About to buy an outdoor wood furnace... advice?

[Thomas-in-Kentucky]

I have searched and read all of the archives here to learn as much about outside wood furnaces as possible.  But now that it is time to commit and actually buy a unit, I thought I'd revive the topic and see if anyone has any more advice to offer. 

I am leaning heavily toward the Taylor **whoops - meant to say Hardy** H4 or H25, primarily because of the stainless steel construction, because the company has a good warranty, because the compay has been in business for 30 years, because I've been able to see one in operation (for 6 years without a hiccup), and because there's a dealer within 30 miles. 

Thanks to another local dealer, there seem to be a lot of "Hicks" brand outside wood furnaces in this area.  I haven't seen that brand mentioned on this board, but there are about 75 in our county.  They have a generously sized firebox (albeit unlined, and regular carbon steel) and appear to hold a lot more water than other models - other than that I don't see anything very unique about them.

Anyone have any advice... good bad or indifferent.... about these or other outside wood furnaces?  I need to buy something soon so I can work on my house in-the-warm!

Thanks in advance for any tidbits of information!

-Thomas

[jgoodhart]

Getting a unit with oil back up would be a good choise that way if you want to get away for a weekend you don't need anyone to feed the stove while your away.

[Engineer]

Hoo boy.  I could write all day about mine.   I have a Central Boiler 5648 (which is now the 6048 model).  The only other brand I considered was Heatmor.  I looked at the stainless versions of both (I think Heatmor is only stainless, no carbon steel) and decided that the regular steel was better.  Why?  The non-stainless conducts heat better, and the grade of stainless that is used on most outdoor boilers is a fairly low grade stainless.  It will still rust.  If you do the regular maintenance required by the company, you will get 20-25 years or more out of the firebox anyway.  Unless the mfr. offers a lifetime warranty on the stainless firebox, I'd not bother.

Anyway - mine holds 385 gallons of water.  I am heating a SIP-skin timber frame totalling 4300 square feet, and it is currently being heated using only a single zone, five loops of 1/2" PEX tubing in the basement floor slab.  The basement thermostat is set at 68 degrees, and the temperature in the coldest part of the house never gets below 63 degrees.  Very comfortable.  The only problem at the moment is that with very low demand on a reasonably warm day (32 degrees or higher), there is no place for 'excess' heat to go and the boiler literally boils.  Big clouds of steam coming out the top.  That problem should go away once we start using hot water regularly (the house is under construction and unoccipied for another few weeks).   As for fuel, I am using about a wheelbarrow's worth of wood per day.  Sometimes more, sometimes I don't even bother on those warmer days.  On a 30-degree sunny day, the house temperature will hold without a demand call on the boiler.  Overnight, still with no demand, the temperature will drop 2-3 degrees.  About as stable as a walk-in cooler, which is essentially what the place is. 

For me, feeding the monster once or twice a day is worth the little effort it takes, especially to save the $6-$8 per day I have been spending on fuel oil for my current home.  Where we live now eats $2500 a year in oil and it's literally half the square footage.  Not an old drafty house either.    $2500 a year will pay for the boiler in six years and leave me enough for some really nice woods tools, chainsaws and equipment.   It's not worth the money if you're not willing to put in the effort.

I could add a lot more little comments and anecdotes, but I've only been running the boiler for a total of six months.  Two last spring and four this fall and winter.   I can't complain at all. 

[ronwood]

I have the same furnace that Engineer has. It works well and puts out a lot of heat. One thing to had to Engineer's comments is that the Central Boiler does not have an ash pan.  I have the carbon steel version also. On my second year and am happy with it. I have seen the Taylor around Mo. but do not have any idea how well it works. Heatmor and Hardy are the most prominant around here.

Ron

[BBTom]

I got my first Taylor back in '88.  Have had one ever since.  When I built my new house, I didn't even bother putting any other heat in it.  I do have a small oil fired boiler gathering dust behind the Taylor, just in case I go out of town during the winter. 

I have been impressed with the Taylor from day one, it heats my home, the hot water, the Spa, and the shed.  Oh Yea!  it heats the 2000 BDFt kiln too. 

I have the 450 I think, the small homeowner model.  Holds around 300 Gal of water. 

Look out for the ones that only hold 100 gal of water or less, they do not have a good enough thermal flywheel.

[pineywoods]

I'm lookin too, but I think I will wait on woodmizers sawdust burner. I ran what specsI have past my engineer son, he was impressed.

[SPIKER]

like othres  have said:   size matters and water volume helps stabalize the boil cool down.   also many units don't have ash pans, and what you need to watch out for is that any ash that sets long periods of time aginst steel or even SS can/will cause rusting.   keeping the corners clean is critical.   summer shut downs it is very particular to make sure the ash is all gone if you are not firing it long periods.   keeping it hot & ash dry is OK for ash in there it is when it gets cool & starts condensing moisture that it really becomes caustic...


mark M

[ARKANSAWYER]

  Taylor gets my vote.   SS is not a good conductor of heat so alot is loss up the stack.  FIL had a Hardy and does not like it.  Does not hold much water and has rusted out.  (pretty good SS I guess)   He had it 8 years and sold it this fall for $1,000 and was glad to see it go.   When I put one in at the yard it will be a Taylor.

[Bro. Noble]

We are on our third season with our Taylor and like it real well.  I'm not sure what modle it is,  but it holds 450 gallons and is made to service two houses and an outbuilding if it were needed.  I didn't shop around because I had confidence in our heating and air-conditioning man and he said it was the best.  People who have seen others comment on how well built it is.  Ours is hooked into the duct work along with an electric furnace/heat pump.  There is a heat sensor on the waterline that goes to a relay.  When the water from the furnace gets below 120 degrees,  the relays allow the electric furnace to come on.  My wife sure appreciates the unlimited supply of HOT domestic water

[PineNut]

I have a Hardy and had no problems with it. Only had it for about 10 months but use it to heat the house and a greenhouse. Also used it on a kiln that is still under construction and have been able to get the temp up to 145 to 150. One thing to consider is the location. I have mine over 100 ft from the house but in a good location for handling the firewood.  I handle the firewood on pallets that can be moved with a FEL. (see my photo gallery). If I had to handle the firewood very much, I would not have gone with the furnace.

[wiam]

I think that lots of water is good.  I have a 6 year old CB that holds 400 gallons.  I have filled the stove at 6 in the morning when it was -20f and come home to a fire that did not burn and a warm house.  There are a lot of btus stored in 400 gallons of 180 degree water.  I was told the same things about stainless by the dealer that sold mine.

Will

[Thomas-in-Kentucky]

Great advice!  Much appreciated.  Please keep it coming!

Pinenut - What model Hardy do you have?  I like your system of palletizing the wood!  I have a FEL as well, and I can see the advantages of stacking it this way - very little handling... now if you could just load the stove with one of those pallets.    BTW, the crane photo was entertaining, if not sobering!

Engineer - I'm heating a timberframe home as well... about the same size.  R-24 SIP walls, and R-50 PolyIso ceiling insulation.  Your experience is encouraging.  I have radiant tubes installed in the basement, but not on the first and second floors (yet).  House is still under construction.  Hoping that the basement tubes will be enough to heat the house up some and take the edge off while we're working inside this winter.  Question - did you use water-to-water heat exchanger or simple mixing valves when you tied your outside furnace water (hot hot) to your radiant heat water (medium hot)?

