Garn 2000 for house and shop

hwater85

New Member
Jan 22, 2020
10
Virgilina, Va
I don't own a Garn Unit, but I really like the design. I'm in the beginning stage of building a 1200 gallon system, inspired by the great Gary Switzer. All the steel is on order and a local fab shop is doing the rolling and bulk welding of the tank. I may regret this build in a few months, but I've pulled the trigger. No turning back now.
Nice to know that I can sit the tank on a foam foundation.

Adam
 
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Highbeam

Minister of Fire
Dec 28, 2006
17,043
Mt. Rainier Foothills, WA
I know of two other Garns in our county, one I've seen and one I haven't. You're not that far away, do you have one as well?

Yes, it is sitting on Dow Thermax Polyisocyanurate Insulation which has a compressive strength of 25 psi. The boiler full of water and given the runner area only applies 8.3 psi, so although it seems counter intuitive the foam is more than adequate to support the weight.

Grigg
We sometimes build roads on top of foam now. Then drive 100,000 lb trucks over them. 20 psi is a lot. Usually way stronger than the soil beneath.
 
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hedge wood

Member
Mar 1, 2009
102
Eastern NE
Grigg
Good to see your making some more head way. I run four different systems out of my Garn so it looks like I bought stock in a plumbing wholesale company behind my Garn. It runs into a lot of money plumbing these Garn's up.
 

maple1

Minister of Fire
Sep 15, 2011
10,382
Nova Scotia
Grigg
Good to see your making some more head way. I run four different systems out of my Garn so it looks like I bought stock in a plumbing wholesale company behind my Garn. It runs into a lot of money plumbing these Garn's up.
That goes for any boiler & system. Big time.
 

Grigg

Member
Jan 7, 2015
21
Lexington, VA
It has been a lot of pipe fitting in a small space. The last three days work has kept two guys busy, and they're very efficient workers having probably half a century of experience between them.

Here's a more up to date picture. Still a few connections to be made and a couple valves to install.
 

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salecker

Minister of Fire
Aug 22, 2010
1,009
Northern Canada
It has been a lot of pipe fitting in a small space. The last three days work has kept two guys busy, and they're very efficient workers having probably half a century of experience between them.

Here's a more up to date picture. Still a few connections to be made and a couple valves to install.
You should get a valve on each side of the filter before they finish and fill it with fluid.
 
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hedge wood

Member
Mar 1, 2009
102
Eastern NE
Yes, more iso valves. One on each side of each circ and all other components. Do I see a filter? One on each side of that especially.
I sure like a valve on each side of the pump. Makes changing the pump a lot easier. You want a valve on each side of that filter. I even installed a gauge on each side of my filter so I can see if it is plugging up.
 

Grigg

Member
Jan 7, 2015
21
Lexington, VA
Thanks for the replies.

Yes, we now have valves on each side of the filter.

It is a Tekmar 3 way valve for the radiant floor loop. Tekmar controls, and for the floor outdoor reset. The other zones with duct or fan coils will have ordinary thermostats I think.

Finally ready for the first fill (with the cleaning chemicals) today.
I'll fill through the filter and wire the main circulator pump to run.
Can I start a fire and just plug the blower in to warm the water for better cleaning? Still a little ways off from installing the Garn control box and sensors.

Thanks,
Grigg
 

Grigg

Member
Jan 7, 2015
21
Lexington, VA
First fire went OK but was interesting.
It huffed and puffed some illuminating a few things I didn't understand or didn't think were important.
The door wasn't closing firmly enough, I thought it was reasonable to start with, quickly adjusted by turning it. Figured that out when it started chugging and made a nice show of sparks out from around the door gasket.
That helped reduce the huffing and puffing but you could still fell it mildly surging, kind of like it had a pulse.

The room it is in has two 8'x10' garage door openings without doors in them. I had cut the air inlet hole in the wall 2' or less away and inline with the inlet on the stove but hadn't yet connected it thinking with the hole in the wall and two huge doors open it'd easily get fresh air. Very likely not having the inlet plumed outside the room with the exhaust was the main reason for the chugging as it resolved after sliding the cardboard stovepipe box through the wall as a make shift air inlet duct. It was really quite interesting, you could actually feel the upstairs floor flexing up and down gently to the pulse of the stove, again the room was wide open to the outside.

