Forced air furnace user?

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DeanBrown3D

New Member
Hearth Supporter
Oct 16, 2006
193
Princeton, NJ
Just wondering how many people out there are using forced air wood furnaces, as opposed to regular stoves? I have the Charmaster Wood Controls system. Would like to discuss a few things since I have not had the system long (1 month).
 
I have the Yukon Big Jack wood furnace. This My 2nd winter with it. Live MD 2000suft 2story house well insulated. I have used 50-75 heating gal of heating fual in 2 years mostly in the fall and spring. Other then that I heat with wood. It cold now and I had forgotten how much wood I burn about 8 cuft wheelborrow load in 24 hrs.
 
Our wood furnace has been here for 20 years. 2 years ago I reinstalled it in series with the LP Gas furnace, and re-ducted the whole house. Then this year I had to rebuild the furnace inside with a reinforced flame baffle, a forced draft kit, new cast shaker grates, new firebrick, and a new flue and a new barometric damper also new baffle supports. This year we are good to go, the furnace hasn't ran once yet and temps have gotten close to 10 at night. Whenever I get time and quit being lazy, I will fabricate secondary burn tubes for my furnace. What I noticed was when the furnace was operating where its supposed to, I closed the bottom damper of the furnace and where the back of the furnace has a hole for the forced draft and a piece of channel goes over that hole to move the air sideways through the firebox. Well anyhow I shut down the primary air, and blue flames shot out where the air comes in from the back. I am going to tie into the piece of channel and route that air through preheated tubes right under the baffle to hopefully raise burn times. It already burns with no smoke. Im that kind of person that enjoys to tinker with things.
 
I used a wood-fired furnace for about 5 years, although I've been doing boilers for the past 12 or so.

What's yer question?
 
Hey all!

I just wanted to chat idly about them as I get more questions. For now, I'd really like some tips on mild weather usage - do you guys burn one big fire in the morning and let it burn itself down for the day, or do you set your thermostat to close it down after a few hours (when you leave for work), and then have it bring itself back to life before you come home? (I've tried the latter, but it seems to smoke a lot once its dampered down for the middle of the day time.

Also, how much wood do you use?

Also (last one) - do you ever burn green wood? My manufacturer tells me to use relatively unseasoned (6 months) heavy oak rounds as the weather gets colder. Says it makes for longer burns and better coaling that really well seasoned wood. This may be specific to the charmaster, which burns from above the coals.

Thanks for any tips,

Dean
 
We load accordingly to heat output. I have the forced draft but I haven't needed it too much this year. Because our thermostat is set at 72 for the wood furnace but being forced air the heat has nowhere to go but into the home. I loaded it at about 10:30 last night around the mid to upper 20's house was 77 woke up at 5:30 this morning house was 72 and the forced draft was running. Put 3 to 4 pieces in and at 9:00 the house was 75. The only time the forced draft should kick in is if the house can't keep your set temp. Our house is well insulated so we hold heat well. I don't burn green wood, and I think its a recipe for diaster especially for a wood furnace. Last year we used about 6 cords of wood, this year should use less because we fixed the furnace. Our settings for the daytime burning and nighttime burning are the same. Load a few splits, get 3 to 4 hours of good heat. At night, fill er up and get 8 good hours of heat. I let er burn at full all of the time, that way I get all I can from the wood with the gasses and smoke burning. A woodfurnace is about the only way to heat this old home.
 
When you say forced draft is that the same as a combustion blower/fan? Are your stack temps under 300?
mine are when the combustion is not running. I clean my stove pipe every 6wks or 8wks as needed.
With warmer outside temps I burn at night reload at 5:00AM a smaller load.Tthen the sun warms the house.
My wife is home schooling so they are home.They like it not to hot and not to cold. If it's 72 in the morning
it will be 75 by 4PM from the sun and will cool off by 8pm. I think I will use 4-5 cords this year.

Paul
 
The forced draft is a small fan on a thermostat upstairs that forces oxygen into the fire to fuel it up if the house drops to the temp set. Ours rarely runs, as far as stack temps, I have no idea, but would say most defiently over 300. We have a barometric damper on our flue due to a tall masonary chimney. 90% of the time when the furnace is burning only vapor comes from the chimney. I checked the flue the other day and after almost a month the buildup was less than an 1/16 of an inch. Nothing in the chimney.
 
We're near Chicago and are into our second season of using a Daka 521 supplemental wood furnace. We have it set up with the jacket air feeding the gas furnace plenum using it's own 500CFM blower. We just leave the gas furnace thermostat down at 60ish, and if the room temp drops to that, the gas furnace will kick in. That never happened last season. We started heating with wood this season on Dec 1st.

The Daka has a snap switch blower control that turns on it's blower when the jacket temp reaches 110F. Combustion air is regulated by a dial adjustable thermostatically controlled air damper on the front of the fire box. Combustion air is fed under the grate in the front of the furnace.

After much experimentation, we have settled on 8 hour burns with a flue temp of from 350F to 600F depending on how much heat we need. At 600F the Daka will heat the 1000sq/ft house at -10F with 15mph winds. Last year while experimenting we regularly achieved 18-23 hour burns, but have abandoned the practice due to excessive smoke and creosote production...had to try it.

There is usually someone at home, but if we have to leave it un-attended for a few hours, we make sure we're well into a stable burn cycle and then run the air control down to a point that will ensure a fairly cool burn and little chance of "excursions". If we're leaving for more than a few hours (which is rare), we let the gas furnace pick it up.

4.5 cords of wood lasted us the season last year, although is was 90% osage orange. This year we have more oak, so maybe we'll use more...we shall see.
 
laynes69 said:
The forced draft is a small fan on a thermostat upstairs that forces oxygen into the fire to fuel it up if the house drops to the temp set. Ours rarely runs, as far as stack temps, I have no idea, but would say most defiently over 300. We have a barometric damper on our flue due to a tall masonary chimney. 90% of the time when the furnace is burning only vapor comes from the chimney. I checked the flue the other day and after almost a month the buildup was less than an 1/16 of an inch. Nothing in the chimney.
Your set is almost the same as mine but i think my stack temp are lower when the fan not running. Just got a thermometer. With the barometric damper how far does that open. I get croastoe build up on the damper flap itself that I chip off.
 
Anybody who tells you that it's better to burn green/wet wood than dry wood in any stove, furnace or boiler, doesn't know what he's talking about.

Any water contained in any piece of firewood can only leave the system one way, and that's in the form of steam. And making steam diverts heat energy that should be going into your house and sends it up the stack as steam. This not only cools your chimney and contributes to creosote, but it translates into less heat in your house.

Just because you can get away with it doesn't mean it's OK.
 
Eric Johnson said:
Anybody who tells you that it's better to burn green/wet wood than dry wood in any stove, furnace or boiler, doesn't know what he's talking about.

I'm guessing that they are advocating less efficiency and increased creosote production in favor of a longer burn that requires less tending. If you a) Have plenty of cheap wood, b) Don't mind smoking, and c) Are willing to clean your chimney religiously, I suppose it will work, but I wouldn't do it.
 
Mine opens a quarter of the way. I dont get any creasote on mine.
 
Just burning seasoned wood is around 50% efficient and you loose 15%-25% efficiency burning green wood for reasons Eric Johnson had mentioned.

Now if you can burn the smoke / gasses from the wood your 50% wood burning efficiency goes up and this is how home stoves are getting 70% range of efficiency with secondary burn chambers and cat combustive burners.
 
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