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.

jebatty - 02 July 2008 07:50 AM

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.

muncybob - 02 July 2008 07:34 AM

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?
http://www.alternateheatingsystems.com/woodboilers.htm

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.

clarkharms - 02 July 2008 08:50 AM

jebatty - 02 July 2008 07:50 AM

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?

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?

jebatty - 02 July 2008 12:58 PM

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.

muncybob - 02 July 2008 01:49 PM

clarkharms - 02 July 2008 08:50 AM

jebatty - 02 July 2008 07:50 AM

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.

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.

muncybob - 30 June 2008 07:23 AM

The EKO with it’s “puffing"(as Eric described it) seems to be a candidate but we are open to all input here.

If its puffing the draft can be wrong.
One guy here have that problem but solve it whit a thing that keeps the draft steady.
I don’t now the english word for it.

Here a video of my when its windy outside.
http://www.youtube.com/watch?v=cEycuK_9Zb4

The other thing that can cause “puffing” is if the primary and secondary air is not in the right ratios.  From what I have heard drier wood requires a larger percentage of secondary air, can anyone with a gasifier confirm?  I think this is the problem Eric actually had as he ended up adjusting the secondary air.  I believe on the Tarm it is a relatively easy adjustment because they have provided a knob by the upper left of the gasifcation chamber door to do this.  On the Eko it was a more complicated adjustment and I don’t think it could be done with the unit in service.