Wood burning furnace
 

Here is a picture of our wood burning furnace. Would someone please explain how to adjust the vents for a slow burn. Our fire isn't getting through the night. Sometimes burns down after a few hours. I'm sure it can be adjusted to make it last longer. Thanks.
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No, I'm not sure it can either.

I have a US Stove "Hotblast" furnace in my shop, and neighbor has one in his basement. They simply will not hold a fire all night, and we've both fiddled with them quite a bit.

One of you should just bring your furnace up here to me and I will run a series of tests on it for the next dozen or two years. I am sure I can get a nice long burn out of it and I will work on it daily until I do.:D

Please keep this updated. I am looking at these type of furnace

Yeah, I'll be up in the morning with it. You have the coffee and doughnuts ready....

Seriously, US Stove, based here in Tennessee, just makes real good looking junk stoves near as I can figure. Not impressed with them, would not buy another.

Fortunately, the one I use in my shop I really only use when I'm in there....the shop is built back into the ground and insulated well enough it never freezes in there. But my neighbor (he was over today and we were talking about his furnace) says the only way he can hold a fire is shut the air completely off, and then he basically gets no heat in his duct work (he tied his in....mine just blows out in the shop), or he can get a good fire going, get good heat, for about 3 hours.

It is really sort of basic. You need a firebox big enough to hold a good load of wood. Then you need a way to limit air intake. An air tight furnace should be able to crank everything shut and nearly put out the fire. If you have it completely turned down and it burns everything up in 4 or 5 hours, it isn't air tight and you cannot throttle down an air leaky furnace.

Without seeing it in person, and messing with it, I am not sure. But if you are in TN, it may not be getting cold enough, or your house is so well insulated that you dont ever need a big enough fire. You should be able to build a campfire out in the woods and still have coals left in the morning. Depends on how you "bank" your fire up.

I have a schrader wood stove, I keep fire in it all day, and for weeks at a time. Get a good bed of ash and coals. Are you cleaning out the firebox regularlly? Maybe that is the problem. I let my ashes get 4 or 5 inches deep. This insulates the coal.

Before I go to bed in the evening I put a big chunk of wood on both sides of the existing coals, then place three or four chunks tightly on top and around. Make a box around the existing ash and coals. But a tight fit, not leaving much open space if I can help it.

Then I shut the air down, leaving just a little trickle of air.

You have to get to know your stove. It also depends on the shape and size of he firebox. Is it lined with firebrick? If it is big, and depending on the size of your wood, push it back in the corner, away from the door. Pack it in tight around the existing coals, the shut the air back.


If your house if tight, or the weather warm, the house may be getting too warm with even a light fire.

Up north we dont have that issue.

Supposed to be like -6 or -8 Wed evening. I'll pile it full then.

Good luck, Gene

I keep the intakes in our door tightly closed, and control the air flow with the bottom wheel in the ash door. It took me a few years to learn that. I was told that the vents in the door are for coal, since coal burns hotter and needs more air. Anyhoo, try keeping the upper vents closed tight, and the bottom vent barely open. Please realize, though, that a continuous slow burn will build up creosote quicker in your chimney. Even if you use a good quality wood, you'll get a buildup and can increase your chance of a chimney fire if you don't clean it regularly. Curt

Thanks all. We have tried so any ways of adjusting vents and how we bud the fire. And still get about a 3-5 hour fire. Just thought I'd check and see if it was us. Sounds like probably not. It's what we have and it works and we are thankful for that. Still better than the heat pump which does nothing as far as heat goes. :)

It looks to me like that top door is not air-tight. If so, you CANNOT throttle the fire down. I don.t know whether it's possible or not, but if that were the case I'd think about getting an additional fireproof glass-fibre rope to set all around between the door and stove body, sealing it.

The door latch mechanism does not look like it would hold pressure against the door-seal.

The latch looks vertical, you see. Should be tapered.

When you look at the inside of the door, examine the gasket. Does the gasket stick out? I would want to see at least 1/4" of gasket width sticking out. To suggest that it really gets mashed against the frame, to form a tight seal.

Otherwise remove the gasket. Find a replacement gasket with a thicker diameter. Or in a pinch put some clay in the gasket groove. Then when the gasket goes back in, it will not seat as deeply into the groove.

Gotta get the door to seal tight.



Spin-off those air-vent lugs. Look at the surface of where the air-vent lug meets with their seals. Metal-on-metal? Gasket? Rust? You might want to get a piece of head gasket material, cut out a washer, so these will at least be capable of making an air-tight seal.

Thanks, we will check the gasket tonight.

If the fire rests on grates, you options are limited. To make a fire last, you get the wood to the stage of coals and then bank those coals along the side or back with a layer of ash over them except a couple of spots. That is not a good idea if you lower the draft to the point of back-puffing as there will be a LOT of carbon monoxide being created. The better choice is to use thermal mass, such as water or piles of masonry, to store heat between burns.

Your Hotblast appears to have the same knobs as my Clayton furnace, which is in its 14th year of providing non-propane heat to my house. There may be a little bump on the back of them that prevents them from being fully closed. When burning wood only one of those knobs(the bottom one?) will need to be opened a small amount. 1/8" (+/-) is all mine would need need, but will be draft dependent on your set up. The knobs can be sealed and the bump left as-is by making a 1" wide strip of aluminum foil and flattening it over the gap between the furnace and knob.

If the hole appearing to be above the bottom is not covered by the knob it will need to be plugged.

I went through the same learning curve of cutting the air intake back to a suitable level.

+1 on the door gasket too. Mine went bad after a couple years. Got one on clearance at Menards about this time of year that's been on it since. Would still be a good investment at full price.

I'm guessing your furnace is coal (requires more air) compatible?

Sounds to me like tamarackreg nailed it. Although I might suggest cracking open the vents on the door instead of the one below, the difference may be negligible.

My furnace, I close the bottom dial and leave the door dial open a crack but I also have a damper in the chimney pipe, if I didn't have the damper it would burn too quickly. I close the damper most of the way.

you should drink a quart of water before bed , then just add wood when your up to pee , have another drink every time you feed the stove , problem solved

but seriously choking down a fire to much leads to needing chimney cleaning , 3 hours isn't terrible if you could use larger wood you might get 4 try logs that just fit through the door , not a bad idea to have a box that is the same width as the door , just saying it is a real pain when you think the log will fit and you get it 98% of the way in and it won't and it already caught fire

save your elm for nights if you have any elm it burns slower

having a grate makes your fire burn faster, since the wood is not laying in the ashes. How long of pieces of wood are you burning? Split wood burns faster than large round pieces. If the door is suppose to have a gasket, that could help too. We need to see how large the firebox is......and how big is your house in sqft?
Once you get your house warm you are trying to charcoal the wood to make it burn longer.

I used to do that, but had mixed results with slowing the fire by peeing on it...
:yuck:

Thanks for all the help. No grate so that's not an issue. I actually have some nights I am able to sleep through the night and just prefer to let the fire burn out in those nights. ;) this stove is old and I really wish we could upgrade but as for now it provides heat and I just need to come to the realization it needs stoking at night. I am going to try some of the things recommended here to see if we can get a bit of an extension to our burn times.

A little green wood mixed in will slow the burn, just don't go overboard, and keep an eye on creosote buildup. Wood should be large enough to fill the firebox with 3-5 pieces. A good bed of coals built up before the final load is good too. What type of wood are you burning?Oak, hickory, and locust (among others) are good dense long burning woods.