aside from our opinions have you come up with any information, pellet burner mfgrs, or dectra ect?
Garn Boiler using Pellets
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No information at this time. I'm looking at pellet boilers or pellet burners that can be installed in a oil fired boiler and use hot water to heat a large hot water tank or tanks and or a Garn Boiler. A little confusing looking at the two forums. One being pellet stoves and the other wood boilers. Are pellet boilers in the wood boiler forum or under the pellet stoves forum ?
You are correct, the Effecta is designed to do this. I know Morgan up in Alaska has this set up. Tom is correct though, you have it set up for either wood or pellets - it can not automatically switch from one to the other. My understanding is the swapping between the 2 is fairly easy and quick but I have now real knowledge. They also make an awesome pure pellet boiler if you decide to go that route.
heaterman
Minister of Fire
There are numerous problems with converting a Garn to pellets.
The main issue I see is keeping flue gas temperature up where it needs to be. Given that pellets are far "dryer" fuel than wood, 1/2 the problem is solved.
The other part of the flue gas issue is you can't simply throw any old pellet burner in a modified door and expect good performance.
The problem is the heat exchanger surface area in the Garn. It is much larger than a normal residential pellet burner like the pellex will be able to "fill".
By "fill" I mean provide sufficient flue gas temperature to stay above flue gas condensation point.
Garn gets away with burning wood into low water temperature by very good combustion process and a lot of excess air in the mix.
If you're going to attempt it see if you can find a pellet burner rated to flow a minimum of about 400-450cfm of combustion air with the corresponding fuel feed amount.
Or....take the Tennman approach.
The main issue I see is keeping flue gas temperature up where it needs to be. Given that pellets are far "dryer" fuel than wood, 1/2 the problem is solved.
The other part of the flue gas issue is you can't simply throw any old pellet burner in a modified door and expect good performance.
The problem is the heat exchanger surface area in the Garn. It is much larger than a normal residential pellet burner like the pellex will be able to "fill".
By "fill" I mean provide sufficient flue gas temperature to stay above flue gas condensation point.
Garn gets away with burning wood into low water temperature by very good combustion process and a lot of excess air in the mix.
If you're going to attempt it see if you can find a pellet burner rated to flow a minimum of about 400-450cfm of combustion air with the corresponding fuel feed amount.
Or....take the Tennman approach.
It took this thread to get you out of hiding, we've missed you all winter! If the water temp is maintained at say 165, and a jr or a 1500 gal size garn was used, with a larger output pellet head and cfm maintained per pellet head firing requirements, I can't see any more harm than a unit burned with 1 year old wood, warranty aside. Or as you say tennman's system.
I think if you could monitor the humidity in the flue that would acct for the condensate action present while burning firewood and see what it is when burning pellets.
Fred61
Minister of Fire
Wouldn't that give you a false reading if a good share of the moisture has already condensed on the heat exchanger walls?
i guess it would be good to monitor both sides of the hx tubes, but the hotter the process gas the harder to find a suitable sensor. The method for hot process gas usually incorporates a dryer to remove condensate so the gas doesn't contaminate the analyzing sensor, this negates the purpose. So unfortunately you would need to check where the fluegas is in the sensors range.
One way of looking at it is that it is just another burner. They do burn well and are compatible with some oil fired units as a retrofit.
Check it out.
https://www.concordfriendsmeeting.o...JanfireNHInstallation&ServiceInstructions.pdf
Looks like the unit has robust electronics, doubtful this experiment will get any traction for the reasons heaterman expressed. Those reasons translate into warranty issues, and misused design Philosophy that no company wants to invite.
However thinking inside the box can get boring, I still believe with a high enough output, and maintain a high enough tank temp to maintain flue temps with draft requirements it might work. The possible effiency loss operating this way might not outweigh the convenience the op was looking for, but that would be his call.
However thinking inside the box can get boring, I still believe with a high enough output, and maintain a high enough tank temp to maintain flue temps with draft requirements it might work. The possible effiency loss operating this way might not outweigh the convenience the op was looking for, but that would be his call.
heaterman
Minister of Fire
Provided one could find a pellet burner...
A: capable of about 250,000btu output,
B: that could be fit up on a Garn door or something field fabbed,
C: that is able to work with the Garn combustion fan
One would still have to find a way to deal with the fact a large percentage of the pellets would be sucked right out of the combustion chamber.
And figure out a way to clean it and the flue tubes.
I don't think a person would have a problem with condensation as pellets are soooo dry to begin with. Flue gas dew point would be down around 110-120* so stay above that and you'd be OK.
And Tom....I just haven't had the time to visit here often over the last year. Work is absolutely crazy and we had a number of issues just plain old life related issues to deal with.
Wish I could be here more. It's 9:30PM and I am just getting done for the day. It's been 13-15 hour days since last fall. non stop and I haven't had a day off since august of last year....if that tells you anything.
My butt be draggin...
A: capable of about 250,000btu output,
B: that could be fit up on a Garn door or something field fabbed,
C: that is able to work with the Garn combustion fan
One would still have to find a way to deal with the fact a large percentage of the pellets would be sucked right out of the combustion chamber.
And figure out a way to clean it and the flue tubes.
I don't think a person would have a problem with condensation as pellets are soooo dry to begin with. Flue gas dew point would be down around 110-120* so stay above that and you'd be OK.
And Tom....I just haven't had the time to visit here often over the last year. Work is absolutely crazy and we had a number of issues just plain old life related issues to deal with.
Wish I could be here more. It's 9:30PM and I am just getting done for the day. It's been 13-15 hour days since last fall. non stop and I haven't had a day off since august of last year....if that tells you anything.
My butt be draggin...
Steve, I figured something was up, sorry to hear you are that busy, with the heating season approaching doesn't seem like you're going to get any rest. Did your boys get a vacation?
heaterman
Minister of Fire
The boys haven't had much in the way of vacation time either but they have been getting a Saturday off fairly regular. They've been shouldering a lot of the heating related installations and are doing great.
Kathy and I decided to start a new venture and are building an adult foster care home. (The rumors a person hears about retiring have proven false for us)
All the pieces to that puzzle just kind of fell on the table in front of us and we decided to run with it.
Mom passed away this spring after spending the last year of her life in and out of a similar facility and it just drove home to us that we need something like that in our community so folks don't have to move out.
Plus...the wife and I hope to have our new house framed in before winter... Ooooiieeeee!
Then, we might think about slacking up just a bit...Maybe going back down to a 50 hour week.
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