Garn video

[muncybob]

I viewed the video of an older Garn unit on their web site today. Very interesting! I did not realize how huge these units are due mainly I suspect to their onboard storage? Due to their size I don't think I will be in the market for one although I wish i could make one work for me. I took partuclar note that this video showed a horizontal flue/exhaust out the side of the building rather than a vertical exhaust(normal chimney). How can the Garn accomplish this when all other applications I have seen require your standard chimney configuration?

 

[heaterman]

I viewed the video of an older Garn unit on their web site today. Very interesting! I did not realize how huge these units are due mainly I suspect to their onboard storage? Due to their size I don't think I will be in the market for one although I wish i could make one work for me. I took partuclar note that this video showed a horizontal flue/exhaust out the side of the building rather than a vertical exhaust(normal chimney). How can the Garn accomplish this when all other applications I have seen require your standard chimney configuration?

Garn uses a combustion blower and HX design unlike anything else on the market. The firebox and heat exchanger firetubes are horizontal in the unit with 5 full passes running from front to back. The end of the 4th pass is at the front of the unit and that's where the combustion blower is mounted. All parts of the firebox and heat exchanger are operating under negative pressure up to that point which is why there is no smoke when the door is opened. The downstream side of the blower (the 5th HX pass) is under pretty substantial positive pressure from the blower so no draft or vertical flue is needed. The flue gases are forced out instead of relying on natural draft. You can also vent the Garn vertically if you chose to do so.

Most other types, with the exception of the better grade European units, are positive pressure all the way through the firebox and heat exchanger. They will smoke and vent exhaust gases into the room when the door is opened regardless of whether the fan is running or not.

 

[muncybob]

Interesting! Seems this would be an ideal set up for a boiler inside living space such as my basement. Unfortunatley I think the size of the Garn will work against me. I really like the idea of a boiler in my basement so facing the weather is limited to once per week when I am gathering enough wood to get me through 7 days or so of burning but I'm very concerned over the amount of smoke and exhaust in general that will come into my basement every time the door is opened. I don't have a problem with floor debris that can be swept up but air pollution is something that bothers me. Am I being overly concerned about this?

 

[chrisfallis]

I had a Tarm gasifier in my basement and there was a little bit of smoke roll out when refueling, but it got less and less as I learned to fire the boiler better. The biggest issue was the very fine dust that was stirred up when I cleared out ashes. I think this would be taken care of with a vacuum cleaner that vented outside. That being said, I am considering a Garn boiler for my garage, and am concerned about smoke and dust for my new application. Whenever I look at boilers that have been in service a while, I always look at the smoke stains above the loading door. The smoke dragons (OWBs) are always black and nasty above their doors. The 20+ year old Gran in the movie has a slight smoke stain. The two year old Garn I saw in action last fall had a small stain above its door as well. This Garn was installed in a shipping container outside a school and we had to open the outside door of the container after reloading due to a smoke haze inside. I have used regular fireplaces for 40+ years and I would have to say that boilers, even those with forced draft systems, can smoke more than a regular fireplace ever would. I believe that the makers of the Woodgun recommend an outside vented smoke hood, even though it has a draft fan installed between the firebox and the chimney. A beast in your basement (or garage) is going to puff once in a while. Open your doors, windows, install a smoke hood or accept it as a side effect that you can deal with. Maybe that is why these things are usually installed in sheds/outbuildings where a little smoke or dust won't matter.