I've wondered about water storage.  The Hardy that I'm looking at stores only 160 gallons of water, whereas the Hicks stove stores a whopping 1,000 gallons of water.  But it looks like one could store additional water inside the house - so long as the Taco pump is circulating enough volume?  I haven't done the calculations, but there has to be some water storage in the 3000 feet of radiant tubing I will have as well. (albeit at a lower temperature).

http://www.hardyheater.com/Products/Specifications/specifications.html
http://www.hickswaterstoves.com/

Thanks again for all of the advice so far.

-Thomas

[slowzuki]

As a neighbour to one and in my research, buy the smallest one that will work cause when they run under part load or have the solenoid damper slamming shut all the time they smoke like crazy!  Some of the good models as far as smoke is concerned have a power induced draft fan on the stack that seems to really clean up the burn.  Also, the ones that smoke less normally have firebrick liner so the fire can burn hot and clean.

Have been looking for myself but the best wood boiler I have found has been out of production for almost 10 years.  Dr. Richard Hill from Orono Maine was involved in several water storage wood boilers that were built from the early 80's till the mid 90's but people have been burning less and less wood so companies stopped producing the Jetstream furnace.

[crtreedude]

Well, unlike others, I have don't even have dos colones worth of advice for you.   

But I think cabin fever is starting to set in enough for some folk so I won't mention why... 

[bugmeist]

I have had a Heatmor for 2 years and really like it.  We heat our house (about 1800 sq.ft) and our office/warehouse (2000 sq. ft.).

Before we installed it we heated the house with wood and also a propane wall furnace  and the office with propane hot water baseboards.  The house used about $800/yr in propane as well as 3-4 cubic cords of hardwood.  Domestic hot water was propane.  The office/warehouse used $2200/yr in propane.

We burned around 6 cubic cords last winter and I expect around the same this year.  I agree with a previous post about getting the oil backup burner as you can go away and not have to get someone in to load the stove.

The heatmor doesn't boil the water.  It heats it to 180' F then shuts off the electric fan/draft.  When the water drops to 155'F the fan starts up again.  As the firebox is airtight when there's no draft there is just a wisp of smoke coming out the chimney. There is a pump that runs all the time circulating the hot water.  We haven't noticed higher electricity bills so it must not draw much.

Overall we like it because both buildings are WARM!

The only downside is the extra wood I don't have a lot of time to cut, haul, stack, etc.

[Engineer]

Engineer - I'm heating a timberframe home as well... about the same size.  R-24 SIP walls, and R-50 PolyIso ceiling insulation.  Your experience is encouraging.  I have radiant tubes installed in the basement, but not on the first and second floors (yet).  House is still under construction.  Hoping that the basement tubes will be enough to heat the house up some and take the edge off while we're working inside this winter.  Question - did you use water-to-water heat exchanger or simple mixing valves when you tied your outside furnace water (hot hot) to your radiant heat water (medium hot)?

I used a copper-plate heat exchanger.   The radiant in the basement does more than take the 'edge' off - it's actually comfortable living space.  My only issue right now is 'dumping' excess heat - I'll give you an example.  It's been in the upper 30's and 40's, day and night here, since Sunday.  Yesterday morning I fed the boiler and it boiled over and steamed up.  I haven't touched it since then, checked it this morning and there is still a half-box full of firewood and the boiler temp is at 190 degrees.  I have no good way of gettting rid of the excess heat.

EDIT:  I think I've figured out how that monster boils.  The draft door solenoid kicks the door open when the boiler water temp is 169.  Usually, there's just some small coals or buried coals and a large pile of firewood that has spent several hours "cooking" (for lack of a better word), and is good and dry and partially charred.  When those coals catch and the draft kicks in, that pile of hot, dry wood turns into an inferno.  I've had flames coming three feet out the door when I've opened it up toward the high end of the draft cycle.  What happens is, when the water temp hits 180 and the solenoid shuts the damper, that fire is still so hot and no place to dump the extra heat (especially on a relatively warm day), the water jacket boils.   The residual fire/heat/coals drives that temperature up another 20 degrees, even without a draft.    It won't boil if either A) the inside circulator pump is on a demand call and is feeding the floor loop, or B) it's a cold day, usually below freezing.

I haven't figured out the trick to timing the feedings yet so that it won't boil on me, yet won't go out entirely so that I have to start the fire from scratch again.

[ronwood]

Engineer,

Have you thought of setting the temp down on the furnance to a lower temp on the days that are warm. I have not experience the problems you are having but I have a house, hotwater heater and a shed running all the time. I using force air in both the shed and house.   Also have you consider putting a smaller load of wood in the furance and let the coals burn down a little furthur.

I would think that the problem you are having would happen with most outdoor furnance. My dad has had the problem with his (aque therm) funance when the electricity goes out and the pumps can not circulate.

Ron

 

[beenthere]

Engineer
I have had the similar experience as you with my wood boiler. I partially shut down the draft opening to lessen the air intake. That way their isn't such an inrush of air. It was a matter of learning over time just how much draft opening was enough, but not too much. If I want a roaring fire, then I open the draft full.
The other thing to learn over time, is how much wood in the firebox is needed when it's not cold out, and the wind is or isn't blowing, and a number of other tricks needed to have good control and not blow off any steam, or have a cold house. Knowing your wood supply is an important factor in the equation as well.

[Engineer]

It's a learning experience.  As I said, I've only been running it for a total of six, non-continuous months, and I'm not there all the time as the house is still under construction.  Another factor is that most of what I've been burning is offcuts and scraps from the house project - mostly pine.  I have a huge pile of it that I'm trying to get rid of, and along about February I'll have burnt thru most of it and can start on some hardwood.

[PineNut]

I have the Hardy H4, 130 gallon, 180,000 BTU. Most people around here have the smaller H2, 100 gallon, 120,000 BTU. I wanted the larger one so I could put a larger load of wood in it. It also provides the extra heat for the green house and kiln. As I mentioned earlier, it is very important to set it up for the ease of firewood management. I have a metal carport right next to the furnace for the firewood. No problem to load it in the rain. I have not had any problem with boiling the water except when I failed to close one of the doors. I don’t have the domestic hot water connected yet. I just can’t seem to find that round tuit. Seems like I saw the literature on a furnace you could load with the FEL but I think it would be a bit large for a home.

[LeeB]

What do you do for hot water in the summer? LeeB

[Engineer]

What do you do for hot water in the summer? LeeB

Either feed the boiler or let the backup propane burner take over.

[SPIKER]

For the water BOILING over you need to adjust the high temp shut off temperature down a bit lower. OR go to a different type of thermostat which can sence WHERE the temp is and when it shut down sooner to prevent this.   One of the guys at work has recently changed his and now uses alot less wood as well as 0 boil overs since then.   His was a simple bulb stat and he upgraded to a better unit with beter control features...    Anyhow one other thing is to make sure you're DOOR seal is goo all way around and making contact, any I mean ANY air leaks can cause boil over too...   Also make sure all dampers are closing fully..  some use dampers on both stack and intake air, others use pressure blower on inlet and dampers on stack ect.   all of these work in conjunction to maintain temp inside the water jacket.   

