Outdoor Wood Furnaces

[Corley5]

My Dad and I are going to install one at his place to heat their house and the workshop.  He's getting a Heatmor.  I've been looking into them myself and am thinking of an Aqua-Therm.  They are available without the housing for installation in a woodshed or other out building.  I've got a 16'X16' pole building that serves as my woodshed now and that is where I want to set up my heating plant.  That way I can go in and be warm and dry while firing my stove.  For wood storage I'll add a leanto on to one side of the shed.  I've also requested lit on Central Boiler, Taylor, Mahoning, Wood Master and Heatsource1.  I know some of the members here have outdoor furnaces.  How do like them and which brands do you have?  Any drawbacks to them?  Do any of you have a dual fuel model that will run a fossil fuel besides wood?  Dad fell in love with the Heatmor.  A neighbor has one and he really likes his.  I like the Aqua-Therm because of it's availability without the shed and the ash auger is in the front so it won't take up as much room in a building.

[Frank_Pender]

I have two Taylor stoves.  One for the house and the other for the kiln.   8)  I have heard that there is one unit on the market that has a firebox made of stainless steel.  Apparently they do not burn out as fast or at all.  I am not a metalurgest.  but, when the firebox fals to do its job i will build a new one and simply insert it into the old system. ;D  the idea appeals to me to do such a thing.  I will have to wait and see.  I have had the one for the house five years this winter.  I heat a 3,000 sqft shanty. I use the other for just the kiln, but have dreams of having that unit pull more of  its weight in value sometime in the future. :

[ElectricAl]

Corley5,

We have two Heatmor burners. A 200 and a 400.

We bought Heatmor because it was the only stainless steel unit on the market we could find at the time, 1996.

I was over at our local Heatmor distributor Saturday afternoon. He was trying out a new Corn/woodburner. Works pretty slick. Heatmor claims it will burn sawdust off a circular saw.  I am going to take some fresh Red Oak off the WM to see what happens.  

You can buy a buildingless Heatmor if you want. They sell a "warranty" insert. Or call around for a shipping damaged unit and strip the skin off.

You're going to waste a lot of heat if your "woodshed" is uninsulated and breezy.

Have you seen the Heatmor 800, wow it is huge.
It will take a stack of full size pallets right off your fork lift.

Our 400 heats the sawshop, 40 X 80 X 16, with radiant floor.
Our 200 heats a 4000' conventional kiln and a 16 x 24 x 10 wood shop.

One nice feature Heatmor has is the water cooled door. It captures heat and prevents the door from warping from too much heat.

Also, we ordered our 400 with the same tin colors as the shop. White with charcoal trim.

No major problems with either unit. The 200 runs year round, so it's seen twice the use and higher temps (180).

If you have any more questions let us know.:P

ElectricAl

[OneWithWood]

Hey Corley5,
We heat with a Central Boiler CL40.  We are heating our house (2500sqft), the domestic hot water supply in the winter and my wifes 16x16 uninsulated greenhouse.  The greenhouse must be kept above 40deg.  We are quite happy with the unit, especially the remote indoor readout and control feature.  Because the greenhouse sucks so much heat we burn about 40 rick (13.33 cords) of hardwood every season.  Guess how I spend all my free time :D

[Frank_Pender]

I will make the first guess:  keeping the greehouse  warm and the wife happy. 8)

[OneWithWood]

Good guess Frank - you just have the order slightly wrong :D

[Den Socling]

Are any of you with outdoor furnaces in areas where smoke is a problem? Is smoke an inherent problem? or is smoke a problem only when the temperature gets low enough to kick on a combustion fan. If that's the case, I can fix the problem with proportional fan control but, where I want to set up an outdoor furnace, I don't want a frequent billowing cloud!