That sorted out easily enough and no more issues other than the expected condensation from the stove pipe.
Started a second fire this morning and got the tank up to 145 degrees F. Later this afternoon drained the first fill with the precleaner.

Next task is rinsing and cleaning the inside. I hosed it down a few times as it was draining to rinse the rust bubbles off.
Once empty climbed in with garden hose and a rag to wipe and rinse all the little rust spots.

It was pretty challenging to get everything and difficult to drain the last inch and a half or so. I scrubbed and rinsed for an hour tonight. I'll go back in tomorrow morning with a sponge and buckets to mop up the water and rust or sediment.
Is this normally so difficult? The manual says to just spray the interior surfaces and drain then clean whatever remains in the bottom. Spraying wasn't removing the rust bubbles, I had to wipe them before they'd rinse off.

I was prepping it this week to fill it on Monday. I'll be away later this week, need to install the thermometer that comes Friday, and we have to purchase/haul water for the real fill.
Not mentioned in the manual but I'm wondering if I need to fill it promptly or somehow dry it out otherwise I expect it continues to rust over the weekend?
 

TCaldwell

Minister of Fire
Yes, fill as soon as possible to mitigate new rust. I use a shop vac to clean the last bit of water, debris. The inline filter should do the rest, change frequently when the pressure builds due to being plugged during the first few weeks.
 

hedge wood

Member
Mar 1, 2009
102
Eastern NE
After I did my cracked weld rebuild last summer. After running the precleaner in the system and then draining the tank I used a small pressure washer hooked up to my hot water heater to get it good and clean and then used a wet vacuum to get the bottom cleaned up. I filled it right way and warmed it back up and checked for leaks and got the final chemical added and got a pump running.
 

mike van

Feeling the Heat
Apr 24, 2013
361
Kent Ct
Grigg - Seven years ago my new Garn spent a week between cleanout & fresh water, and it did rust inside. A lot. I dealt with that for a long time, finally adding a Garn filter to stop the fine slimy rust from plugging the heat ex. If you can see rust forming inside the tank, I'd wipe it all down, maybe using a few heat lamps? if needed to warm & dry the steel to stop it before it re-rusts. My tank was dirtier, rustier, and more of a problem after the clean out chemical process than before.
 

Grigg

Member
Jan 7, 2015
21
Lexington, VA
Thanks for the replies and input.

I talked to Martin about the post pre-cleaner rust spots being hard to wash off and he said it happens occasionally perhaps as a result of my particular water chemistry but is not a big concern.

A wet shop vac would be handy but I managed with a bucket and some rags, didn't take that long and only about a half a bucket full to mop up.
Didn't have time to get it fully perfectly dried out before leaving town but it was none the worse upon my return.

Monday we had water hauled and that went fine and filled very fast with a 2" hose. Understandably the delivery guy was unwilling to let me fill it through the filter with a garden hose given how long that would take..
Lit a fire Monday night and again Tuesday morning getting it up to 120 *F. By Sunday morning it was down to 70*F
I've had the main circulator pump and the bypass filter pump running the whole time.

Now I have the inlet air pipe, damper, and hood fully installed as well as the exhaust pipe.
Installed all the sensors and mounted the control box this week and had the first fully automated burn yesterday, Sunday, morning.
I added a hour meter for the blower motor to satisfy my curiosity on total run time in the years to come.

This week I hope to insulate and install the remaining 5/8" sheet rock around it. Then run the last bit of conduit on the outside of the enclosure for the sensor wires and permanent power.
Also this week we'll pull the two piping circuits down to the basement of the house and should have the shop floor manifolds connected and heating the floor. Probably get everything wrapped up in time for warm weather.
 

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Grigg

Member
Jan 7, 2015
21
Lexington, VA
We could heat domestic hot water year round, not sure if it's wise to do so?
Where the Garn is will be air conditioned in the summer and if the unavoidable heat loss from Garn and related piping is great enough it'd be better to buy propane for hot water than burn wood and the added electricity/AC load. Haven't tried to put numbers to that to decide.

Another thought is install electric heaters in the Garn and if our solar system over produces in the summer (not sure if it will) then dump the extra into the Garn for DHW. Still the same considerations as above for offsetting heat loss.
 
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Grigg

Member
Jan 7, 2015
21
Lexington, VA
Slowly making progress.
The Garn is insulated mostly, need a few more bags of rock wool. Drywall to follow.

