Garn Boiler using Pellets

[Flathill]

Has anyone hooked up a pellet burner to a Garn Boiler. Seems like it would be nice to be able to burn fire wood or wood pellets in a Garn Boiler. A new door or modification to the door to the fire camber would be needed.
Also fan combustion air adjustments would be required.
I would like to have my separate Boiler House hot water system that feeds two other buildings to have more than one fuel option. Sometimes obtaining or having dry wood on site can be a problem.

 

[TCaldwell]

Sounds interesting, I'm sure with fabricating a new door, to mount the head would be easy. A little investigating on the pellet combustion make up air would be in the burner specs, as some are sold to retrofit existing oil boilers. Depending on your house load the firing rate might not have to be large.

 

[mike van]

Can you just throw a bag of pellets in the Garn & fire it up? See how it burns or not? Otherwise the blower on the Garn would have to be running continuously to carry the heat of a small amount of pellets fed into it? Could you have a stand alone pellet boiler plumbed into the Garn water to keep it hot? I'd do a lot of calculating before I cut a hole in my Garn door.

 

[maple1]

I'm thinking you'd have a really low flue temp.

 

[TCaldwell]

A small booster fan in place of the inducer fan might be all you need, however the garn through convection drafts about 4500btu/hr when the inducer is off, not sure what that equates or cfm. I would think the pellet head mgr could recommend a draft requirement, easy enough to convert to a cfm. A small vfd fan Reostat could keep that in check. Honestly in my case with the outdoor reset temp plus a little could be max storage temp in the garn tank. I still think you could get away with a 75k btu firing rate for the pellet head. Just thoughts

 

[TCaldwell]

Mike, look up 02 controlled garn on YouTube, fabricating a door is easy

 

[Fred61]

There could be another issue. I don't know a lot about a Garn but it appears that unlike many other boilers that have that upright column of air we call a stack to move the gasses from the unit, the Garn relies on the combustion fan (blower) to also exhaust the gasses as witnessed by the horizontal flue pipe.

Burning pellets would require a smaller fan for combustion and probably would not be adequate for clearing such a large space of the gasses produced by the combustion of the pellets. Your opinion?

 

[velvetfoot]

Would the pellet burner be something like this?
http://pellxusa.com/pellx_burner.html

You'd have both forced and induced draft fans. Do they have to be balanced?

 

[TCaldwell]

Funny you should mention pellex, just talked to him they have a model 30 that modulates from 50-100kbtu/hr. Thinks it would be a good fit, there is a contact that would close to turn on a external draft booster if needed. It really doesn't modulate but has preset firing outputs, that would make a boost fan easier to nail down in place of the garn draft inducer

 

[TCaldwell]

The problem I see with the pelex is the minimum dt is 50 deg, so if it stops firing at 160, it won't fire until it's 110, 100 btu/hr won't cut it, defeats the purpose of a lower firing rate

 

[TCaldwell]

The peltech uses a owner supplied aquastat for on off temps

 

[TCaldwell]

Smokeless heat sell pellet burners also

 

[velvetfoot]

Their "thing", though, is to replace an oil burner, where there's a flame that hits a target wall, etc. How much of a match would this be for the Garn?

 

[Buzz Saw]

Can you just throw a bag of pellets in the Garn & fire it up? See how it burns or not? Otherwise the blower on the Garn would have to be running continuously to carry the heat of a small amount of pellets fed into it? Could you have a stand alone pellet boiler plumbed into the Garn water to keep it hot? I'd do a lot of calculating before I cut a hole in my Garn door.

I would think the pellets would get sucks into the flue. When my Garn is burning once in a while I can hear some "charcoal " hitting the fan. There is a decent amount of charred wood in the barrel

Sent from my SM-G900V using Tapatalk

 

[Gasifier]

Are you just talking of supplementing pellets in the burn chamber along side or mixed in with the wood? Or having a constant feeding mechanism for the pellets?

I have burned pellets in my Wood Gun. But I know the Garn is a different animal. And a nice one they are!

I would just wait until I had a nice deep bed of coals and throw in anywhere from 1/2 gallon to a gallon of pellets in along with splits of wood. I had the pellets from a good deal I got for the pellet stove at camp and decided to supplement my wood supply.

So if your supply of dry wood is low. Could you just toss in cardboard milk half gallons, full of pellets, when putting in some splits?

