outside wood boilers

[Brad W Wi]

I'm going to building a new home this coming spring. One thing I want is an outside wood boiler. I'm pretty ignorant as far as they go. ANY suggestions, Pro or Con will help alot. I already plan to heat the garage floor. But I'm wondering what brands are the better ones. I've talked to the so called "local experts" about it and they recomend certain brands. When I ask what brand they have, they don't even have one. I'll listen to any one out there.

[Thompson's Tree Farm]

Brad,
I have a Heatmor. It developed a leak in the boiler after 6 yrs. The company offered to weld it or provide a new one with me paying a portion. I opted for the new one. One thing to be sure of is to get highly insulated transfer piping. I had a thawed spot over my lines until I changed to the highly insulated ones. I haven't bought a drop of oil in the past 8 years!

[DOlson]

Brad,
I sell Hawken Energy outdoor wood boilers in northwestern WI. They are made in MI and have an excellent warranty. Check out the web sites listed below.

Derrick



http://www.outdoorwoodfurnaces.org/
http://www.hawkenenergy.com/

[Justin Turco]

Tarm makes a really good wood boiler. But man are they expensive. I think they are normally installed indoors. We heat entirely with wood. We use a furnace that is made by US Stove Company, purchased at TSC. But..You know,...just an observation, and I may be wrong, but it looks to me like my neighbors who use outdoor wood boilers, burn a LOT of wood.

[gmcooper]

My dad put in a Taylor boiler 8 years ago. He just replaced it this spring as the original developed a leak that was not repairable. He bought another Taylor. New one is stainless in side. His works great. It has 300+ gallon water jacket that really holds the heat. He puts wood in once a day and never is short on heat or hot water no matter how cold it gets. He burns about 5 cord wood per year running from late Oct till end of May. He does keep wood stored under cover in a shed 10' from the boiler. Before the outdoor boiler he heated with wood stove and used about 4-5 cords per winter and used electric water heater.
With our construction business one job we installed a Hardy wood boiler for the owner. The owner bought it. It was all stainless. Had only 110 gallon water jacket. We used it for about a month on the job heating the house. We had to fill fire box 3 times between 7 am and 4 pm and it would be out every morning. The fire box would blow back about the 2nd or 3rd arm load of wood you thru in. That was following the manufactures directions on firing it. What way to loose eyebrows if you were not carefull. We burned a cord of wood per week with that unit and the oil boiler ran quite often to keep the temp maintained on cold days and certainly at night. That Hardy unit wasn't worth its weight as scrap.
Mark

[Haynes Forest Products]

Brad
There is a place in Campbellsport Wisc that sells wood boilers They were great to work with. I got a 50 plate heat exchanger from them cheap there no is 877 3390061. If you go Ebay and go to the plate heat exchanger site and look for the buy it now sites you can get to the web site.

[royalmaple]

I have a central classic, a few others on here have the same and I think we are all in agreement that it is amazing. I know I'm very happy I bought it. I've had the same fire going since last november. I wasn't going to run it during the summer but I did.

I've actually come up with a way to save even more in the summer. Heat isn't an issue so in order to conserve more. I have the outdoor boiler's circulator on a timer, 5am-7am on, rest of the day off, 5pm - 7pm on, rest of the night off.

The only thing we have to do is turn on our boiler switch in the morning during the 5-7 range and shut it off before we head out to work in the morning. In the evening if we need hot water for anything we flip the inside boiler switch on and bingo.

I was amazed that during the day with the circulator off the radiant heat in the boiler heats up the water even without the draft door opening.

This will be a thing of the past in a little while when heating season rolls around.

[Maple Hill Sugarhouse]

I have a wife that thinks it's better in the long run to spend $3,000 this winter in oil/rather then me take out a weekly compensation of $ that i give her for the Account. I just spent and I'd rather pay for the $1,100 that i spent on a new woodstove for the house then oil and be compensated back to myself over the course of the next year slowly out of the checking account in a sense.

Were never usually in the same boat anyways when it comes to spending money. She likes to see the higher # and i like to see the higher savings over time. Divorce court is next.

Might be a big sugaring equipment sale next spring as i've been into 3 pow wow's about which is the more common sense move and i still can't convince her/so I'll let her wear the pant's and pay $3,000 for heat this winter and i'll put the stove in the house i'll build next year? Simple plan.

[Russell Lampron]

Like Matt I too have a Central Classic outdoor wood boiler and recommend that brand. I was planning to shut mine down over the summer but didn't. It supplies the heat and hot water for 2 houses and on the coldest days I only have to put wood in it 2 times a day.