Mark M

[Quartlow]

I won't be much help since i built mine, I've turned my water temp all the way down to 160 degrees. Mine gets the heat in the trailer VIA an water to air heat exchanger under the furnace. Furnace blower moves tha air across it and through the ductwork. At 180 degrees I was getting boil overs. Part of the problem is the door design which I'm working on changing. Also at 180 degrees you couldn't step on a register without getting a minor burn.

I also found burning green wood on warm days helps keep the heat down

[Dana]

Engineer, I think Spiker has answered your boil over problem, with the thermostat. I have the 5648 also and have never boiled over. Our house is 1800 sq. ft so the furnace is way over kill. I bought this size in anticipation of taking it with us to the farm when we move there.

[Thomas-in-Kentucky]

Still collecting literature, and still torn on Stainless vs. Carbon Steel.

Been thinking about all of the bad-mouthing that the regular steel manufacturers put out about stainless steel.  They tell you that stainless will fail due to cracks caused by heat cycling, but why don't the millions (billions?) of stainless steel cooking pots in use crack?  Hmmmm.  Also just read an article in one of my car magazines where they were plumbing twin turbos on a Ford motor that puts out over 1,000 hp, and they chose 304 stainless for the headers.  We're talking about an application with _lots_ of heat cycles - up to 1,000 degrees and back down.  They didn't seem concerned about stress cracking.  So what's the truth about this?

As for corrosion, I realize that chlorine will corrode stainless - saw it happen on our stainless pool filter.  But it seems fairly easy to find and use water without chlorine (and fluorine and bromine) in an outdoor wood furnace application. 

Any more thoughts?

[scsmith42]

In general, most grades of stainless steel are typically more brittle than mild carbon steel, so there may be some truth to the heat cycling comments.

I know that there are some extremely high dollar pressure vessal's made of stainless, but at some point you have to question the cost versus benefits.

Most aircraft exhaust systems are made from stainless, and they seem to crack before they burn out.  Most automotive exhause systems are made from carbon steel, and they usually burn out before they crack.  There are other dimensions that influences as well between aircraft and automotive, but it's something to ponder...

[Qweaver]

Stainless would make a good container for a heat source but not a good heat exchanger.  SS is a poor conductor of heat and that's one of the reasones that it distorts so much when heated and also why it makes such a poor heat exchanger.  If I were making my own furnace and could get the materials cheap,  I'd make the fire box from SS and the heat exchanger tubes from inconel or maybe copper or nickle bronze.  If I had to buy one, I'd get the carbon steel one.
But then I know nothing about wood burning furnace design so I'm really no help. 
Quinton

[submarinesailor]

I don’t know what type of stainless steel is used, but most pressure vessels in nuclear power plant are stainless.  Don’t recall any problems with heat cycling causing cracks, but I do know about something called ion inbrittlement.  Expose SS to gamma and neutron radiation for long periods of time and they will became brittle.  Causing cracks in all the wrong places – don’t ask me how I know.

Bruce

[Engineer]

Engineer, I think Spiker has answered your boil over problem, with the thermostat.

Indeed, he did.  I adjusted the set temperature for the entire system down 10 degrees.  Now the door damper opens at 159 degrees and closes at 170 degrees.  I have had zero boilovers, the highest the water temperature has gotten has been about 182 degrees (warm day) and it's true, I'm using less wood.  One heaping wheelbarrow load of wood will last 2-3 days, more if the day temps hit 40+ and the sun is out.

Regarding Thomas's thoughts about stainless - I'm no metallurgist, but I think that maybe the heat cycling is less likely to affect higher grades of stainless than the really-low-grade stuff that seems to be in those furnaces.  If you've ever paid upwards of $200 for an All-Clad saute pan or stock pot, you better hope it's premium grade steel.  I have 40-year old Farberware pots that we use daily, sometimes twice daily, and a routine dishwasher cycle and the occasional scrubbing with Barkeeper's Friend is all they ever need to stay perfect.  On the other hand, I have some cheap "stainless" cooking utensils that regularly rust, and I'm going to toss them.  Not the same stainless, I'm certain.   I have also observed that heat cycling will distort most pots and pans to some degree, but the large surface area just means routine expansion and contraction and no cracks.  

[Fraxinus]

Whatever you do, make sure you do the best job possible installing it, in particular the underground piping to the house.  When my son and his (then) wife built next to us in '99, I bought a Central Boiler.  Not the pallet burner but the other big model.  Big enough to heat both places.  But I kind of slap-dash put my stuff in the ground and it was WAY too far away from both houses.  Especially his.  And it set lower in elevation than both places, necessitating that the circulators be on the unit rather than in the basement with easy accessibility.  I would definitely NOT do that again.  What a royal pain dubbing with those things outdoors rather than in a warm dry cellar.
Also, those earlier ones had a weakness in the weld around the door and it sprung a leak.  I understand that that problem has been corrected.
My son and his wife split up about 3 years later and he got the heave ho, so there went the help getting the wood worked up and keeping the fire going.  I kept it going one more winter , then told my DiL she would have to get a furnace of her own.  It's a good thing I did because she wouldn't have been able to get financing on the house to buy my son out if she didn't have a furnace.
Anyway, my advice for you would be to go with somebody you trust; somebody that knows his product and will be there with advice, parts and anything else you may need.  I'm too decrepit to want to get back into the firewood bidness again.  I kinda like going over to that Rinnai propane heater and drying out my mittens on the nice warm draft that comes from it!  If I did get back into the wood bidness, I'd sell the wood and buy propane with the money!

[jgoodhart]

At work we use to have dye kettles, they were for dying carpet. I don't know what type of stainless they were made of but they didn't rust and they all cracked at one time or another and a real pain to fix. The cycle time was about 3 hrs they would go from a heavy boil down to whatever the water temperature was in the city pipes. I would go with carbon steel and keep the water treated so rusting wasn't a issue.

[Warren]

Folks,

I appreciate reading all of the discussion on this topic.  I do not have an outdoor wood boiler.  But am putting serious thought into it.   While the $$$ from selling slabs and firewood is nice, I'd rather be using it to heat my own place and not paying for LP gas.

Fraxinus brought up a good point of going with a dealer that you trust and is local to provide service and support if needed.  For what ever reason, the outdoor wood stoves do not seem to be very popular in our part of KY.  the closest CB dealer is about 3 hours south of here. 

Anyone familiar with a boiler dealer in the Lexington/Louisville/N.Ky area ?

Warren

[Cedarman]

For those of you near Madisonville, Ky, Woodmizer is working on an outside sawdust burning stove.  I looked at it last week and I like the idea.  They may need some people close by to try out these stoves when they get them a little more developed.  They will burn green sawdust.  You might give Scott Laskowski a call. 

[TexasTimbers]

I read that with great interest Richard in this months issue. Local or not if they need testers I will come get one if they are discounted enuf!