[Frank_Pender]

Den, I just put a stop the problem of smoke entering the house in the evening or any time.  I located a 14' piece of stainless steel pipe and placed it on the stove.   This places the tope of the pipe well over the peek of the main house roof. 8) With the pipe up almost sixteen feet from the top of the stove and the stove a good 6' feet high, that put the stack 20' in the air. ;D   Then  there is not smoke entering the house through open windows for the evening of day time hours. :D

[OneWithWood]

Frank,
That must make for quite the roman candle when you burn the creosote out 8)

[Corley5]

They sound like a good deal to have.  I'm looking forward to seeing how Dad's works out.  I'm going to dig the trench to burying the water and power lines Friday.  With a backhoe.  I try to avoid shovels for that much digging as the handles aren't sized right for my hands ;) :D ;D ;)  My woodshed is kinda drafty.  It's sheathed with 1X6 spruce.  I was going to seal it up and pour a floor in it but for the what it would cost me to do that I might as well set one up outside.  Maybe.  I'm not going to do this until next years heating season so I've still got some time for suggestions, research, and observation.

[Corley5]

Here's a pic of Dad's new Heatmor outdoor wood furnace.  It's really quite a system.  The old farm house is warmer than it's ever been.  It's set up with a heat exchanger in the plenum of the old fuel oil furnace.  We've got the water lines running out the barn/workshop but haven't got the heat exchanger installed out there yet.  It looks like an LP or natural gas heater that hangs from the ceiling.  The guy we bought furnace from and who installed it had open heart surgery a while back so he's out of commission for a bit yet and we've got just a little bit of work to do out there yet before the heat goes on.  It'll probably be ready in time for warm weather. ;)




Here's a winter pic of the old hay barn that has been turned into a workshop.  The west half anyway.

[Frank_Pender]

Corly 5,  I would suggest that you put another lenght of pipe on the stack to lift the smoke up and away from the furnace.  In this way you can have a it of cleaner air if you are stokeing the stove.  :-/ Nice looking snow scape you have there.  Thanks for sharing. ;D

[burlman]

good evening all. I have been doing tons of research on this subject as well. I'm planning on installing something this spring. I here alot of complaints about smoke, huge wood consumption, alot of maintenance, and premature failure due to creosote problems. I was put onto 2 companies selling wood GASIFICATION boilers, They are much smaller units, use less wood, burn very efficiantly, and they burn off all the smoke. check them out and then decide, but I'm pretty well sold on them. "alternateheatingsystems.com" the other is Tarm, U.S.A. 800-782-9927  ......good luck...burlman

[redpowerd]

ive heard of problems with the ash auger only boring holes into the ashes and not doing a complete job, if your going for a stove in a shed, heating with water, look into a charmaster.
im sure ill settle on this stove this next fall. i havent burn one or see it run, but its supposed to be super efficient. in most cases, 4-6 cords a year in northern minn. for a 2500  sft house. id rather cut wood fer my mill rather than the wifes cold toes :D. ill put it in my shop and use a heat exchanger for the return line with a squrell cage blowing into the shop. should keep the shop around 50-55. you also dont need to have it burning all the time, all year(hot h20), just enough to keep yer h20 tank hot. www.charmaster.com

[Eggsander]

redpwrd, I've got a charmaster (an older one) to heat my shop now. I set it outside under the leanto and ran the ducting through the wall. It gave me more room inside, and less chance of too much dust in the air causing a 'sploshun.  
It really works nice, I just need to get my roof insulated to hold the heat better.
I've actually got another one I ain't using yet sittin' under a tarp out in the Minnesota shed.  ;D

[wiam]

About 5 years ago I put in a Central Boiler CL40SB after I looked at outdoor units for about 5 years.  One big advantage I found is the 400 gallon water capacity.  This will store alot of  btus.  If I get back late and the fire is low,  the water temperature can be down to 100 degrees but the house will be warm.  I heat a big old 13 room VT farmhouse and have been very warm since I put this unit in.  I put in a water to air heat exchanger where the wood furnace was in the basement and a few cast iron radiators in cold rooms.  Has been a fire in this unit since I have owned it since I heat domestic water for 2 households.  When weather is just right the smoke can be a problem.  I have about 12 feet of stack(this starts about 5 feet up)  and on some days(very rare) smoke will come down to ground.  On similar days so would smoke from house chimney.  No more chimney cleaning or fires.

William

[Minnesota_boy]

Wiam,
Does that Central Boiler unit have the 10 year rust through warranty?  If it does, start practicing your welding now as you will need to do watertight welds in about 6 more years.

[ElectricAl]

Minnesota_boy,

We have two Heatmor's. Both are Stainless steel. One has been operating 24/7/365/6yrs @180 degree.