I have been burning mostly green pine in mine since July and can go 3 days without putting more wood in. I am turning it off during the day like Matt does and will do something with a timer next spring.

Check your local ordinances first. There are some new laws going into effect in NH and maybe other states as well. Order your furnace now before the law changes if it is going to. There are only 6 manufactures that make the cleaner furnaces and they are about $3000 more than the conventional ones.

[Fred Henderson]

There are so many out there that you will become confused looking for the right one.

[Fred Henderson]

When I posted earlyer I knew of a name but could remember it. I have it now, it is called an Orlan which is similar to the Tarm. Both work on the principal of the gasification of wood. I seen and Orlan at an energy fair and it is equally as good as the Tarm. I think they are made in Poland. Both need to have really very dry wood. Otherwise a lot of BTU's are wasted drying the wood that you fill it with.

[green4310]

This will be my 14th heating season for the Hardy. Just keeps on going. Pays for itself almost every year now. Burned everything from green aspen to chair legs. Fill AM and PM. If temps get into high 40s just once a day.

[Fred Henderson]

I am going into my 8th season with my Central Boiler classic. I am very rural so a little smoke does not affect anyone.

[tapper]

Gasification boilers have been around for a long time but few people seem to know much about them. Many localaties and some states are outlawing outside wood boilers. Gasification boilers produce very little to no smoke leaving your neighbors with nothing to complain about.
Design your new home with a boiler room attached and have enough room for wood storage under roof. Even if you go with an outside boiler have enough wood storage under roof for at least 1 seasons wood. You will get the most out of the wood if it is seasoned and kept dry in any type of boiler. This doesnt apply to just the gasification boilers but all wood burning stoves.
Do a web search. Many manufacturers have a ton of info on there products and info on wood burning in general. I bought an HS Tarm a year ago and availability was the deciding factor. Tarm has sold boilers in this country for 20 + years and this also helped me decide.

[matrob]

I have a used taylor woodburner that I have used for four years. I can't figure out why it burns so much wood. I know my house isn't real efficient, but I am feeding it 3 times a day. I dug up my line in summer of 2007 and re-insulated and ran it through 8 inch sewer pipe. I know I'm not losing much if anyheat there now.

I have a water to water heat exchanger with a baseboard hot water heat system. I am running the water at about 185 F . The differential on the aquastat is set at as close as the controller wll allow as stated by Taylor. At the exchnger, there doesn't seem to be much temp. difference i the waer s it comes and goes.

Anyone with advice, experienc or ideas on why my wood usage is so high?
Thanks,
Matt

[Haynes Forest Products]

If from the boiler to the baseboard heaters there is good heat then I would say that its the fire control system in the wood stove. What is temp at the baseboards compared to the temp leaving the boiler? If the house isnt calling for heat is the stove running at full throttle? If the house is calling for heat and the stove is running full out then someware the heat is not exchanging properly. Have you checked the temp from the boiler to the exchanger. exchanger to the water entering the house and then the water temp at the baseboard farthest from the system. find at what point all the heat loss is accuring.

[Haynes Forest Products]

matrob If I read your post right you say that the temp at the exchanger is the same going in as coming out then your not getting a good heat transfer to the baseboards with that said is the circulator pump on the baseboard side working. if so is the system noisy? If it is has a valve been closed down by mistake. Some systems have tempering valves between the supply and return lines and they need to be adjusted right and dont ask me adjusted how until you know if you have one. Some times they are as simple as a ball valve. TELL US MORE

[gmcooper]

Matrob

My dad has a Taylor. What he does to control the amount of wood he burns is on the side of the blower there is a slide cover that restricts the amount of air going into the blower. He keeps that closed up maybe 80%. When the blower turns on it still gets enough air. Even with the blower off free air travels right thru the blower. On windy days you can feel it draw right in the opening on the blower. Also check the damper in the door as that sometimes sticks with creosote in at least partially open. He had to learn not to fill the fire box either except in really cold weather. Typically he puts in 6-8 8" diameter 24" logs and they will go 24 hours unless it is really cold or windy. He also has a covered wood shed and keeps his wood dry same as you wood for in indoor wood stove. Any of the outdoor boilers are far more efficient with dry wood.
Mark

[Russell Lampron]

Is your boiler rated for enough BTU'S to meet the demands of the house. When I bought my Central Classic I was told that if the furnace was too small I would have to add wood too often. The one that I got is rated for 500,000 BTU'S, I heat 2 houses with it and in this cold weather I only add wood 2 times a day. I am burning green pine and anything else with bark on it too.

