Post in 'The Boiler Room - Wood Boilers and Furnaces' started by Como, Jan 5, 2012.
50 cords a year, WOW hope there's warranty on the door hinges, cuz thats alot of wood.
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Two is prettier than one. Love it...keep the pictures coming.
Como-estas and Como-tose
So most of the rear plumbing has been done. Snow tonight, Wednesday and Thursday looking good.
You may be wondering what happened to the white stuff, we had nearly 2 weeks of violent winds. They closed US285 for most of yesterday.
The panels for the structure arrived last Wednesday whilst my original idea was to off load them onto the slab, the wind suggested otherwise.
I am going to wrap them initially with Roxul, then if needed will blow in insulation to fill the area leaving access for the pumps.
Looks really good David. good job !
Something about a pair that is really impressive! Looking forward to the next update.
Well we have hit a glitch, delayed us a few days. Plus the wind last week kept blowing the plumbers torch out. We are still unseasonally warm, have not been below 0F for a few weeks.
One thing I did not know, never seen it mentioned here or in the documentation, and which I will pass on is that when you have more than one Garn they should be operated together. My original plan was to operate both in Winter and one or the other in Summer.
Also you will see that each Garn had its own Pump, there must be one pump for all the Boilers.
Hopefully this will help anybody else considering a similar set up.
Wouldn't that just depend on how they are plumbed? So if you plumbed them both separately as a secondary supply into a primary loop, couldn't you then feed the primary either from Bert, or Ernie, or both? I don't see why you have to burn them both all the time....why would they know the other is present?
As for names, do you have two dominate peaks visible from your location? Everest and K2? And yes, I know you can't see them.
Why is that David? I've seen and read about multiple boiler staging but these were standard boilers without storage. Each boiler was plumbed in parallel into a large header loop (boiler loop) with each boiler having its own pump. The primary loop was hydraulically separated from the boiler loop either with closely spaced 'T' or hydraulic separator, as was the secondary loop(s). Not quite understanding why you couldn't do this. You would have to wait until say Garn2 was up to temp to have any benefit of adding BTU output to the boiler loop but that seems doable.
Well the guy who designed the system, all now operational ex Garn's, is now retired but has done thousands of systems. But not Garn's.
The info came from the top at Dectra.
Apparently with Garn's that is just the way it is, obviously with other Boilers, like my Triangle Tube, cascading systems are normal.
Anyway I had to get the W2's out and I still have year end accounts etc etc, so I will get it done the recommended way. I know we will get hit with bad weather soon.
Would love to learn the details why staging or cascading is not possible with Garns.
Would like to know the reason why they cannot be operated separately. I'm aware of a Garn WHS3200 and a Wood Gun E500 both plumbed into a primary loop, each can be operated separately or both together. Garn raised no issue with this installation. The primary loop also has plumbed into it a 4000 gallon pressurized storage tank which operates as a hydraulic separator. Since the system is pressurized, the Garn connects via a plate hx.
One beauty of this system is that, in effect, 7200 gallons of storage are available, as the Garn or the Wood Gun operating separately or both together have available total system storage.
I think in the particular comparison my Triangle Tube is in a similar position to the Wood Gun.
Except my storage is less than 200 gallons.
I'd send one back and just hook up 2000 Gal storage and never look back. i think you've been sucked in to GARNAMONIOUS. MHO.
I think you will find after reading some of David's posts that he did his research, established his loads, weighed his options, investigated boiler models that worked for his situation & then made his choice.
Far from being sucked in as you put it.
David: as far as I can tell from your post & this thread there is no reason that one could not run those 2 boilers however you choose.
One at a time, both at once, alternating, whatever you want.
The only restriction would be how it's plumbed & pumped.
Unless of course the is some funky monkey regulation in your state preventing that?
Again, wide open to being corrected on that.
David says that the info that they cannot be run together --
In my experience if Dectra says something and if an owner does something contrary, then Dectra may take the position that the warranty is void.
If it was me lecturing a class on best design practice with equipment that has wildly different operating potential based on load size and quality. Then I would instruct that for that reason it wouldn't shouldn't be connected like a tandem gas boilers. [like in the picture] That the proper way would be let each unit operate independent as possible and then contribute to the system. In this case make each boiler a secondary contributor to the primary loop around the HX. Each heat source should not be effected by the other, projects in the past have connected, geothermal, gas and wood all to the same system.
It would be interesting to know exactly what the issue they are seeing is, though.
These are the two options
I don't see it but I'm sure that you can have shutoff valves so you can shut one or the other down and just run one. You would want to be able to balance them out also. That setup would save pumps and other plumbing.
I would have to agree with leaddog on this +1.
We re plumbed it today, I have some weather coming in so have prep'd enogh wood for the stoves for a week.
Put some extra valves in, just in case.
Glad to see you are making progress David. I am sure you are very anxious to fire up efficiently!
I am thinking the Garn people might have issues with using shut off valves to isolate one of two boilers, as they could see potential for someone to light a fire and forget to open valves - which would be a bad thing. Just a thought.
^ That wouldn't really be an issue. It is impossible to "overheat" a Garn and a full fire with no circulation is no cause for alarm. The worst case scenario would be stoking one up when the tank is already at 190-200 and literally bringing all the water to full boil. At that point one would have a neighborhood sized sauna stove going in the building but nothing more.
Well in that case, I'm more curious as to why they rule out running one at a time in a dual install.
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