[SPIKER]

hi all:

just wanted to say a little about SS vs Carbon Steel:

both have nearly identical heat transfer so thinking that makes a diff, not work calculating.  SS is in different grades, 3 series (304, 309, 316) lower # less rust resistant, same for 4 numbers.  which are farther down and less rust resistances but higher crack resistance.

I am not sure if there are a many MFGs using the 3 series of SS 304 good, 309 better and 316 is basically surgical steel/ 

Inconel sure is good stuff but is basically designed for very high temps, upwards of 2500 degrees F if I remember right.  nothing you need in a stove which is 180 degree water temp.

remember the STEEL  material of a stove that is in contact with water is going to be the temp of the water + a degree or less.   HEAT from the fire warms the steel through convection & radiation and the water is warmed by the steel which is in direct contact with the steel.   You can put you hand into a pan full of water and put it on the stove, as long as the water remains between you're hand and the steel you won't get burned untill water temp is over 144 degrees F. that is.  you can put 2000 degree flame onto the steel it will not boil the water until it heats the water up and this is Dependant on HOW MUCH water there is.   a drop in the bottom of a hot pan boils fast, fill the pan it takes longer (and if ya watch the pot it won't ever boil ) .

anyhow  SS is basically for rust preventative not because it is better or worse for heat conduction.   I built a good number of SS industrial washers, ONE had a crack from heat cycling, 165~180 degree water temps, and it was after 9 years in operation.  it was my design and after seeing HOW it went later on I saw my design flaw.  it worked GREAT but also had the flaw (heat exchanger was built INSIDE the tank, and penetrated both sides of the tank in the center wall of the tank.)  this was OK but had no room for expansion & contraction on the out side sections that were OUTSIDE of the tank wall.  on the burner INLET side (also the same side for the outlet of hot gases) was OK (hot gases were cooled enough to prevent a lot of expansion.)   BUT the other side was the bolt in heat exchanger which was removable for repair/cleaning (but have ever been needed to be done by the way.)  anyhow that section caused a lot more expansion due to much higher temps...  that made a small crack right in the corner of the tank as the exchanger expanded & contracted.   I had to re-weld it after 9 years in operation, (they tried 3 times and could not repair it)   It has held up for almost 3 more years now so hopefully the crack won't return but I think it probably will...


I want to build my own unit but just don't seem to have the time...   It would be SS 304,  10 gauge and 18 gauge thickness with insulation and siding outside...

mark M

[Thomas-in-Kentucky]

Well, I haven't bought my outdoor furnace yet!  In fact, after pricing them, I'm seriously contemplating trying to build my own.  Any self builders out there got any advice?

[WH_Conley]

Thomas, did you talk to Larry Mason? If you decide to build one give me a yell. You can't walk in Camp Dix without stumbling over a welder. Old classmate of yours (DW)is currently unemployed til weather breaks. Get him out from under my feet , he's now my SIL. He just loves it when I volunteer him for jobs, gives him something to gripe about. Only time he is happy is when he is complaining. Hey I think I will call him and tell him I volunteered him for a job, make him happy.

[woody1]

I love my hardy, 1994..If ole smokey ever lets me down I'll buy another in a heartbeat.

[Qweaver]

SPIKER stated
"both have nearly identical heat transfer so thinking that makes a diff, not work calculating.  SS is in different grades, 3 series (304, 309, 316) lower # less rust resistant, same for 4 numbers.  which are farther down and less rust resistances but higher crack resistance."

Well here are the thermal conductivity specs. expressed in W/mK.  Decide for yourself.

Stainless  18-8  (304)     15 W/mK

Mild Steel                         52 W/mK

And in case you really want to get efficient: 
Pure Copper                      401 W/mK           

I would not choose SS myself. 
Quinton        

[Raphael]

My only advice based on what's happening around here is get it installed soon before they make it illegal.

[burlman]

check out a Tarm unit. ( woodboilers.com) I have one with the heat storage tank. Burns clean, no emissions. uses smaller wood 20in. I have not used mine for a complete winter yet, to say how much wood It will need. so far roughly to arm fulls heats the 1800 sq ft. house easily for 24hrs on a single burn. and all the domestic hot water we need

[Raphael]

I'm liking that Tarm multi fuel boiler...  That would satisfy the states primary heating requirements nicely.  Wish it was a little shorter. 

[ezed]

I have a Tarm wood gassification boiler, I love it.  Efficient, uses less wood than the CB's my friends are using.  Much cleaner burn process, if using dry wood it hardly smokes.  I installed my "outside" the house, and inside my pole building.  The wood gassification process has a little fan that circulates the wood gasses to a ceramic burning chamber. The burn chamber gets 2000 degrees F they say.

[KamHillbilly]

Still collecting literature, and still torn on Stainless vs. Carbon Steel.

Been thinking about all of the bad-mouthing that the regular steel manufacturers put out about stainless steel.  They tell you that stainless will fail due to cracks caused by heat cycling, but why don't the millions (billions?) of stainless steel cooking pots in use crack?  Hmmmm.  Also just read an article in one of my car magazines where they were plumbing twin turbos on a Ford motor that puts out over 1,000 hp, and they chose 304 stainless for the headers.  We're talking about an application with _lots_ of heat cycles - up to 1,000 degrees and back down.  They didn't seem concerned about stress cracking.  So what's the truth about this?

As for corrosion, I realize that chlorine will corrode stainless - saw it happen on our stainless pool filter.  But it seems fairly easy to find and use water without chlorine (and fluorine and bromine) in an outdoor wood furnace application. 

Any more thoughts?

Isn't 409 stainless(titanium enhanched) the same that comes on newer vehicle exhaust ,Ive seen them rust out

[SPIKER]

Stainless Steel, 4XX is a lower grade than 3XX (316 is surgical, 304 will rust only slightly at seems welds contaminated spots. .)

mark

[Brucer]

First off, I'll see if I can put a stop to this thermal conductivity business. Low grade stainless alloys have about the same thermal conductivity as 1% carbon steel. Higher grade stainless alloys (the ones you hope they use in your furnace) have about 1/3 the thermal conductivity as 1% carbon steel. Look at the numbers Quinton posted and you'll see a good example. So ...

 ... it's completely irrelevant. The folks who perpetrated this little scam are giving you an easily verifiable fact that has virtually no effect on the efficiency of a furnace. They rely on the fact that most people don't have a degree in thermodynamics, and don't have any experience designing heat exchangers (I have both, as it happens ).

  short technical discussion follows

To get from the hot combustion chamber to the surrounding water the heat has to move through a thin boundary layer of hot gas to the inner wall surface of the firebox/heat exchanger; then through the wall itself; then through another boundary layer, this time in the water.

The two boundary layers typically account for 99.8% of the resistance to heat flow. The firebox walls account for the remaining 0.2%. So even if you triple the resistance to heat flow in the walls (by using a less conductive material), the overall all effect on heat transfer is less than 1/2 percent. If this really mattered, the designer could compensate by adding 1/4" to the length of a 4' fire box . In fact, the way you operate your furnace will have a much greater effect on thermal efficiency than the wall material.

And by the way, the heat transfer coefficient of the vessel walls is the thermal conductivity divided by the wall thickness. Still worried about the lower conductivity of stainless steel? Make the walls thinner -- after all, you don't have to make as big an allowance for corrosion. Manufacturer's actually do this, but only in order to keep the cost down.

    end of short technical discussion

Now some practical stuff.