 

[TCaldwell]

i believe the op is talking about a pellet burner, not just burning pellets around cordwood, upon talking to pelltech a burner distributor, this is doable.
The garn burn chamber size lends well for heat transmission and cleaning, just need a dedicated door to interface the pellet burner head, the change required would be matching the draft requirement of the pellet burner through the garn. Most likely requiring a different inducer with less cfm, this should not be difficult, and a tuning of the pellet combustion with a portable fluegas anlyser. The only other issue i see might be very low flue temps, and this depends on burner output and tank temp to be maintained.
I will make a standing offer to test the viability if someone can come up with a pellet burner/controller for a month. I have all the fabrication stuff and testing /tuning equiptment. The burner should have a output of 100kbtu/hr or better and run on 60hz

 

[Tennman]

Doesn't sound like you have the Garn yet, correct? I'm basically running and doing today what you want to do. I enjoy burning wood so last nite (Friday) I started a fire in the BioMass and will run it until it's last load Sunday nite. During weekends or holidays the BioMass feeds storage. Sometime Monday morning storage will get down to a mid-tank temp of 135F and the Windhager pellet boiler takes over during my busy week or when I go on travel or get lazy. Since now 80% percent of our winter heat is coming from pellets, 80% of the system value (cost) is invested in the Windhager pellet boiler. If you know going in pellets will be you primary heat, I'd buy a high quality boiler designed for pellets and an inexpensive wood gasser both feeding storage. Certainly the Garn is one of the top wood boilers. But if you know, like became apparent to me, you couldn't sustain wood for the remaining years of your life, pellets in 40 lb bags is awesome, inexpensive, and painless. I LOVE not being a slave to the BioMass. Now have the best of both worlds and WAY cheaper, warmer than propane Cheers

 

[pbvermont]

Tennman's post is the answer to the OP's original question. Do not try to adapt a Garn to burn pellets. Pellet boilers are very sophisticated machines (so is a Garn for that matter). The Austrians have figured it out. Pellet boilers are more like oil/gas boilers. They are reliant on the careful metering (feed) of fuel and air during the burn. Yes...the Garn and the pellet boiler both are solid fuel burners that burn wood...but they are VERY different systems. You can't just add a big charge of pellets in a Garn and then let it burn at full tilt--which is how it is meant to burn cord wood. The whole point of pellets as a solid fuel is that they can be delivered, stored, handled and burned almost like a liquid/gas fuel-- I'm talking, in bulk tons--not 40 lb. bags. If you locate a very high quality source of bulk pellets that can be delivered and stored properly, it will be a very reliable and consistently burnable fuel. This is in comparison to the great variability of cordwood w relation to moisture content and quality. Bulk pellets...you never put a finger to. I believe the price of pellets is above the price of #2 fuel oil right now. There's that.

 

[TCaldwell]

While it is doable, it would not be a automatic change over, for that tennman has the model system. If you got too old to handle firewood and didn't want to change the garn out, for under 3k and a few days labor you could be on your way.

 

[velvetfoot]

How about the compressed logs? They arrive on pallets. Still have to load.

 

[S.Whiplash]

i believe the op is talking about a pellet burner, not just burning pellets around cordwood, upon talking to pelltech a burner distributor, this is doable.
The garn burn chamber size lends well for heat transmission and cleaning, just need a dedicated door to interface the pellet burner head, the change required would be matching the draft requirement of the pellet burner through the garn. Most likely requiring a different inducer with less cfm, this should not be difficult, and a tuning of the pellet combustion with a portable fluegas anlyser. The only other issue i see might be very low flue temps, and this depends on burner output and tank temp to be maintained.
I will make a standing offer to test the viability if someone can come up with a pellet burner/controller for a month. I have all the fabrication stuff and testing /tuning equiptment. The burner should have a output of 100kbtu/hr or better and run on 60hz

I'd think the heat-exchanger tubes on a Garn would be too big for this conversion to work effectively. Instead of having 100 lbs. of wood burning all at once a pellet burner is going to be burning a couple of pounds of pellets at a time, it would take forever to heat up the thermal storage in a Garn in this method.

 

[Flathill]

I'd think the heat-exchanger tubes on a Garn would be too big for this conversion to work effectively. Instead of having 100 lbs. of wood burning all at once a pellet burner is going to be burning a couple of pounds of pellets at a time, it would take forever to heat up the thermal storage in a Garn in this method.

 

[Flathill]

Interesting comments about using a pellet burner in the front door of a Garn Boiler. I want hot water storage and be able to burn fire wood and or wood pellets. The wood pellets make it a more automated system. So I'm not sure where to go ? My choices are a Garn Boiler and retrofitting a pellet burner to it and other control items. Or go with a Garn Boiler and a separate wood pellet boiler piped into the Garn water storage system.
I know that burning pellets in the Garn Boiler would be a more time consuming process. Holding the heat in with less wood pellet btu content would most likely require a slower combustion air fan and other control adjustments. It would be a real interesting project !

 

[TCaldwell]

It would be interesting, you know I'm a proponent of this idea. I'd liken it's output towards the end of a batch burn as far as output goes. Silly question, have you talked to Dectra about this.

 

[goosegunner]

Wouldn't it be easier to buy a system that is designed to burn either pellets or wood?

I believe the Effecta boilers can be purchased with a pellet head that is supposedly very simple to switch back and forth.