[matrob]

Guys,
Thanks for the quick replies. I installed this entire system myself after doing quite a bit of research. As for the tempering valve that is mentioned, I don't have one so to speak. Is the purpose to slow the speed of the water coming and going from the exchanger on the boiler side? I have often thought about trying this, as I have several ball valve in the lines to isolate just about everything but worried about excessive pump wear (perhaps his is not an issue?). There is no problem in exchanging heat to the exchanger or the baseboards. There are several butterfly-type tempering valves in the house side of the system. I have adjusted them according to our heat needs.

The system is set up to circulate water constantly to the house through a loop in an open system on the boiler side. It goes throug a home-made side arm heater for my hot water and then to the heat exchange for the house heat. The closed system loop on the house side is set on a thermostat that cycles it's pump according to the heat needs of the house. There is very little difference in the amount of wood burned from approx 32 F down to 0F. Two full loads a day, plus about a half load in between.

Mark I have tried loading less wood and it just burns up fast and the temperature of the stove water goes down when it is burned up. The draft is set how you suggest at 80% or less, and the draft door moves freely. Taylor suggested my door seal may not be working properly, but it seems fine. ( I have re-adjusted the tension with no different results)

Thanks, your help is appreciated,
Matt

[Haynes Forest Products]

Sounds like the water side of the unit is working fine. A tempering valve works in differant ways one is to slow the water down like a car thermostat if water moves to fast it cant transfer heat efficently. Your pump will be fine as long as it isnt dead headed and that is another reason for a BYPASS valve so as the heat demands change they compensate. If all the zones are calling for heat then they shut down to 1 zone the water needs to BYPASS threw the system without over taxing the pump. Most circulators will handle this low flow. Could the wood stove be to big?

[Jeff E]

I dont think they make them to big!

I have been using a cozyburn for 5 years, it has a 60"x36"x48" burn chamber, and like the size. I heat a 3500sq' home, plus a 24x34 sugar house (38 deg, unless I am in there working, then 50) and fill once or twice a day. Each loading gets the front half of the fire box filled, and on real cold days I will fully load.

Regarding why using so much wood, it is either because you are using/losing the heat in the home, in transfer, or your stove is inefficiently burning, or you have poor wood. Wet wood will eat a lot of BTU's getting the water in the wood converted to steam and up the chimney. With poor wood, I have seen my stove run with the damper open and forced draft blowing non-stop trying to bring the water temp up 10 degrees. I have also seen it do the job in a matter of minutes with good wood.

Could you bypass the heat exchangers in the house and see if the system holds heat well? Just start bypassing things that take heat out and see if there is an area that is out of whack. I have about 150' of buried insulated tubing from stove to house, and loose about 2 degrees of heat in the transfer. The heat exchangers for water and heating the home will drop it another 7 degrees or so.

[matrob]

Jeff,
I think that's a good plan. On the next warmer day I will try isolating the exchangers and run just my loop to the house. Then, as a second test, I could also turn off the pump and close one valve at the burner to see if I am losing heat in the loop. I am really starting to think that my house is that inefficient. Last night I filled up at 8:00PM. It was set at 180F the outside temp got down to -20F. By 7:30 A.M. I was out of wood and the water temp was 125 F in the stove water. It gets a bit cool in the house on these nights.

The previous owners had the place resided and new windows installed. The outfit that did it is out of busness ( I think I know why) I can feel quite a draft at some of the windows. So I guess I'll look inside the walls sometime, as well. With our indoor woodburner for the first 5 yrs we lived here, we had a lot of chimney heat right through the middle of the house, so that helped keep it warmer in here.

I'll keep experimenting, and thanks to all of you who have helped so far.
Matt

[Russell Lampron]

From what I have read here I think that your furnace is too small for your application. What I was told was that it should be at least double the size in BTU's as what my in house oil furnace is. The 2 houses that I heat have 110,000 BTU furnaces in them. That would mean that I would need a 220,000 BTU wood furnace to heat just my house or a 440,000 BTU furnace to heat both of them. My furnace is 500,000 BTU's and I have no problem going 12 to 14 hours after filling it with wood.

If your house is drafty and poorly insulated I would start there in trying to get a longer burn time. I don't think that you have a circulation problem.