Stainless steel will often "rust" at the welds. As the metal melts the alloy composition at the surface changes. Does it bother you? Brush the welds throughly with a stainless welding brush (yep, they make them -- cost a couple of bucks).

Want a crude (but simple) way of distinguishing a "high grade" stainless alloy from a "low grade" one? Stick a magnet on it. If it sticks, the alloy is a low grade stainless. If it won't stick, it's a high grade stainless (or else it's chrome plated brass ). Check out the quality of your kitchen utensils -- or get the kids or grandkids to do it .

Thermal cracking in stainless usually occurs at or near the welds because the welding process introduces residual stresses. Unless you have access to a non-destructive testing facility, your best protection is to stick with manufacturers who have been in business a while and offer a long term guarantee.

There's dozens of types of "stainless steel". None is perfectly resistant to everything. Sometimes a "low grade" one will resist chemicals that a "high grade" one won't. Corrosion resistance depends a lot on temperature, too. Pick a manufacturer with a good track record, and rely on them to choose the best material for the job.

'Nuff said.

[Captain]

Bruce, thanks for the thermodynamics review.  It was my suspicion, but now verified 

Captain

[beenthere]

Good read on the stainless.
Now, in the boiler, add the thickness of the creosote build-up that occurs (that which OWW says he cleans each year and that I never have ) when the cool wall due to the water jacket condenses the thick smoke. 

[slowzuki]

The condensing out on the cool surface is the one of the same reasons the darn things pollute so much.  They pull way too much heat out of the combustion zone so clean combustion can't occur.

[SPIKER]

Brucer:

thanks for the back up of the true info.   I stated above someplace in regards to the thermodynamics that S.S. is nearly same conductivity as Carbon Steel.   seems lots of people don't believe me anymore (that or they didn't read it all way through.)


True in all regards and true too that the buildup of inside gook is a bigger insulator than the rest of the steel vs S.S. debate.   true also that any introduced contaminates will cause rusting in many S.S.s welds stress areas ect.


Smoking though has many factors, not just how much HEAT (read B T U's) that are pulled out of the FIRE by the heating device.   Moisture in the wood, the AIR that is getting into the fire Wood Sap content, all are bigger factors than how much HEAT is removed by the furnace.     Basically the FIRE inside the standard wood stove (out side wood boiler in this case) is kept relatively cold by dampers and starving it for air (read Oxygen) so that the fire can't really BURN it is forced to smolder more than actually BURN.  left with a full opening of air and free flowing chimney the fire would burn cleaner (BUT the water temp) would go way too high as the fire temps increased..  reason it doesn't is the auto dampers keep the water temps in-line (or are supposed to that is!)    Some times a damper will stick closed or open, and a "run-a-way" happens.  This can warp/melt and or scrap out a otherwise good furnace...   most units SHOULD have a 2nd "secondary limiting device" to make sure that this does not happen, but lots of them are bypassed or not even installed.   so Never bypass you're Limiting Controller.   
Wood gasification units are nice but require the external tanks and won't run in power outages.   Otherwise I would like to have a TARM myself...   I am still looking for a good one that I can afford and will probably get one this year

Mark M

[slowzuki]

A well designed combustion zone can burn completely green wood without smoking.  Most outdoor boilers can't burn clean even with kiln dry wood.  Making a ventilation limited fire inside a big cold box will result in high smoke production no matter the fuel.  You could make natural gas or oil smoke under these conditions.  Ventilation-limited fires create all kinds of crazy long chain smokes that all those air-quality people are concerned about.

The runaway condition is actually temporarily a good thing as while the fire is initially growing it is a fuel limited fire (like a pellet stove)  of course once the whole load is involved it is again a ventilation limited fire.

A regular stove operates by starving the primary fire which is insulated by fire brick and ceramic blankets over the baffles to keep it warm.  Then the secondary air is introduced to burn the combustibles in the smoke, then the heat is extracted via the stove top.

So we can stop the smoke by burning it, which we need high temps to do, or we can make a fuel limited fire that burns extremely hot, or combos of these.

None of it can be done in a plain steel barrel with water around.  Now pour refractory cement or brick up the barrel and then we can talk.  It would also solve some of the corrosion troubles these simple boilers have had.

[Qweaver]

I don't have a degree in thermodynamics but I do have a degree that includes a semester in metallurgy and more importantly a lifetime of working in on code vessels, piping and heat exchangers.
I refuse to get into a spitting contest over things like this BUT, anyone that insists on believing that there is not a GREAT deference between the thermal conductivity of plain carbon steel and stainless is just ignoring the facts. 
Also this idea of Identifying SS as high grade and low grade is meaningless.  The various grade of SS are "high grade" for what they are designed for.  It would make no sense to try to make a knife out of 304 or a pipe out of 410.  304 and 316 are essentially the same save for the addition of MO and MN.  And so on. But any grade of 300 series SS will weld up with no problem.
Quinton

[slowzuki]

Qweaver, I think most people are focusing on the corrosion resistance of stainless as their "grading" measure.  As Qweaver says folks there are applications for all types of austenitic, martensitic, ferritic and precip hardening stainless steels. 

For example, 440A and lesser so 410 are very hard and brittle stainless that is used for knives, bearings and rifle barrels.  Whereas 409 is soft and medium ductility used in tanks, exhaust, piping.  304 is a little stronger but very ductile, common for chemical processing and food processing. 17-7 ph is used in springs among other things, very hard, little ductility.

The thermal conductivity of stainless steel is very important when designing a welding proceedure it but is of almost no importance in an outdoor furnace.  They are correct that the boundary layers and soot deposits will be the main factors.

[Engineer]

The thermal conductivity of stainless steel is very important when designing a welding proceedure it but is of almost no importance in an outdoor furnace.  They are correct that the boundary layers and soot deposits will be the main factors.

So then.....what is the reason behind using stainless of any kind in an outdoor furnace?

IF you had an outdoor furnace that was a standard make and model (let's say a Central Boiler unit, 'cuz that's what I have) - how would you go about modifying it so that it was more efficient, burned hotter, gave off less smoke and etc etc.?   I've come up with several "almost-ideas" in combination.  Lining the floor with firebrick, installing a grid of heavy steel mesh about 8-12" above the floor so that ash falls through, installing a forced air system (blower fan unit) on the door in place of the damper, adding chimney sections, etc.  I have noticed that burning very dry hardwood produces little to no creosote, burns hot, does not gum up the damper door, and produces very little ash.  It's also a much more predictable and consistent burn rate.

[OneWithWood]

.  I have noticed that burning very dry hardwood produces little to no creosote, burns hot, does not gum up the damper door, and produces very little ash.  It's also a much more predictable and consistent burn rate.

That is correct and why I try to stay ahead of the curve and dry our wood at least six months in advance (prefer a year but can't seem to get it done).  The down side is dry wood burns faster meaning you have to feed the beast more
Now that we are using larger rounds and I am not splitting like I used to we are likely going to be burning greener stuff. 