I'm just waiting for it to "blow a nut" you might say.

Haven't seen any deterioration inside the fire box yet other than the dents from Linda throwing big chunks at the back wall.  ;D

What insight do you have for us guys getting close to the 10 year?

Even though the 10 warranty is pro-rated to 1% or something the last couple years.


ElectricAl  

[Minnesota_boy]

If you have a stainless steel unit, I don't have anything to say.  

Mine was plain steel and it rusted through in about 11 or 12 years.  Just a pinhole, until i went to weld it, then I found a tapered hole that was about 3/8" at the inside.  Not hard to weld, its just that when I set her back down, it opened another that was almost through.  It took 3 tries before I got them all sealed.  Last time I found a pinhole leak, I hammered the bottom until I found the rest and fixed them all.  It's been 5 months without leaking now.

[cut2size]

I have a Hardy unit that has been heating my house and two storey garage/shop since 91.  It is stainless steel (firebox and exterior).  I developed a leak last winter and was prepared to replace the water jacket when the distributer told me to put eagle brand milk into the water.  I used a generic brand (Foodland) and dumped 12 cans into the stove.  I haven't had a leak since.  The hardy has a coal grate and a seperate ash door that can be accessed when the unit is energized.  I don't burn coal since wood is so plentiful in the Applachians, but some of my friends do with no problems.  During the winter I burn a 3/4 ton long bed truck load of wood in about 8 days, stacked as high as I can with no sideboards.  
As far as smoke, my neighbors call my furnace little Westvaco, but it doesn't come into the house or shop.  It only smokes when the blower comes on and doesn't last long.  The neighbors don't complain because the smoke disapates before it reaches their property.
David

[Gordon]

One thing that comes to mind with the steel water jackets is the ph of the water also how much minerals are in it as well. If you have hard water then rust will set in much quicker then if it were treated. Just a thought.

At work they spend quite a bit of money treating the water for the power plant (5 steam boilers). But this saves on the piping. So it's ten fold savings.

But this tread interests me I would like to have a water to air hook up in the coming years at my house. The way propane prices are skyrocketing it will be SOONER.

Gordon

[wiam]

I'm not sure, but I think it was a 6 year warrantee.  Central boiler is very anal about water quality.  A kit for testing ph and nitrate level come with the furnace and they say to test annually or after adding a subtantial amount of water.  My dealer has had his for a lot longer than 10 years and has been careful with water quality with no rust through problems.  Most other companies don't tell about water quality. Wonder if thay sell more boilers that way. : Minnesota_Boy What brand is yours? Do you use any additives in the water?
William

[Mark M]

I have an Aquatherm that is 11 years old. I run a 50:50 antifreeze mix and it has served me well. The last time I had it open there was no sign of corrosion or scale. While I don't have any experience with big boilers I do work with engine coolants everyday and hot water boilers are pretty similar. I recommend using a distilled water and antifreeze mix. If you don't need the antifreeze you could get a diesel engine cooling system additive and add it to protect against corrosion. Distilled water will prevent scale buildup which interferes with heat transfer and can cause cracks. pH needs to be well above 7.0 to avoid iron corrosion, conventional cooling system in engines run around 10. Air entry and stray current (not properly grounded ) can really cause problems. If you have any rust you need to take corrective action right away.

There are some chemicals made for boilers but I don't have any experience with them.

Mark

[OneWithWood]

Wiam is right about Central Boiler's advice for treating water.  We do test our water every year and I oil the firebox after vacuuming all the ash out of it at the end of the season.  I have never been able to scrape all the creosote off the baffles of the boiler inside the box but I do oil them generously.  The one thing I have not been able to do and I could use some advise with is removing the big square headed cleanout plugs in the back.  I cannot get them to budge.  Is there a special tool for removing these?  Should I attempt to loosen them while the water is up to temp at 185deg?  Maybe the steel constricts around the plugs as the stove cools.

[wiam]

My dealer also had me put dithermal-electric couplings under the furnace where it goes to copper to prevent electrolisis(sp) between the copper and steel.  Also all fittings inside are copper or brass.  Seamed pricey up front but if it helps keep furnace from rusting out then it will be worth it.
William