Wood furnace barometric damper issues and thoughts

So in my last post I mentioned needing a barometric damper and having some issues. This post will go through those issues experienced with the Vogelzang barometric damper sold at menards but it looks EXACTLY like this US Stove barometric damper on Amazon. It is so bad I’d be embarassed to sell the product or make the product.

But, before I get into that; if you have a wood furnace (not a stove, but a furnace that can use a digital thermostat) you likely need a barometric damper to prevent an over-fire condition. Stoves have a spring controller that will shut the damper automatically as it heats up and it can shut it enough to be safe. Another thing to make note of is that the barometric damper needs to be installed level, both the pins need to be horizontally level, but the face of it needs to be vertically level! The vertical thing is either not mentioned or easily missed in many places talking about barometric dampers. I made the mistake on my first attempt and it can cause issues (either damper won’t close all the way or it will be harder for it to open), though I’m pretty confident it had nothing to do with the issues I was actually experiencing.

So here are the issues with this cheap damper. The hinge is made of small pins that are captured in sheet metal so if there is ANY grime build up (dirt, dust, or smoke/creosote) the pins bind up and the damper can either stick open (causing no draft which ultimately leads to your house being filled with smoke) or stuck close (which is the same as not having the damper causing over-firing of the furnace). I first experienced this on a windy day when there were gust of wind that would suck the damper open and it’d stick and then puff back smoke into the basement. As the hinge gunked up from smoke it basically stopped working entirely (if you bumped it it would swing, but not easily like it needs to to work properly). Now, the smoke/creosote buildup maybe shouldn’t have happened, but with the poor design I’m pretty sure these issues are going to happen regardless. One thing I was unaware of, there is quite a bit of moisture in the firebricks int he wood stove. So, that coupled with the outside of my wood being damp from the rain, my first couple fires did have some creosote buildup. Actually, a better description is just moist smoke; so bad it actually condensed and ran from the joints in the stove pipe leaking what looked and smelled like liquid smoke all over. After 3 or 4 burns I stopped getting that. So maybe a couple good burns BEFORE installing the barometric damper would help not gunk it all up. However, I have a better one installed now that I don’t think the small amount of contamination would affect in near the same way.

Another poor feature of the big box store damper is that the swinging part looks to be stamped from the rest resulting in tight clearances. Good for not sucking out your conditioned air, but since the rest is so poorly built it can slide sideways and bind up. A bit more space would possibly prevent it from getting hung up like that (or a protruding spot that would positively keep it from getting to flush or past on the housing). Other than the poor construction and poor design its a partially useful item :-\

So, the better barometric damper? This Field Controls 6RC is SO much better of a damper! The hinge pin is larger in diameter, plus it is not captured on BOTH ends with sheet metal, only on the damper side. On the housing side it rides in slots on the edge of sheet metal so it is very low friction. Its also a fairly well calibrated unit (though I did get this one installed plumb and .06″ on the damper is more like .07-.08″, but its pretty darn close!) that a sliding weight can be moved to the amount of draft you need. I would skip the junk from the store and go straight to this one. It is two pieces, the curved piece meant for cutting chimney pipe on oil burners and the damper itself. I did not use the curved piece, I just slid the damper part into the T of the old barometric damper. I think you could use a normal T and slide it in there. In the instruction manual it says you can secure it with screws so long as they aren’t where they’d interfere with swinging gate.

So where do you get one of these dampers? Well, online (preferably at my Amazon link above so I get the small commission for the affiliate link) is pretty much your choice. I called a couple different stove / fireplace stores in the area hoping to find a good one locally and the people I talked to said I was on a snipe hunt trying to find one locally. He had sold ONE in the last 15 years. He asked why I wanted one and I mentioned my need on the wood furnace, then it clicked with him that yes, I probably did need one. They are not needed for stoves as mentioned above and wood furnaces must still not be that popular that people are likely to be looking for them locally. You could have your local fireplace store order one, but if you are installing (or even paying somebody to install) your wood furnace just go ahead and order it ahead of time online to make sure you get a quality one and not whatever you happen to find (IF you can find one at all) since its likely to be the garbage I showed above.

I have had the new damper installed for a day now. With the damper dialed in to maintain .07″ of draft I am now COMPLETELY confident that things are operating 100% properly. I fired up a lot of split wood to try to over-fire and the damper just swung open super easily and maintained the draft at .07″ where I had it set. The old one would have been up to .11″ or more after about 10 minutes unless I bumped it open manually. I closed the air intake and the barometric damper shut itself as soon as the fire died down just a bit. I swung it manually to the extremes and it does not feel like it can possibly get stuck open or closed. So I now will have confidence to let my wife put wood in the stove and crank the timer to let it fire for awhile if she gets cold. It is highly unlikely it will do anything other than operate properly.

On an unrelated note, one safety thing I did was hook a hose and sprayer up to the faucet that is in my basement (its already right there and on the main water stack) so if a spark does anything (for instance while I crack the door to get it blazing first thing) I can easily turn the water on and be able to quickly drench anything flammable in the area. Its pretty much an unlimited class A fire extinguisher.

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