New Garn installaton -- Need your advice

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.
McKraut

McKraut

Feeling the Heat
Sep 1, 2011
349
South Central PA
Hello to everyone. I have enjoyed reading all about your experiences with boilers. Because of your wealth of experience, I would like to ask you for some advice.

I currently live in south central PA, in a 100+ year old farmhouse with some insulation (I know it’s there because I see it blow across the floor when it is windy). I have been heating the last 15 years with a Tarm Excel 2000 with oil backup. The house is roughly 3600 sq.ft. and I burn about 5 to 6 cords of hardwood, along with 100-200 gallons of oil per year (If I use only oil, I burn about 50 to 60 gallons a week). I have baseboard heat, set at 68 degrees, on all four floors and we also use the system to heat our DHW . The Tarm has been a great setup, but after 15 years the secondary combustion chamber is starting to show its age, my wife is sick of the dust in the house and I am tired of loading wood in the basement (especially since the kids are away at school). I was considering going with the GARN, Frohling, or the E-Classic 2300, but after reading countless threads, and doing a lot of research, I am going with the GARN.

I am planning on putting the GARN in a woodshed that I am building this fall. I am timber framing an 18 X 30’ woodshed about 100’ from the house. I figure with this size I can easily store enough wood, have room for the boiler, and still have room to move around. I would like to keep the Tarm in my basement as the backup oil burning boiler, and pipe the GARN into the existing setup.

Would you have any specific recommendations for my situation? I have already made a mental plan for how I would like to set this up, but before I put it down on paper, I would love to hear your thoughts.

Any advice, tips, or warnings you can give me would be greatly appreciated.

Thank you....Bob
 
My initial thought is why so far away from the house with your Garn Barn? Is there any chance you could "add on" and have it adjacent to the house?

Aside from that I'd say you've made a great choice with the Garn. If I had the room I would have purchased a Garn myself. I suggest you draw up a piping diagram with as much detail as you can come up with and post it on this site. People here will be more than glad to review it. That's a good first step.
 
There is only one flat section on our property, close to the house, where we can put it. I am currently reading/studying Siegenthaler's book on hydronic heating, so I haven't developed any schematics for the plumbing yet. My initial concern, besides choosing the boiler, was basic preparations so I can get started on the woodshed (i.e. run water and electric) now and finalize plans later for the actual boiler installation later.

Thanks,

Bob
 
Sounds like the standard setup. I installed my Garn last year. I have a flat plate HX about 5' from the Garn and I plumbed the microflex underground to my oil boiler were I tied to into my primary loop. So, I have the Garn injecting water into the primary loop from a secondary loop....well, the HX actually...the Garn water leaves the Garn only to travel to the HX.

Very simple and straight forward. Sounds like you can do the same type of thing and bring the hot water into the primary loop you already have, so just add the Garn as a secondary.

You may also find heatinghelp.com very useful....The Wall. Dan Holohan over there has a couple of "little books" you can read in an hour or two and really drive home primary/secondary, pumping away, basic boiler plumbing.

As for your tag line, let me know if you figure out how to get both of your kids to want to learn. :)
 
Thank you for the information. I will check out the Heating Help tonight. Can you tell me what size pipe you ran? I was going to run 1&1/4 inch in either Microflex or Thermopex.

I could have bought 3 GARNs with the money I spent "educating" my kids. I guess I am the one that really got the education.
 
LOL....I have three in 12, 11, 9th grade....my time is coming. I ran 1.25" microflex as well and 1.25" copper, with 1.5" or 2" black iron right near the Garn itself. Do you have a heat load and know more or less how much you need to move? 1.25" is fine in typical applications....1" is a bit small.
 
Here's the working diagram I had for my near garn plumbing....it is pretty easy once you just get going. Don't believe the measurements exactly...this was my plan. Seems to work very well. Having Y-strainers around your HX is a good idea. Make sure you have isolation valves, drains, etc. where ever you may wish you did.
 

Attachments

  • Untitled.jpg
    Untitled.jpg
    99.6 KB · Views: 625
I appreciate the diagram. I will keep this in mind for the install. I printed it out and will keep it in my notebook. There is so much to learn!!
 
McKraut said:
I appreciate the diagram. I will keep this in mind for the install. I printed it out and will keep it in my notebook. There is so much to learn!!
Click to expand...

Bob - Knowing the peak heat load will help you determine the correct size piping, as well as other key factors. I heat my 2800sf, 200 year old farm house with a WHS2000, and I used 1.25" piping for the run of about 120' (only about 60' of which is underground). I suspect that unless you are over 100k btuh max heat loss, the 1.25 should be fine.

Feel free to PM me with any questions.
 
