Boiler decision made....well sort of:

[muncybob]

I guess the only decision we have made at this time is the new wood boiler will be a gasifier. Appears it will be located in an insulated shed very close to the side of our house and the wind should take care of most of any smoke for us. The situation is that for the first heating season we will be burning a lot of fairly green wood. Plan to order a truck load of wood and start cutting soon. I will be taking as much standing dead wood out of our land that I can find to help . We also will not have storage for at least the first season.

Green wood aside....what gasifier out there would be best suited for a no storage system? Or, what should I be looking for that makes a boiler better suited for no strorage when compared to others? The EKO with it's "puffing"(as Eric described it) seems to be a candidate but we are open to all input here. I realize that the combination of green wood for the first year and no storage will require more wood usage than normal but hopefully next year we have well seasoned wood to burn but storage is a few seasons off for us.

What extra precautions should I take when burning mostly green wood?

 

[heaterman]

"What extra precautions should I take when burning mostly green wood? "

If I had to burn green wood in a gasifier with no storage I think I would wait a year. I've seen people try it and give up after plugging their boiler with creosote, burning 3 times the normal amount of wood and having to constantly tend or kindle a fire. JMHO

 

[steam man]

Maybe there is a "wood hoarder" nearby who will trade some dry at a wood for your "pre-seasoned" wood (good bargaining term) for a premium. Consider it the price to get into the game.

 

[muncybob]

Yep, I have already begun my local search for wood trade off. Waiting another year is not an option for me as I would expect to pay around $3500 this heating season alone for oil. If green is my only wood then perhaps I will have to look at something other than a gasifier. The Wood Gun also looks appealing to me in that they state the creosote problem is solved by their stainless steel surface in the combustion chamber. Now to a novice like me that sounds good but is it really the answer to creosote build up?

 

[steam man]

I am in the same situation you are, sort of. I am converting over to a conventional wood/coal boiler (I am getting it for free) from a green wood burning wood stove and have about 6 cords new wood. But since PA coal is locally available I plan on trying that for at least the first year to see how it goes. That leads me to a thought on why you shouldn't hedge your bets and have a multi-fuel boiler since you live in coal heaven. If my coal burning works out I'll send you my wood from Maine and you can ship more coal to me. LOL

Mike

 

[muncybob]

The wood/coal combo is still a possibility but from what I have read you greatly lower the efficiency going to multi fuel as compared to single fuel? I also am not sure how I will work out the coal storage and if the coal is stored in my basement I will have to lug it up and out to the burner shed.

 

[steam man]

The wood/coal combo is still a possibility but from what I have read you greatly lower the efficiency going to multi fuel as compared to single fuel? I also am not sure how I will work out the coal storage and if the coal is stored in my basement I will have to lug it up and out to the burner shed.

I say the efficiency question comes into play when you try to integrate oil and a solid fuel with multi-chamber boilers. Wood or coal shouldn't significantly be different in a unit designed for it. Gassifers are much more efficient on wood alone. I just wonder how much time storing bagged coal takes as opposed to using wood.

About that lugging issue, even with wood you should have a good husky wife to take care of it.

Mike

P.S. My wife just laughed. She hates wood burning right about February.

 

[carbon neutral]

I think the wood gun by ahs is a nice choice. I liked that they are gasifiers and can be run without heat storage. The problem for me was their smallest boiler was too big for my needs and they were also too expensive. When I priced them the e-140 was $7,585 an additional charge of $2,000 for automatic oil burner back, the e-180 was $9,185 and came standard with the oil burner back up. This was the fall of 2003, at the time a tarm 40 was $5,000. I would be interested in what they cost now, I wouldn't think they increased in price at the same pace as the tarm most of the tarms price could be traced to the euro/dollar exchange rate. In 2003 they were pretty much on par with each other now at ~ $1.6/1 euro ouch!

 

[heaterman]

Yep, I have already begun my local search for wood trade off. Waiting another year is not an option for me as I would expect to pay around $3500 this heating season alone for oil. If green is my only wood then perhaps I will have to look at something other than a gasifier. The Wood Gun also looks appealing to me in that they state the creosote problem is solved by their stainless steel surface in the combustion chamber. Now to a novice like me that sounds good but is it really the answer to creosote build up?