[thecfarm]

I've been looking at these for a couple years now.I'm so confused on what to get.The Heatmor has forced air draft with the style that I'm looking at.Drives oxgen into the fire box when the water temps falls to a certain temp and than shuts off when it reaches another set temp.I'm leaning toward a 6 foot one.This unit has 2 fans on it.I'm also looking at a Central Boiler.I use to have a boiler that took a 2 foot stick in my other house.Had it for almost 15 years and never had a leakage problem.I guess this was called a closed system.Never gave it a thought. I feel some of these need a higher chimmey.Some are only 6 feet tall.Chimmey on my house is probaly 25 feet from the ground.I do want to build a building for it.I want to have 3 trailers with wood on them.I want 1 trailer on each side of the boiler with long wood,6 feet or 4 feet,that would have about a cord each and than a trailer in front of the feed door that would hold all of the wood that would have to be split 2 feet long.I want this all on a slab.Something is going to happen here this summer.

[thecfarm]

I bought the Heatmor 400.This will take a 54" stick.Just couldn't swing the price of the 6 footor,don't need it that big anyways.

 

Going to put one heat exchanger in the cellar,86000 BTU's and one in the wife's garage.Will put another heat exchanger in the forced hot air ductwork for the house.Have alot of work to do to get it all ready for him to install.The wife's garage will have to be insulated too.Going to have to build a woodshed that will hold 4 foot wood.I plan on doing a lot of thinning on my land.

[thecfarm]

It has arrived.. This carrier would also make a good log hauler on the road.





This shows it in place and ready to be hooked up.






I'm waiting on 3-3 foot extenions for the smoke stack.That will get the smoke up in the air and out of my face.

[Tim L]

I have to tell you I'm Dang jealous. I have always wanted one of those . Please update with pics during the install and running.

                             Best of luck !

                                         Tim

[thecfarm]

The guy came to hook up the furnace today.Could only give me one day this week,will be back on Wed of next week.The 3 extentions are in place.Looking forward to having heat in the basement all of the time and warm floors.I do have a stove down there,but would only use it a few days a week.Having a warm garage will be a big plus too.Now I need a working garage for me.I do have another place to hook up another zone if and when I get my garage.

[thecfarm]

It is up and running.They got here at 2 in the afternoon and stayed until 1 in the morning.That is way past my bedtime.We fed them supper and whooper pies.Now the temps are in the 80's.     It is keeping the hot water nice and warm.Not taking hardly any wood at this time.No heat is being used.I think I will really like the Heatmor.I threw in a paper cup into the furnace.Opened it up a half hour later and could still see it.This is the type with the blowers for a draft.Really shuts down the fire when there is no demand.

[splitter]

Just want to put one in for Heatmor, this is the 3rd year I've had mine, no complaint. I like the way you remove the ashes. I've not had a over heating problem at all know matter how much wood I put in. I like the idea of the door containing water too. This should prevent warping. Doe's anyone know of someone that owns a E-Zee cord wood proccessor? I can buid one and have most of the main parts, motor, piston etc.don't want to go to canada  to see one. If any one knows where one is located or has a address etc please let me know. I have built several wood splitters and would be glad to share what little knowledge I have to help someone. I put a wood lift on mine and they split two or four ways hyd. Uses three hyd. valves.  Would love to see a wood shear!!!!!!!!!!!!! Thanks for your help. Splitter

[thecfarm]

I will give a report on the differant type of wood that I've been burning in my Heatmor.This is with 4 foot wood and I'm heating a 30X50 foot house,cellar,hot water,and hot tub.Temps have been in the low teens here,a few in the single digits.I have cut white maple in the morning and have burned it the same day.Don't really notice any differance than burning dry wood as far as heat was concerned.I do know it smokes alot more the first time it cycles.Than its much better.The smoke really pours out of it until it gets the sap out of it.I have also burned green pine,fir and hemlock.Don't notice it takes anymore than green hardwood.I did have some dry hardwood to try out.Much less smoke was just about the only thing I noticed from the green wood I was burning.I been burning dead softwood.This has been standing dead for some time.This is growing in a stand of dense hemlock.The trees cannot fall over due to being held up by the other trees.The wood is very light.I fill up the furnace before going to work and it will last for 14 hours.This is from dead wood.Seems unbeliveable to me,but I've been doing it.I'm very happy with this furnace.I do notice that it has a harder time to smother the fire when I'm burning green hardwood.I have alot of red coals when I open the door.When I burn dead softwood,I have opened the door and thought the fire went out.It is all black,no sign of a fire.I'm very happy the way it burns dead softwood.It does take more than burning hardwood,but I have ALOT of dead softwood on my land.No sense in walking by the dead stuff to cut the good stuff.I had some hardwood that was left over from last year.This was on the ground in tree lenght and was kinda covered up with sawdust.I think some might of been 2 years ago.Some was kinda rotten with sawdust froze on to it.I threw it in and I had plenty of heat from it.No way I could of burned it in my wood stove and got heat from it too.It's a whole differant way to burn wood.I did have a circulator go bad all ready.It was under warrenty,but still the junk they make.This open system is new to me.No need to bleed the air out.

[beenthere]

thecfarm
Any pics of your new burner after installation?  We like pics..

[Warbird]

How much firewood are you wood fired boiler guys going through per season?

[WH_Conley]

Depends on the season. Seriousley, when I had the Hicks hooked up to 2 old houses in town (5000) sq ft, it would not take any more than 2 wood stoves. I don't think it would anyway, no scientific facts involved.

[Engineer]

I used about 4 cords of wood last winter for just heat, this winter I have to do heat and hot water so I'll probably burn half again as much.

I've been burning some real junk lately - wet and ice-covered, most of it, scraps of pine, old punky elm and soft maple, five-year old apple wood, cutoffs from my timber frame, pine slabwood, cardboard.  Most of it is either rotten or wet to some degree.  I am still getting 24-36 hour burn times from a single load.  The only problem I seem to be having is that some of that wood produces so much creosote that my door damper sticks and it will eat up the whole load quick and overheat the boiler.  I lose water to steam and have to refill more often than I need to.  I spent some time last winter burning some very dry cherry, ash and hickory, and I noticed a huge difference - very clean burn, long burn times (sometimes 48+ hours) and very little smoke.  Plus no sticking problems.  Right now my wood is scattered all over the place, in the open, in haphazard piles and slab stacks, and I plan on spending some time this winter and next spring building a wood shed or two to keep it all dry and clean.  I like being able to feed the fire Saturday morning and not touch it again until Monday.  I have found it best to burn a good mix of hardwood and softwood, 50/50 or more toward the hardwood.  It burns hot and clean and burns off most of the creosote.

[Handy Andy]

  Was wonderin what length do you cut your wood?

[thecfarm]

Engineer,and what kind you have?How much you heating?I can only get about a 16 hour burn with the junk softwood that I burn.But that was with some round wood,not a bunch of differant sizes and shapes.I did get a 24 hour burn a couple times with some of the wet hardwood I burned.With mine I was told to get it on a 12 hour fill time.They also said you want to see the grates,before you fill it again.Do not let the coals build up over the grates.On the sides is OK,but keep the middle clear.