Just out of curiosity. Do you lose any efficiency in the transfer through the heat exchanger? I always wondered that and never found out. I considered a Garn but wanted my boiler in my basement. Garn was to big to get down in there. Man they are big.

But I like the pressurized system that I have too. Good luck with the Garn, I hear they are very nice. Most of the boilers everyone has on the site sound like they are very nice. I am so friggen excited to have my system on line and be heating everything with wood.
 
I oversized my HX becuase I wanted to get the temp as close to the Garn water as possible. That way I can use my Garn water to heat radiant all the way down to 120-130 or so. When I looked last year, the temps were within 2 or 3 degrees of each other going in/coming out of the HX. So, in theory, if the Garn water is 125, I should be able to get 120 into the house.
 
A plate hx might normally be expected to provide a 10F approach temperature, that is 180F delivered by the boiler = 170F delivered by the hx. The hx can be over-sized to achieve a closer approach temperature. Sizing a plate hx is a little complicated, as sizing is closely related to flow through both sides of the hx, pressure drop (pump head) on both sides of the hx, and then sizing of the entire system with circulator to provide the required flow based on total system pump head.

I have seen advertising on plate hx's showing very high btuh performance but in doing so do not state the required flow rates to achieve this performance, and the required flow rates are in the 20+ gpm rate. This is much higher than most home boiler applications (20 gpm = 200,000 btuh at delta-T = 20), and if your system + hx head when matched with your circulator will not provide the required flow rate to obtain the advertised btuh performance, you may be very disappointed.
 
Jim K in PA said:
McKraut said:
I appreciate the diagram. I will keep this in mind for the install. I printed it out and will keep it in my notebook. There is so much to learn!!
Click to expand...

Bob - Knowing the peak heat load will help you determine the correct size piping, as well as other key factors. I heat my 2800sf, 200 year old farm house with a WHS2000, and I used 1.25" piping for the run of about 120' (only about 60' of which is underground). I suspect that unless you are over 100k btuh max heat loss, the 1.25 should be fine.

Feel free to PM me with any questions.
Click to expand...

Jim,

What brand PEX did you run underground?
 
Gasifier said:
Just out of curiosity. Do you lose any efficiency in the transfer through the heat exchanger? I always wondered that and never found out. I considered a Garn but wanted my boiler in my basement. Garn was to big to get down in there. Man they are big.

But I like the pressurized system that I have too. Good luck with the Garn, I hear they are very nice. Most of the boilers everyone has on the site sound like they are very nice. I am so friggen excited to have my system on line and be heating everything with wood.
Click to expand...

Technically speaking there is no efficiency loss in a heat exchanger. Any heat (temperature differential) not transferred from side A to side B is simply returned to the original heat source. The only btu's one would actually lose are what would be lost through radiant heat transfer and convection from the surface of the HX itself. Obviously this can be eliminated by insulating the HX.
One could also split hairs and add the wattage consumed by the second circ sometimes required with the use of any type of heat exchanger. For most residential applications this can be largely ignored because of the efficiency of a properly sized modern circulator.
 
In the ideal world the HX is designed and sized to accept the btu's from the boiler and deliver those btu's to the system. Design and sizing is critical here. While there is no technical efficiency loss, there usually is temperature drop between the high temp provided by the boiler and a lower temp provided by the HX. In many cases this is not very important, but if your system needs high temperature water (170F for example), you need to design and size the HX and the plumbing system to accomplish this, and this is an easy place to make mistakes.

For example, if the boiler can provide 185F water to the HX but the HX can only provide 175F water to the system, then the boiler will need to fire nearly at maximum output continuously to meet demand. And if you have storage, you only may have 5-10 delta-T of usable btu's stored, and it will take a very large amount of storage to provide much buffer space or downtime for the boiler. If the HX can provide 180F water in the same example, then you nearly have doubled the usable capacity of the buffer/storage.

All of this starts to bring into focus the importance of designing a low temperature radiant system for new installations, and the difficulty and challenges of meeting heating needs in a high temperature system.
 
Status
Not open for further replies.

Similar threads

K
Help! Need replacement system for my Newmac oil/wood combination furnace
Replies
3
Views
2K
The Boiler Room - Wood Boilers and Furnaces
brenndatomu
brenndatomu
bigealta
Oil fired Old coal burning boiler replacement options?
Replies
8
Views
599
The Boiler Room - Wood Boilers and Furnaces
bigealta
bigealta
H
So when is enough , enough
Replies
12
Views
1K
The Boiler Room - Wood Boilers and Furnaces
sloeffle
sloeffle
P
Cranking through the wood
Replies
2
Views
842
The Boiler Room - Wood Boilers and Furnaces
hedge wood
H
P
Dodging a bullet with my heating system
Replies
0
Views
944
The Boiler Room - Wood Boilers and Furnaces
peakbagger
P
Top Bottom
Back