In a word........No

 

[leaddog]

Yep, I have already begun my local search for wood trade off. Waiting another year is not an option for me as I would expect to pay around $3500 this heating season alone for oil. If green is my only wood then perhaps I will have to look at something other than a gasifier. The Wood Gun also looks appealing to me in that they state the creosote problem is solved by their stainless steel surface in the combustion chamber. Now to a novice like me that sounds good but is it really the answer to creosote build up?

The wood gun is a good gasifier but as with all gasifiers you need dry wood. They also say you don't need storage but as all gasifiers they will be more efficient with it. Start looking around for some dry wood for this year even if you have to pay more as it will be cheaper than oil and get your next years wood now. You might be able to find bio-bricks and I here they burn well and you can mix in alittle undry 35% wood.
leaddog

 

[muncybob]

Bio-bricks?? That's a new one to me!!

steam man, funny you should remark about a husky wife...wife has been wanting to lose some weight but I'm not sure she'll totally buy into this exercise program.

I'm waiting for the current pricing from AHS on the Wood Gun and we will probably make a day trip to them if the price is bearable. I only need the wood boiler as my existing oil boiler will be backup for us.

I guess we'll pay a premium price this year for dry wood...there goes my recently aquired gas leasing rights sign on bonus $$ here in PA! EZ come and EZ go!

 

[carbon neutral]

When I initially looked into gasification boilers I spoke to many owners of the various brands. AHS claims their boilers can accept up to about 30% moisture and wood that is unsplit up to 14" diameter. Those claims were confirmed by the owners of these boilers. If you cut split stack now you could be close to 30% by winter depending on wood species. The only complaints I heard repeated by the owners were that they are loud because of the relatively large fan and that the ash is extremely fine so it can really carry far from the boiler. I even spoke to the Nichols at Tarm USA and they, to their credit, were objective when comparing the AHS to the Tarms. I guess they had sold AHS boilers in the past and in the basement of their hardware store right next to the Tarms is an old AHS boiler. The reason they can take higher moisture content wood is because they have 5 times the refractory mass compared to the Tarm. This is also the reason that they can operate without heat storage more effectively, the mass of refractory will allow the boiler to cycle. The cycling did lead to corrosion problems when they were made out of carbon steel but since switching to 304 SS they haven't had the problems they had in the past. Anyway let us know what you find out on pricing and availablity, I imagine they are going to back logged like everyone else.

 

[ISeeDeadBTUs]

1) ALL wood-fired hydronic systems (traditional OWB, downdraft Euro-design, Natural draft refractory) will be more efficient with storage
2) Someone correct me if I am wrong, but . . . creosote is unburned particulate and water, which condense out when the temperature is low enough. Stainless steel is not going to keep this from happening. If a salesman told you that, he is either lying or ignorant of the facts. Not sure I'd wanna give over a boatload of cash to such a person.
3)If you're committed to doing the 'wood thing', get a unit that will work the best for you for THE LIFE OF THE UNIT, not the first year.

The closest thing I have had to a 'creosote problem' with my GreenWood is burning these past several weeks. I have has creosote run down my stove pipe when it gets 70-80 outside. For a while I was turning the aquastat back to 100* (I keep thinking I can see the top of the learning curve coming up) and the damper was completely closed for probably 9-10 hours. Since then, I have gone to setting it at 160* which can still result in 4-5 hour idles. Minimal amounts of quality wood are important. Another fix would be to force the damper to come open for 10 minutes every hour, irrespective of boiler temp. Obviously a better solution would be to get solar DHW going.

But anyway . . . the GW comes with an 8" outlet and I do NOT reduce to 6" anywhere. Thus, the creosote is not a problem.

 

[muncybob]

I should clarify the Wood Gun statement about creosote...it wasn't that they said their unit would not create it, but rather that the creosote would be formed on the stainless steel areas and that it would then flake and burn upon re-ignition????? Not sure if I have that right and I will try to get it clarified upn my visit to them in the near future.

 

[carbon neutral]

"I should clarify the Wood Gun statement about creosote...it wasn’t that they said their unit would not create it, but rather that the creosote would be formed on the stainless steel areas and that it would then flake and burn upon re-ignition????? Not sure if I have that right and I will try to get it clarified upn my visit to them in the near future."