Both pairs of pipes now pulled to the basement, nearly 50' run. Decided to put both supply lines insulated together and same with return lines. Each pair in one piece of 1/2" thick black foam pipe insulation and pulled through 4" PVC.

The floor is connected with operable thermostat and heating, no troubles so far. Waiting on the Tekmar controller for that zone. For now set the mixing valve manually and not firing the stove over 120*.

The rest of the zones will probably take a while to get connected. Still not sure if radiant, radiators, or baseboards in the house. Comparing options and prices.
 

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TCaldwell

Minister of Fire
Nice and neat work, one thing I have done for a controller mount is to use a small vesa tv mount . I find it keeps the controller cooler and allows for friendlier viewing angle.
 

Grigg

Member
Jan 7, 2015
21
Lexington, VA
Thanks, I am also quite pleased with their piping abilities, attention to detail, and willingness to modify and improve if they (or sometimes I) think of a better design option.

The TV mount sounds and looks like a good idea. I'll stick with what I have for now, it is easy enough to view as the wall it is beside is right at a doorway you can stand in. Otherwise adjusting the angle would be desirable.

Nearly done insulating the boiler all except for the front and part of the back. Pictures attached of that in progress before getting 3" between the studs and 6" between floor joist. Nominally 12" rock wool top, 9" sides, more in the corners, and 8" polyiso underneath. Front only fits 3.5" and not sure yet on the back but 6" or 8" minimum.

Some thoughts about the install thus far.
8" of foam riser underneath is a good height for me being 6' tall, and a couple inches higher might be even more comfortable for loading wood in it.
It's in a room 18' deep/wide from front to back of the boiler, 20' would be perfect. We designed the building to the space available and 18' was all we had. To start with the Garn was drawn 90 degrees to how it sits now but that idea didn't fly after evaluating exhaust options. Cross ways in the room is much better use of the space except it is very cramped behind the Garn. Room is right at 18' wall to wall less 8" at the stem wall that is about 30" tall. We pushed the Garn back as far as reasonably possible still leaving room to sort of get behind it but it's really cramped, can't do much if you do fit back there even if the stem wall weren't in part of that space. I'd recommend 2' walking and pipe room behind it not counting the desired insulation and drywall on the back. Because of the tight space I'm going to end up with it all closed in behind but with removable side access panels, no walking room.

Grigg
 

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eauzonedan

Member
Jan 21, 2011
95
Bayfield Co. Wi
2’ is about min for my large girth in back. 7 ‘ out front with a couple building door swings, an old farm scale and a wood wagon was about right also. 5 ‘ would be getting a bit weak but doable. It was my first shot with steel studs and went thru lots of band aids.

I used white gloss hard board on sides with thin cement board on the fire breathing end - all attached with self tapping screws. Worked out well! EABC5477-72CD-4ED7-9CB7-9A690B47D083.jpeg

Great looking project
Dan
 

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eauzonedan

Member
Jan 21, 2011
95
Bayfield Co. Wi
Sorry bout extra baggage.... bad phone!! Bad bad phone! ......It listens about as well as the Labs. Dan
 

hedge wood

Member
Mar 1, 2009
102
Eastern NE
Dan
Looks like you went with a stainless filter housing. That is what I installed when I did my repair last year. I was worried the plastic might not stand up. How often have you been changing your filter?
 

eauzonedan

Member
Jan 21, 2011
95
Bayfield Co. Wi
I’ve Got some crazy form of iron in my well water. I worked with Mike at Precision and we confirmed his chemicals will combine with it and create a cloudy flock than can be picked off by the filter. It’s critical to pull it out as a flock as if it settles out - it turns to a sludge that will prevent Mikes cocktail from protecting the steel. After a fresh well water fill it will load a filter a day for a couple weeks. Once it’s out of the water I go months without any rise in back pressure in the filter loop that signals filter swaps. I’m now running the new manhole cover that solved almost all evaporation and thus my crappy well water additions. Last spring I topped up with maybe 30 gallons of water and a quart of Mikes secret recipe. Maybe burned a couple filters to get back to gin clear. Last filter swap was last sept and still shows about 4 1/2 psi back pressure which is pretty clean. ... sorry bout the long version but thought it important to understand the full picture. I also have a couple hose bibs in the pump circuit to allow a hose run with a PEX wand into the full tank to rouse the knooks and crannies and/or vacuum the pool. A clean tank is a happy one!!
Dan