Garn Owners - please give me some advice

[maple1]

That won't work very good when just heating DHW from storage (or the Garn between firings) in the summer though will it?

 

[sjfrench]

One extremely simple way to do domestic water is to tee a flat plate HX into the cold water line entering the heater, IF you can tap into a loop in your system that is constantly circulating.

Tee out of the incoming cold line, into the HX then back out of the HX and into the HWH. Leave a bypass in place so you can isolate the HX in the summer if not using the wood boiler.
Incoming cold water is now heated from ground water temp up to 110-120*+ depending on the size of heat exchanger you are using. Your water heater now has to do nothing but maintain temp of the tank so 90% of the load is gone. No extra pumps, no controls, no wiring, just pre-warmed water going into the tank.

We used a 10 plate on a job like that a couple weeks ago and the incoming water was 140* with a boiler water temp of 160*. It would maintain that with 2 faucets running but when we turned on the tub + the kitchen and bath faucets the water temp fell to about 120*. Still not bad for such a simple install. About $35 in fittings/ball valves + the cost of the 10 plate which was around $190 or so.
Going to an aquastat controlled system and a pair of pumps to circulate both sides of the HX will run around $4-500 + the HX.

That is very interesting idea! I've got a plumber who is going to do the DHW hook up for me. Considering that I'm having all of my loops on a continuous loop, that should be a real possiblity. So two questions:
1. Where do if find an example of the plate you used?
2. I'd still like more info on that Garn sweater you mentioned in an earlier post. How do I get pricing and ordering info?

 

[heaterman]

The HX we used is just a standard flat plate type heat exchanger 5" x12" with 10 plates or sections. It has 1" pipe threads on all 4 corners, one side being for the domestic and one side being for boiler water.
Use a greater number of plates for less flow resistance on the boiler side of things and more heat transfer if you anticipate higer GPM draws from the water heater.

A kit shipped to your location would be $1,355 for a model 2000. It consists of ridgid fiberglass board for the front and back and fiberglass blanket for the sides. The front piece is pre cut to fit around the door/air collar and the draft motor and is covered with a heavy aluminum scrim to resist punctures a little better than the reinforced poly coating used on the sides and back.
The back piece is also precut for the openings back there. It comes with both aluminum seam tape for the front and a large roll of reinforced poly tape for the back and sides. Stick on "nails" are used to hold the blanket tight to the bottom of the Garn on the sides.
It is made to offer decent insulating qualities and be very easy to install. A couple guys can usually do it in less than an hour.
It also allows 360* access around the Garn for ease of service and future maintenance.

 

[sjfrench]

The HX we used is just a standard flat plate type heat exchanger 5" x12" with 10 plates or sections. It has 1" pipe threads on all 4 corners, one side being for the domestic and one side being for boiler water.
Use a greater number of plates for less flow resistance on the boiler side of things and more heat transfer if you anticipate higer GPM draws from the water heater.

A kit shipped to your location would be $1,355 for a model 2000. It consists of ridgid fiberglass board for the front and back and fiberglass blanket for the sides. The front piece is pre cut to fit around the door/air collar and the draft motor and is covered with a heavy aluminum scrim to resist punctures a little better than the reinforced poly coating used on the sides and back.
The back piece is also precut for the openings back there. It comes with both aluminum seam tape for the front and a large roll of reinforced poly tape for the back and sides. Stick on "nails" are used to hold the blanket tight to the bottom of the Garn on the sides.
It is made to offer decent insulating qualities and be very easy to install. A couple guys can usually do it in less than an hour.
It also allows 360* access around the Garn for ease of service and future maintenance.

A kit shipped to your location would be $1,355 for a model 2000.

How do I place an order, and I'd like to ask some details on the R-value of the product. Do I contact Fabrication Solutions?

 

[heaterman]

Dial BR-549.....


kidding..

You would simply give me the word and I'll get in touch with you personally to hash out the details.

The R-values are in the 15 range for the whole kit. Not as high as you can achieve building an enclosure from scratch but the kits have proven adequate to say the least. The blanket fiberglass used in the kit is about 4 times the density of typical stock used to insulate a house. They are pretty air tight once the seams are sealed.

 

[woodsmaster]

We are using a sidearm exchanger. Not ideal, but it will work. I wanted new DHW tanks with the built in coils...but alas...too expensive.

If you plan to heat your DHW from storage in the non-heating seaon, you'll likely be disappointed with the sidearm.

Why would he be disappointed ? I wouldn't say it is the best option but why the disappointment ? I have a side arm and heat my water all summer. I can usually go 4 to 7 days between fires with 1000 gallon storage depending on demand.

 

[maple1]

Why would he be disappointed ? I wouldn't say it is the best option but why the disappointment ? I have a side arm and heat my water all summer. I can usually go 4 to 7 days between fires with 1000 gallon storage depending on demand.

I think I explained my reasons in post #24 - just one point of view.

Do you pump the DHW side of your exhanger? Do you measure all the temps in & out of it? Just curious on your exact setup & what you are seeing for approach temps.

 

[woodsmaster]

I think I explained my reasons in post #24 - just one point of view.

Do you pump the DHW side of your exhanger? Do you measure all the temps in & out of it? Just curious on your exact setup & what you are seeing for approach temps.

I didn't read the other post. I agree that it does take longer to recover when temps drop below 150. Mine is also convection. If you pump the domestic side it will increase transfer and recovery time a lot so I've heard. My ideal setup would be a flat plate on demand type. I don't use as much hot water as I did. Got rid of the wife and my step daughter is only here once in a while so the sidearm works great for me, 2 kids and girl friend. New girl friend don't stay in the shower for a half hour like the wife did. lol