[BBTom]

Burn times go right out the window when you stuff 2000 bdft of frozen wet Poplar in the kiln and try to bring it up to 150 degrees.  Three loads a day for a week of good hardwood.

I hate to think how much wood I go thru in a years time,  The kiln always has lumber in it, the house needs heated, the water is heated, the shop floor has tubes in it, and the hot tub is heated with it.   My stove is a burnaholic. 

[farmerdoug]

Heating a greenhouse plus a house all winter can use the wood too.

Farmerdoug

[Furby]

Yup, I think the amount of wood used is really a poor way to measure things unless amount of heat required/used is taken into account with the figures.

[farmerdoug]

Furby,

My thoughts exactly.  The is too many variables not listed to get a good answer.

Farmerdoug

[Engineer]

Engineer,and what kind you have?How much you heating?

I have a Central Boiler, and I'm heating 4300 square feet of space.

I agree that burn times and quantities are directly related to heat load, but I'm trying to compare 'quality' of wood used to how often I have to load the boiler.  It even makes a difference as to where you load the boiler.  If I keep it mostly toward the front, near the door, it last longer.   I don't know why, probably has to do with air flow.  I have also found that the boiler has a tendency to overheat the water when I burn mostly softwoods.   Cutoff for the damper is 170 degrees, often it will spike with residual heat to as much as 180-182 degrees with pine, and rarely gets above 175 with hardwood.

[thecfarm]

I find that I have more control over the softwood,dry hardwood than I do the greenwood.I had a boil over with the green wood.I put too much into it.Wasn't all that much I felt.But I think it has to get the fire going so much to get the temp up,that it coals down and cannot smother it out.Like I said I have more glowing coals when I open it up from greenwood than any other wood.I have heard that you can burn greenwood in these furnaces and get heat.I just never believed it.I use to have a furnace in my other house.This was close system.It wasn't all that air tight.Was not designed to be air tight.I would put in dead softwood into that and would have it blow off at times.It could not smother the fire out when it was not calling for heat.One year I cut my wood late and I had a awful time getting heat from the green wood.The Heatmor that I bought has 2 blowers in it.I threw in a bunch of dead softwood that had snow frozen on to it.No problem at all with that.
Warbird,from what I can tell,SO FAR,I don't think this furnace will take a big amount of wood to keep my house warm.My place is about 30 X50,cellar being heated too.I feel if I was burning somewhat dry wood,I would burn about 10 cords of wood.That is really only a guess of course.I've been expermenting with differant types of wood and I really feel like I have some factors about what to do.I have to do it all a few more time,but I'm very impressed.My other furnace I would go through 8-10 cords and I was just about heating the same size space.I will probaly be burning more dead softwood than hardwood.I have alot that I want to put through it.

[stonebroke]

I had a boiler that would blow off in the middle of the night, What I did was put an aquastat in that overrode the thermostats and turned on the circulators. Until I learned how to load it it did get pretty hot some nights but it was better than blow the safety and I did not waste the heat. You could arrange it to heat a garage or shop.

Stonebroke

[thecfarm]

stonebroke,my other furnace was set up to over ride the thremostats too.I could always hear the pipes expand when it was over rideing the thermostats.Just wasn't enough.It would still blow off at times with dead wood.This system is a open one,meaning  it's not pressuried.When I boiled it over water was coming out of the top.Than I had to put some water into it.I should be all set now.I did not realize that it could not smother the fire with green wood.Like I said it can smother out the deadwood and the dry wood.Just a whole differant way to burn wood.

[Engineer]

Mine's an open system too, but I haven't had your problem of the fire not going out.  I did have my damper open/close temp set too high last winter, and I experienced 'boiling' of the water jacket.  Based on advice from this forum, I lowered the temps (159 open, 170 close) and have not had that problem since.  The only time that the water jacket boils is when my damper sticks as a result of creosote or wet wood, and that is easily solved by some maintenance and silicone spray.  I have noticed that the burn times are optimized if I keep the water level full.  Any significant drop and the water temperature tends to spike well beyond the damper close temp, and the burn time decreases.  It's a cause-and-effect problem which will rapidly cause the water jacket to steam off or evaporate.  I have a valve in my basement that gets turned on for a couple minutes per day, adds 20-30 gallons of water to the boiler.  I have water that is alkaline and does not need the pH additive, otherwise I'd be out there all the time adding the chemicals to it.   

[jackpine]

I have an Aqua-Therm pressurized boiler and in 4 years have not blown the pressure or temp. relief valve,much to the amazement of the dealer. Not sure why, maybe just lucky Really, I think it's because my damper shut-off temp. is never set above 180°f.
 Because I burn a lot of slabwood it's hard to tell just how much wood I burn in a winter. I have found that, for me, half cured wood seems to burn the best,meaning longest burn time per load. Oak slabs sawn in the summer that I am burning now are about ideal. I have about 4 face cord of very dry regular oak in the wood room that burns much faster than the slabwood or the wood piled outside in the snow that is not quite as dry. The other unusal thing is that the very dry oak produces as much, if not more, creosote than the other wood. In the owners manual it states that excessive creosote can be caused by burning small, very dry, pieces of wood. I didn't believe that at first but now I'm convinced.

Bill
 

[thecfarm]

Not much to look at,but a couple wanted pictures.Here's one coming through the cellar wall

 

I used expandable foam to seal all around the pipes and inside of them too.Then I used hyd cement on the outside to give that a good seal.Tared around the outside edge and all over it too,just to make sure.


This one is of the heat exchanger.No more than a radaitor with a fan behind it really.This is rated for 86000.Has been nice and warm in the cellar.Have one the same size in the garage.Have to get that insulated before I can heat it.
I also have a heat exchanger put into my forced air hot duct work with no fan to heat the house.I use the fan on my oil furnace as the fan.Works good,we are warm.


 

[thecfarm]

This is the view of the back of the furnace,


 


I left an extra zone when and if I get my garage.

[thecfarm]

I mentioned about building 3 trailers.I only have one done.Will be building the other 2 later.


 


I need another one just like this one and than one to haul any wood that will be split.This trailer is about 10 feet long from post to post and will hold almost a cord.Any big wood on the trailer has been cut 2 foot.The small wood is all 4 foot.I used a ½ ton truck axle,$50 and a trailer jack $20.I need tubes in the tires,$10 each.All metal I got from work that was being thrown away.It will be painted too.I park this beside the furnace and remove the wood as needed to fill it.I want one on each side of the furnace.When one is emptyed I will still have one full on the other side.

[SPIKER]

 
great idea having two trailers for the wood to set on!

around here ya can get the old mobile home axles for dang near free, old truck axles would be same.   would work great to put the wood on in the woods and pull home & park by burner.  I think I might end up doing just that    

I have the in floor feeder circuit tubing run now and waiting to get the concrete done until spring again.   will do it this year for sure just need to get all my ducks in a row.   I'm still debating what thickness of styro-foam under the crete I already have the foil reflective insulation on-hand but want to add foam boards too as it may be overkill but ya can only put the floor in once HOPEFULLY ......   Once I get that all figured out I'll have to make up my headers for # of in-floor circuits I'll need and will also add extras for hot water and upstairs forced air or baseboard, not sure which will be best.  I don't think the in-floor for wood floor is worth while on the 2nd floor so will add a propane fired forced air furnace with A coil for AC and an extra hot water coil for primary heating & the propane will be for backup.

