What are we trying to do here?

[sixroses]

Hello, my name is Steve, I live in Wasilla, Alaska. Tonight it's cold, somewhere around -6. :bug: I have been burnig a GW 100 for almost 2 years. There is a learning curve and I am a slow learner it apears.
I got the stove in april of 06 and proceded to "plumb it in". I had plenty of boil overs with the 3/4 in pex and tiny expansion tank that comes with the unit.
Year 2 I replaced the 3/4 with 1 " and better insulation. Installed 300 gallon tank, have had fair success. Heating bills went from $180 a month to $35 month, natural gas, cooking, laundry, DMH. Will use nearly 15 cord of birch/popal this season.
Obviously I would like to decrease my wood usage. How do I properly plumb my heat tank? I am prepared to build a 750 gallon tank and would like input about return and feedlines, temperature monituring, etc..
As of today I have no refractorary cracks, but have had pipes hot enough to melt foam insulation, soften solder joints, and inflect 2nd degree burns. :-S
Where do I find figures for heat loss in a home, gallons per square foot of storage, BTU per gallon, etc..
The years of knowledge that are present on this forum will certainly aid in my quest for perfection which is what we are all seeking!
-Steve.

 

[webbie]

Others can probably help with some of your questions......but I would never use pex anywhere near a wood boiler. In fact, given a situation like your, you might consider steel piping. If you have blown solder joints, you can definitely get higher temp solders, although obviously the boiler should not even be getting that hot.

Do you know how much water the boiler itself holds? Also, I know these use a plate heat exchanger, but why? Is the water in the boiler NOT under pressure? Or is that HE just for DHW?

Looks like I'm asking more questions than I am answering! I know this much - that storage must be matched to the boiler size. Nofossil and others can probably help you with that, but one guideline is that TARM suggests tanks of 400 to 600 gallons for their 100K BTU models, so you are probably in the right ball park.

Flow (speed of the pipe and pipe size) and control are important in charging tanks, so hopefully some of the other more knowledgeable folks here will chime in on that.

Other than that, I would suggest moving to warmer climes!

 

[sixroses]

The GW only holds 10 gallons +-. I have a flat plate HX connected to the boiler, flowing to a side arm HX back to stove. Hot water from the stove flows to top of heat tank, water from bottom of tank flows to my house.
Maybe if I try putting input line to tank closer to bottom of tank I would get higher temps to the house.
The PEX piping is only the 60' between garage and house. All other connections are copper. I did use a shark bite connection that melted at one time.:shut: Thanks for the comment-
Steve

 

[Nofossil]

I'm not familiar with your specific boiler, but it sounds like you don't have enough flow in one loop or the other, or your HX is too small. Would it be possible to sketch a plumbing diagram, scan or tak a picture, and post it? That would help those of us who have a hard time visualizing. Model numbers for the pumps would help as well.

A tool that's helpful for troubleshooting these things is a non-contact infrared thermometer. Sears and HF sell them - they allow you to get instant temperature readings. There are a few threads that discuss them.

 

[Bob Rohr]

My first question would be how big of a heating load do you have? An accurate, up to date heat load calc would be the best place to start.

Second problem I see over and over is the underground pipe insulation detail. It needs to be at least r-10 and WATERPROOFED. I'm surprised how many dealers and manufacturers still sell foam blocks to put around the pipe. Cheap still trumps common sense in underground insulation for many salesmen

Once the ground around the pipes warms, it melts snow. And water will really draw heat away from the tube. High wood consumption usually indicates high heat loss in either of these two places.

Control-ability and buffer interface is another seperate issue, but not often a high wood consumption snafu.

hr

 

[Burn-1]

GW = Greenwood I'm assuming?