You have it right. The SS will not prevent the creosote from forming but it does not corrode which is one of the things creosote will do to carbon steel. All gasifiers are prone to corrosion in the primary burn chamber because that chamber operates at a low temperature. One of the biggest reasons people use heat storage is that if the unit is carbon steel it will extend the life of the boiler by allowing it to operate at a higher temperature and not cycle off. One of these sites reported a tarm owner whose primary chamber started to leak after six years of use. He did not have heat storage, I don't know if he had a thermovar installed. As a side note Tarm USA did honor the warranty and repaired the boiler. The other reasons for heat storage are extended burn seasons, burn time flexability and yes efficiency. Another advantage to having SS is the exhaust temperatures can be reduced without fear of condensation on the exhaust side. Wood guns have exhaust temperatures as low as 275 degrees.

 

[muncybob]

Interesting. It seems the Wood Gun may be the ideal boiler for me since I want a gasser but I don't see storage in my near future. I have sent them an email but a of yet no reply. Hoping to make a day trip there possibly next week. It would be nice to find a current owner in Central PA though! Any info on their wood/coal combo units? I know I would be sacrificing some efficiency but the options between using either source would be the best world for me!

 

[jebatty]

Another advantage to having SS is the exhaust temperatures can be reduced without fear of condensation on the exhaust side. Wood guns have exhaust temperatures as low as 275 degrees.

I don't see a rationale for SS having anything to do with this. Presumably all gasifiers burn at about 1800F. Composition of exhaust from all gasifiers should be the same. Tell me more why SS has an impact here.

 

[carbon neutral]

Another advantage to having SS is the exhaust temperatures can be reduced without fear of condensation on the exhaust side. Wood guns have exhaust temperatures as low as 275 degrees.

I don't see a rationale for SS having anything to do with this. Presumably all gasifiers burn at about 1800F. Composition of exhaust from all gasifiers should be the same. Tell me more why SS has an impact here.

You are correct the combustion gases should have relatively the same composition after being burned in any gasifier, however if the exhaust gases have too much heat extracted or the fire is run too cool the gases will condense. Condensation from any combustion is corrosive whether it be wood, oil, or gas. The stainless steel will not be effected by this condensation to the same degree carbon steel is. Because the wood gun boilers are constructed of stainless steel they can have a very low exhaust temperature compared to many of the other gasifiers on the market without fear of corrsion. Obviously everything else being the same a lower exhaust temperature would be indicative of higher efficiency. As I had said earlier Tarm USA was very objective when I asked them to compare their products to the wood gun. From their own test results they thought the wood gun may have been slightly more efficient then the Tarm, about 2% more. I am not endorsing the wood gun just trying to show some of its positive benefits to a prospective buyer. When I fully evaluated the boilers available I realized the wood gun would not be the best boiler for my situation and chose an EKO 40 instead.

 

[carbon neutral]

Interesting. It seems the Wood Gun may be the ideal boiler for me since I want a gasser but I don't see storage in my near future. I have sent them an email but a of yet no reply. Hoping to make a day trip there possibly next week. It would be nice to find a current owner in Central PA though! Any info on their wood/coal combo units? I know I would be sacrificing some efficiency but the options between using either source would be the best world for me!

Contact Jeff at AHS he is the owner and had no problem taking the time answering all my questions. You are definately on the right track if you want to speak to owners. Ask for a list of owners in your area and they will be happy to provide you with some people you can contact. I did this with both wood gun and Tarm and they both happily provided me with a cutomer contact list. Nothing beats seeing an operational unit in a real world cutomers house and finding out their real world experiences. If there are no customers in your immediate area you can go to their factory and they have operational units on display. I don't know about the coal units, you have looked at their web site right?
www.alternateheatingsystems.com/woodboilers.htm

 

[jebatty]

The stainless steel will not be effected by this condensation to the same degree carbon steel is. Because the wood gun boilers are constructed of stainless steel they can have a very low exhaust temperature compared to many of the other gasifiers on the market without fear of corrsion.

I'm not disputing stainless steel and corrosion resistance; just trying to better understand the creosote corrosion resistance positives of the Woodgun. Are the Woodgun fire tubes also stainless? On the Tarm, gasification exhaust gases are entering the fire tubes at as much as 1800F and exiting at, in my case, 400-600F, depending on the efficiency of the heat exchange and the volume of exhaust gases moving through the tubes during the burn cycle. It seems that the fire tubes would be the primary area where creosote condensation could cause damage, or the chimney, but not the gasification chamber or the firebox, both of which are much hotter during the burn cycles.

