the blower clear back to the return duct. Shorten and straighten the run if possible too. Or at least use (2) 45s instead of (1) 90 on the corners, smooth out the airflow
2. To test if the main furnace is backflowing, slide a piece of tin or cardboard in the filter slot. This will block the "loop" so you can see how much it helps. Don't run the main furnace with the filter blocked! Install permanent dampers if this test helps.


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## laynes69 (Feb 25, 2015)

If your running your exhaust that high (external or internal?) and your limit control is reading between 150 and 200 (if I'm reading right), you should have more than enough heat for the home. Judging by the burnt paint on the cabinet, the previous owners had the same problem. If it's not backfeeding into a loop as suggested above, then I would be under the impression your home isn't as tight as it should be. It's also been a very cold winter (we had -18°F temps the other morning). We kept the house about 70°, but our woodfurnace got a workout.


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## DoubleB (Feb 25, 2015)

My eyes might be tricking me, but in your first picture it looks like your round duct has a damper, and it looks like that damper is mostly closed.  

Hate to ask the obvious, but how does it work with the damper open?


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## brenndatomu (Feb 25, 2015)

DoubleB said:


> My eyes might be tricking me, but in your first picture it looks like your round duct has a damper, and it looks like that damper is mostly closed.


Oh wow, you're right, good eye!


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## DoubleB (Feb 25, 2015)

Or maybe just lucky...


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## CMichael (Feb 25, 2015)

begreen said:


> It could be sucking in a loop. Is there a back draft damper installed in the gas furnace plenum to prevent this?



Im going to check that on Sunday when the temp heats up outside.  I had pondered that thought as well.  There is a backdraft damper on the stove itself (currently wide open).  It was a little warmer today (20 degrees) and I have tried for the first time just letting the furnace fan run with a good fire in the box and for the first time letting my draft blower wide open.  The house has warmed to 70 but the radiant heat through out the house feels amazing.  Waiting for colder temps tonight to see if that disappears.


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## CMichael (Feb 25, 2015)

brant2000 said:


> Exactly what I was thinking.  I just found this picture to help illustrate how it should be installed.
> View attachment 154569
> 
> You could probably wire that relay to operate your furnace fan in parallel, but if the static pressure of the furnace fan overwhelms the pressure produced by the wood furnace fan, you'll get reverse or no flow through it.



I have read on here that is how some cool their home down.  When the fire rages, the upstairs thermostat kicks the furnace fan to circulate and regulate the temp.  I also thought of running the draft blower to a second first floor thermostat so when the temp gets too high, it would shut the draft blower off thus slowing the burn.  Is that even an option with the Energy Mate or does that create a slower fire that allows creosote build up?


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## CMichael (Feb 25, 2015)

JRHAWK9 said:


> Are you sure the house is insulated well enough and keeping enough heat inside in order for it to be physically capable of keeping the house at 70°?  Heat loss is exponential.  BTU's required to heat the house to 70° when it's -15° outside is MUCH more than it is when it's +10° when the house is poorly insulated.



My house was built in 1976.  1 story brick ranch with plaster walls.  Has original Andersen windows.  They could use replaced.  Put 15'' of blown-in in the attic 3 years ago.


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## begreen (Feb 25, 2015)

CMichael said:


> Im going to check that on Sunday when the temp heats up outside.  I had pondered that thought as well.  There is a backdraft damper on the stove itself (currently wide open).  It was a little warmer today (20 degrees) and I have tried for the first time just letting the furnace fan run with a good fire in the box and for the first time letting my draft blower wide open.  The house has warmed to 70 but the radiant heat through out the house feels amazing.  Waiting for colder temps tonight to see if that disappears.


There needs to be a companion damper in the primary furnace plenum so that the supply air from the wood furnace is not sucked into its return air feed.


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## CMichael (Feb 25, 2015)

brenndatomu said:


> Two things I see
> 1. The pipe feeding cold air to the wood furnace blower is too small. It shoud be upsized right at the blower clear back to the return duct. Shorten and straighten the run if possible too. Or at least use (2) 45s instead of (1) 90 on the corners, smooth out the airflow
> 2. To test if the main furnace is backflowing, slide a piece of tin or cardboard in the filter slot. This will block the "loop" so you can see how much it helps. Don't run the main furnace with the filter blocked! Install permanent dampers if this test helps.


 
Great ideas!  Thanks so much!  I saw youre from NE Ohio.  Whereabouts?  Im in Columbiana.  Just 20 min south of Youngstown.


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## CMichael (Feb 25, 2015)

DoubleB said:


> My eyes might be tricking me, but in your first picture it looks like your round duct has a damper, and it looks like that damper is mostly closed.
> 
> Hate to ask the obvious, but how does it work with the damper open?



Yeah it looks that way but the indent on the srew that holds the damper in the duct is pointed north/south.  I also checked by taking the duct apart to see what was going on in there.  lol!  I will have to loosen the wing nut and readjust it.  Good eye though!


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## CMichael (Feb 25, 2015)

begreen said:


> There needs to be a companion damper in the primary furnace plenum so that the supply air from the wood furnace is not sucked into its return air feed.


Is the companion damper electronically or thermostatically controlled or is that manual?


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## begreen (Feb 25, 2015)

Normally it's spring or counter-weight loaded and opened by the air pressure behind it. But they do make motor operated versions too.


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