Garn owners operation tips

[Birdman 22]

Just finished installing my GARN 2000. I have 26 burn days on it and it has been fantastic. Did the complete installation my self for excavation, plumbiing, electrical and building. Learned some interestiong things. I am space heating (two homes 4150 sq.ft.) of living space and potable water for both homes with 10 residents. So far the mose wood i have burned in 1 week is 30 sq. ft. (just less that a full face cord). If anyone has any tips on operation i would appriciate the feedback. Thanks

 

[TCaldwell]

this is my 3rd year with a model 1900, burn all year, heat,dhw , hot tub and 20,000 gal swimming pool. first, obviously good dry wood is important, without that you will not reach high enough temps in the secondary reaction chamber, if you elevate the wood off the firebrick, about a inch allowing airflow underneath you will reduce the time it takes for the secondary reburn to start, ie less smoke at startup. at a cold start i fill the firebox about 1/2 full, at 45 minutes i reload sometimes full and push the wood towards the secondary burn chamber, this helps to aleviate puffing. about puffing, it will happen if there is too many combustibles for the given ammt of air, pack small dry wood tightly to reduce sqft area of burnables, not so important with larger splits. sometimes opening the loading door to the safety on the latch adding combustion air for a few minutes will help if the puffing is violent.good luck and let me know what works best for you. tom

 

[brad068]

this is my 3rd year with a model 1900, burn all year, heat,dhw , hot tub and 20,000 gal swimming pool. first, obviously good dry wood is important, without that you will not reach high enough temps in the secondary reaction chamber, if you elevate the wood off the firebrick, about a inch allowing airflow underneath you will reduce the time it takes for the secondary reburn to start, ie less smoke at startup. at a cold start i fill the firebox about 1/2 full, at 45 minutes i reload sometimes full and push the wood towards the secondary burn chamber, this helps to aleviate puffing. about puffing, it will happen if there is too many combustibles for the given ammt of air, pack small dry wood tightly to reduce sqft area of burnables, not so important with larger splits. sometimes opening the loading door to the safety on the latch adding combustion air for a few minutes will help if the puffing is violent.good luck and let me know what works best for you. tom

Hey Tom,

How did you hook up your unit for the supply return positions?

 

[Tattooz]

Could you post some photos of your plumbing set up... Pumps and all... Please, Thanks!

 

[TCaldwell]

birdman, one last thing, as you know creasote is a thing of the past with a garn, but flyash does coat the flue/hx tubes, reducing the heat absorbsion from the hx tubes to the surrounding water, thus lower effiency. i brush the straight tubes with a knotted wire wheel and drill with several drill bit extenders,and the rounded bends with a conventional brush and fiberglass extenders., about once a month.
Brad, i went by the manual that came with my unit, supply from the bottom, return to top, i have been told garn has gone to the opposite now?I installed a temp sensor on the bottom supply line and basically call that my supply temp to hx. the supplied thermometer installed in the boiler bung reads about 8-12 deg higher.
Tattooz when i get some time i will post pics, call me if you like

 

[Tattooz]

Thanks TC I am right in the middle of the plumbing part, and am looking for all the input I can get. Funny how they change the supply and return.... wonder what the reasoning behind that is.

 

[brad068]

Thanks TC I am right in the middle of the plumbing part, and am looking for all the input I can get. Funny how they change the supply and return.... wonder what the reasoning behind that is.

Tat, is that what your manual says, supply on top return on bottom? I may want to change my setup if that is the case.

 

[Tattooz]

Yup ...

 

[Tattooz]

 

[Tattooz]

 

[brad068]

Well I'll be damned! Out of all the variables and built in adjustment I made to my boiler I didn't make the plumbing an easy switch! Ahhhh.. it wouldn't be to bad.

 

[Tattooz]

Speak with TCaldwell before doing anything he told me Garn may have made some changes to the units. and thus the changes to the plumbing.......

 

[Sawyer]

if you elevate the wood off the firebrick, about a inch allowing airflow underneath you will reduce the time it takes for the secondary reburn to start, ie less smoke at startup.

Tom, what do you use to elevate the wood? I am assuming you put a few pieces of wood crosswise in the chamber and then stack on top of that.

 

[Sawyer]

Speak with TCaldwell before doing anything he told me Garn may have made some changes to the units. and thus the changes to the plumbing.......

I have the Garn installation Manual-Rev6- 0908 and it also shows the supply pumping from the top.

 

[Birdman 22]

Tom, thanks for the advice, I have one other question maybe you could help with. I fire the unit pretty much the same way you do, a smaller load to start then a larger load to finish. My question is what kind of exhuast temperatures are you running, on a partial load I get arount 350 degrees on a full load I have gotten up to 550 degrees, hope thats not to hot. This is a picture of my piping, Supply on the top return on the bottom.

 

[Sawyer]

Tom, thanks for the advice, I have one other question maybe you could help with. I fire the unit pretty much the same way you do, a smaller load to start then a larger load to finish. My question is what kind of exhuast temperatures are you running, on a partial load I get arount 350 degrees on a full load I have gotten up to 550 degrees, hope thats not to hot. This is a picture of my piping, Supply on the top return on the bottom.

Question Birdman, why did you choose not to plumb your Garn Primary/Secondary? I am asking before I do my install, I was planning on Primary/Secondary.

 

[Birdman 22]

Sawyer, After speaking with GARN and doing my own research there were a few reasons.
1) Less moving parts, only need 1 pump/1 controller instead of two with the close loop.
2) People that I had spoken to that had piped there hx into the return line were having great results, and at this time I feel the same way. Very simple installation and it works great.
3) When I spoke to GARN about the installation they said the return line installation was fine and that there is no reason to do a close loop installation.

I have both the homes that I feed from my GARN set up the same way, both have been working great. Its a very simple setup but that's all I need. I know when I was installing mine I got way to deep into the installation and was looking at all sorts of things. After I went back to the basics it all fell into place and works very well. I do know this I live in the Adirondack's of NY and had a hard time finding any help. If you look in your GARN installation manual there is a very basic setup shown, I believe that's all you need. I have the supply and return header on my unit, both houses are feed by Wilo 3 speed pumps, through a check valve to 1 1/4' pex 85 feet to one house, 200 feet to the other, both go through 5x12x30 flat plat exchangers and back to the GARN. The Feed pumps ard controlled from a dry contact on the Honeywell 845 relays over to there own 845 relay. Very simple, but works great. Hope this helps

 

[TCaldwell]

birdman and sawyer, i have seen temps at the last pass out exceed 600degf. typically they range from 350/450degf. the 600 was on a load of biobricks, the hottest stuff i have burned hands down. my flue temps are monitored with a type k thermocouple located in the first duravent section attached to the garn, basically at the back of the garn. i have a turbulator made by fuel effiency llc 1 800 448 9794, cost $180.00. it is 9 ft long and slips into the last pass flue behind the last cleanout plug, the flue temps now max out about 330degf but average below 300.
to elevate the wood off the firebrick i use a couple of black iron nipples, due to the heat they are short lived, will replace with something more tolerant

 

[Sawyer]

Thanks Tom, but now I have to read about tabulators! ;-)