I appreciate that a stainless firebox also may have creosote corrosion resistance, and creosote does form in the fire box of the Tarm, although it appears to be "controlled" in that it does not continuously build up, so it must be burning off to some extent during each burn cycle.

 

[muncybob]

When I fully evaluated the boilers available I realized the wood gun would not be the best boiler for my situation and chose an EKO 40 instead.

I am curious, what was it about your situation that favored the EKO 40?

 

[muncybob]

Jim, wouldn't the fact that your boiler burns full throttle since you have storage and doesn't have much, if any, idle time have a bearing on limited creosote buildup as you noted? Without storage I would anticipate in my situation the possibilty of creosote build up to be greater which is why in my feable mind the SS makes sense?

 

[carbon neutral]

The stainless steel will not be effected by this condensation to the same degree carbon steel is. Because the wood gun boilers are constructed of stainless steel they can have a very low exhaust temperature compared to many of the other gasifiers on the market without fear of corrsion.

I'm not disputing stainless steel and corrosion resistance; just trying to better understand the creosote corrosion resistance positives of the Woodgun. Are the Woodgun fire tubes also stainless? On the Tarm, gasification exhaust gases are entering the fire tubes at as much as 1800F and exiting at, in my case, 400-600F, depending on the efficiency of the heat exchange and the volume of exhaust gases moving through the tubes during the burn cycle. It seems that the fire tubes would be the primary area where creosote condensation could cause damage, or the chimney, but not the gasification chamber or the firebox, both of which are much hotter during the burn cycles.

I appreciate that a stainless firebox also may have creosote corrosion resistance, and creosote does form in the fire box of the Tarm, although it appears to be "controlled" in that it does not continuously build up, so it must be burning off to some extent during each burn cycle.

According to wood gun every part of their boiler that comes into contact with any of the cumbustion process is made out of SS, so from that I would say yes the fire tubes are SS. I do believe because you have heat storage you are not seeing much creosote build up in your fire box. Without heat storage when the boiler would need to go into an off cycle the temperature would drop of quickly and that is when harmful levels of creosote can build up. As I mentioned earlier the person who's Tarm failed after only 6 years use did not have heat storage. His boiler did fail in the primary chamber.

 

[carbon neutral]

When I fully evaluated the boilers available I realized the wood gun would not be the best boiler for my situation and chose an EKO 40 instead.

I am curious, what was it about your situation that favored the EKO 40?

1. Cost, I am getting a really good deal on the EKO
2. Heat load requirements. My house is near the ocean, even on an unusually cold day for the area I only needed an average of 37K btu/hr.. On average for the month of January the house only requires 31k btu/hr including DHW, cooking, and dryer (for laundry). The smallest AHS boiler has a reccomended heat load of 70k btu/hr. so it would be in an off cycle much of the time even in the winter.
3. I want a heat storage for more than heat storage. I plan to use it for igs water in the summer months. Because I will be using an open direct radiant floor I can use the water to cool the house. I could do this without the tank but the tank allows me to control when I use the water. I can fill the tank via a solenoid connected to a timer so it will fill during peak solar gain i.e. between 12 and 3PM but I can water the lawn in the early morning which is best for the lawn. Also the tank will allow me to use a much larger pump which simplifies the IGS system by getting rid of many of the zone valves I would need, makes it cheaper too! I can use the tank to catch rain water from the roof as well saving some drinking water for drinking.
BTW I found a customers phone number who owned both a carbon steel AHS and now has the SS model. He has been using the products for more than 20 years and has lots of experience with them. If you e-mail me your e-mail address I can send you his number. He lives in Barre, Ma so I doubt you will be able to visit him but he does have a lot of good info.

 

[kshultz]

Something you can do is ask around everyone you know to see about taking down dead trees. Dead trees that are still standing may not be a bad idea. A neighbor had a dead tree taken down from the utility company, I went over & picked it up. It was a large tree, I got about 1-1/2 cord out of it. Although some parts were too far gone & other parts were eaten out, FREE & dried is better than no tree. Just make a point to ask around, I'm sure you will find something.