I'm also thinking I might add some solar to the south side after reading some posts about it here & at TBN site

mark M

[Corley5]

A couple pics of my new boiler.  It's a warranty replacement.  My original one began leaking at the seams because mild steel wire was used to weld the stainless steel.  The manufacturer paid for the 1st repairs and after the second round of leaks agreed to replace the stove but they wanted to replace it with a reconditioned one.  I've heard bad things about rewelded stainless and I already had a leaking piece of scrap.  The new one cost me half of what a new would have plus my old one as a trade.  I'm pleased with my new stove it's better than the old one ever was.  It's also a Heat Master SS rather the Crown Royal brand that the old one was.  The manufacturer replaced the stove as the distibutor of the old stove wouldn't even talk to me    They still sell Crown Royal Stoves but they are manufactured by someone else.  It's been a real run around the last 6 months getting this done 

[analog kid]

Getting ready to install a Central Boiler, and I have a question.  I don't plan on running it during the summer, so should I leave the water in it over the summer?  Is it better for the unit to drain it when you're not using it for a season, or to leave the water in?

[blueox]

We were investigating Outdoor furnaces. We have a friend pushing us towards Woodmaster, but reading this thread not one of you mentioned Woodmaster...why??

Thanks Laurel

[SPIKER]

Blue Ox:

don't worry too much, about SPECIFIC models and or name brands.  looks for specific parts that are the same universally and or upgrades that you would awnt, items such as material it is made of

1.   "S.S 304 vs Boiler Plate construction" (NOT 404) if it is 404 then stick with Boiler Plate 404 is prone to heat induced cracking when there is a high degree of hot/cold on one side or the other)

2.   "Force Fed Blower"
3.   "Large Door Opening"
4.   "Large Water capacity" (some claim that they burn very hot & have no smoke usually this means that you have to have an external holding tank for a high volume of water this is good and bad less smoke is good having to buy extra tank is bad)

5.   "Water Cooled Door" (not a major plus but will save heat loss at the door and may prevent some warping 2nd best is cast iron door less warping and hardy lower cost no hoses to worry about)

6.   "Auger or Ash Pan" are upgrades usually some say good some say bad I haven't made up my mind on this one but thinking towards ash collection will be easier in long run? )

7. "Basic Size of Burner/Wood Holding capacity"  larger is better if you are burning wet stuff vs dry stuff and able to load larger amount but mostly depends on size of place you are heating...  Also effect burn times, (TARM has small holding capacity and very little water holding but is very efficient vs normal types.) 

8.   Price compare apples to apples, and dealer location is probably MORE important than actual NAME BRANDS.  this said look in close (less than 100 miles) for what you think you want then start looking at what is offered locally <25 miles.   then tell them you want something that will heat this size Sq Ft with XXXX heating capacity & see what they have to offer.

hope that helps

P.S. feel free for anyone to add to my (off the top of my head) list..


mark

[Engineer]

Going off on a tangent here.

Occasionally I have access to a lot of free pallets.  I use many of them to store my firewood on, but occasionally one breaks or gets rotten enough that I want to burn it.  It is a hassle to tear them apart and try to remove all the nails, so I hack them up enough to fit in the wood boiler and then worry about the nails later.

Well, I spent a recent Sunday hand-sorting through about 60 gallons of cold ashes, picking out nails, staples and all kinds of other bits of metal (plus some rocks) that managed to make it into the firebox.  There has GOT to be a better way.  If any of you burn pallets, do you take them apart?  How do you separate the nails?  I'd like to think that a magnet would work but it would still involve sifting through all the ash, no?

[Dan_Shade]

tossing some water on the ashes makes the metal easy to find....

[Radar67]

What do you do with the ashes? Seems to me if you used them for soil improvement or just dumped them in your woods, the nails would rust eventually into nothing.

[Engineer]

I put some of them in my compost, although I try to limit the amount.  That's where I don't want the nails.  The rest I'll dump in the woods or bury them, I know they'll rust away eventually (most of them) there's always the galvanized ones that seem to last forever.  I just don't want my tractor tires to become pincushions as a result of carelessness with the nails.  The last batch I mentioned, I took 10-15 pounds of nails and screws and staples out of the ashes, and I bet I missed a few.

[Radar67]

I use a sifter (designed for gardening) to run my compost through. You could use something like window screen or 1/8 inch hardware cloth to make a screen for the ashes. Should seperate the nails fairly easy.

[stonebroke]

Go down to tractor supply and buy a magnet on a stick. These are meant for picking up metal in a driveway but it wokrks pretty good in ashes too.

Stonebroke

[SPIKER]

we used to burn pallets as well, same problem, what we ended up doing was to use the water and good magnet method.   pour water through the ashes (while they are held into a bucket/barrel and mix into a slurry, left over wood parts will float and ashes metal sink, use the magnet to pull the metal out of the bottom of the slurry while mixing it up.   it needs to be thin enough to let the metal separate easily...   then once you think you have it all out pour watery part off into compost then the last bit where rocks/junk may still be can be dumped else where...

also we broke them down using a big spud bar with a horse shoe type part welded on end simply put the bar on the lower nailer and slide the U under the board & pry up pops board off fast leaving the nails usually in the nailer which you can burn and or remove the nails or

Mark

[thecfarm]

Spiker,sounds alot like a Heatmor.Really comes right down to dealer.I have a Heatmor dealer and another just about the same distance away.I did not like the other guy at all.I spent almost $8000 on that thing.I ask questions,I expect answers and no BS either.Don't run down all the other guys either.I went to quite a few shows and saw and spoke to alot of the dealers.The Heatmor is a very simple set up without a lot of fancy readouts and controlers.If I have trouble with mine I can go to the hardware store and buy what I need except for the 2 blowers,but I doubt both would go at the same time.One would get me by.And the circulators.I like things simple with as few moving parts as possible.The dealer I got mine from was great.Answered my questions for 3-4 years before I bought.Something about all the others I just did not care about.Just about like husky and stihl.They all get the job done.The Heatmor I saw in use too.That really helped out alot.I also spoke to a few people that had them too.

[SPIKER]

I posted above about ashes and water, also we did it in more smaller batches not the 60lbs someone mentioned!   we usually did it for not only removing metal but also putting out any embers that may have been in the bucket...   usually was done in 5 gallon plastic bucket, yes there were some holes but we had a lot of buckets, I have two brothers that do drywall    BUT the water & ashes will set up pretty fast like concrete so rise out anything that has the water slurry mix in there.  you can over flow the bucket with water while stirring as well to remove a lot of the ash/wood /charcoal chunks. also I used a old car speaker magnet screwed to a 2x2...   once satisfied it was mostly free of metal the bucket was dumped of wet stuff with some goo left in bottom. 

mark

[OneWithWood]

Getting ready to install a Central Boiler, and I have a question.  I don't plan on running it during the summer, so should I leave the water in it over the summer?  Is it better for the unit to drain it when you're not using it for a season, or to leave the water in?

Use the water treatment that comes with the unit and leave the water in.