[TapME]

I would think that you only need a heat exchanger for the hot water use in the house, other than that your boiler should feed direct to your baseboard heat system. The only thing that changes this is if your local codes say different. A lot of energy is lost and or not used in the exchange process.

[matrob]

I had originally considered running the water directly to the system. However the Taylor is unpressurized and my indoor system is pressurized. Taylor said that today's pumps would pump the water through my house, but I was not convinced. This also helps me keep the 2 systems separate so that if something goes wrong with either side, there is a way to isolate the problem. My plate style heat exchanger seems pretty efficient.
Matt

[Russell Lampron]

My outdoor furnace is a non pressurized system too and I have mine plumbed right into the house furnace in both houses. There is a valve that pressurizes the house system that has a lever on it to turn it off so the house system doesn't build pressure. The outdoor furnace can be isolated easily by closing the ball valves on the feed and return lines. I have the temp controls on the oil furnaces turned down to the minimum settings and when the houses call for heat the circulation pumps come on to run the heated water through the baseboards but the temp is high enough so that the oil burners never come on.

[Haynes Forest Products]

How do you maintain water in the system if you dont have a feed line with a low pressure fill valve. Without a feed valve with constant low pressure water the system will eventualy run out of water and start to vapor lock. Water under pressure is more efficent. You also mentioned having inlet and outlet valves to the boiler. If i read that right that is a recipe for disaster. Its against code to have a valve on the discharge side of a boiler. Do you have a vacuum breaker or check valve on your water inlet?

[Russell Lampron]

I put in my shut off valves the way that Central Boiler recommended. They are always open and would only be closed if the system was shut down for repair. I have a site tube on the boiler so that I can check the water level. If I have to add water to the system I flip the lever on the pressure valve while someone watches the level on the furnace. Surprisingly it doesn't use much water. I also have automatic bleeders on the pipes in the house so that any air in the system will bleed out and have never had any problems with vapor lock.

[Fred Henderson]

I put in my shut off valves the way that Central Boiler recommended. They are always open and would only be closed if the system was shut down for repair. I have a site tube on the boiler so that I can check the water level. If I have to add water to the system I flip the lever on the pressure valve while someone watches the level on the furnace. Surprisingly it doesn't use much water. I also have automatic bleeders on the pipes in the house so that any air in the system will bleed out and have never had any problems with vapor lock.

I don't give a hoot what central boiler says. You had better make sure that the fill valve can never be accidently left open or fail and that boiler water could accidently get into your domectic water supply. You could end up with a lot of sick people or even worse. There is a device called a back flow preventer and they are not cheap but they do protect lives.

[Haynes Forest Products]

Im only adding this information with the idea of passing on the info so others can learn and not to pick on someones system or ideas. I to got fancy with the shutoff valves and had a plumbing inspecter stand there as I removed the valve from my discharge side of the hot water heater. He said he wasnt leaving with it in place. Its called the perfect storm,homeowner shuts both valves thermostat fails and pressure relief fails to open and holly hell breaks out! I know what are the chances. With that said I also want to learn. I was not aware of non pressurized systems. Russell I would assume that you dont have an expansion tank? and that you have a pressure relief valve. I know that a system under pressure works better than a non pressure system. Were only talking 14-20 PSI so its not alot. Fill valves generaly only supply water at 14 PSI. What I would do is remove the handle from the valves that you never want some helpfull father inlaw touching things. I would remove handle and hang on a nail out of view.
Now for the backflow...Granger.com Cat No 4A810 1/2 FNPT WATTS $53.45

[OGDENS SUGAR BUSH]

HAYNES
that is what makes a perfect disaster 2 or 3 things to go wrong


RICH

[Russell Lampron]

I do have a back flow preventer and the house system has an expansion tank and pressure relief valve. The hot water heater is a coil inside the oil furnace boiler. It does not have a shut off on the discharge side at the furnace. It only has shut offs at the the places where it goes to the kitchen and bathrooms that any house would have so that repairs can be made without shutting off the water for the whole house. The outdoor furnace has a cap that just sits on the top that works as a pressure relief and vent.

The only shut off valves that were added were the ones that would close off the outdoor furnace from the house systems so that the house systems can still run with the oil burner and not have to heat the 400 gallons of water in the outdoor furnace too. At the outdoor furnace there are shut off valves on both sides of the circulator pumps and on the return pipes. I agree that if somehow one or more of the valves got closed accidentally there would be an impending disaster. I have wrapped the handles in the open positions with electrical tape so that someone would have to work at it to close one by mistake.