Had boiler installed, doesn't work correctly! Please Help

[IACG]

Do you have an estimate of how much energy you want/need to dump into the house? If so I can plug that into a spreadsheet to compute gpm, velocity, and head based on your 1" pex which will tell you if the pump's adequate. Unless you have a very efficient home that's not too large, 1" is pretty small for those distances. Which means to move more btus/hr you must increase velocity, which increases head, which increases pump horsepower.

Somehow get the temp of the water entering your underground and the temp where it exits to get the temperature loss in underground. I lose about 1* or less in about the same distance (2*F round trip including thru the HX when fan's off). The source of our boiler said 1" would be adequate, but I did the math and installed 1 1/4"... for our boiler which is roughly in your class, our install would be more efficient with 1 1/2". I was in similar circumstances 6 years ago and the guys here helped me sort it out. In my case years ago it was multiple problems I needed to address. But checking pump size is a start. The diagnosis process often involves going down the list identifying what it's not.

BTW.... Did you read the underground sticky? The pipe drain I used for my first underground was not perforated, but when I sprayed foam inside I was shocked to see all the tiny pin holes. When I dug up my first underground install it was all filled with water and mud. I was losing a huge amount of energy to the dirt. Yes... too bad you discovered this site after the fact, but you'll get lots of great help here.

I don't have a number for the estimated heat I need in the house. Here is what I have in the house currently: The furnace has 18 kilowatts of elements. The house by the way is just under 2000 square feet. It is a one and three quarter story and it extends over the garage. The living room has a vaulted ceiling open to a loft. I would have to do some figuring as far as volume is concerned. I also have a wood stove in the living room which we try to keep going most of the time. I want to use it less once I burn wood in the boiler though I don't plan to stop burning in the house. The attached garage is approximately 675 square feet.

 

[maple1]

I asked him about the thermal shock having such a large Delta T. He says that it is not a problem. He contacted the manufacturer and they too say it is not a problem to send back really cold water. The told him, "The only way that it could potentially become an issue is if you had very cold water ( close to freezing continuously running back to it.) With the way its set up the water that runs back to the boiler instantly mixes with the other 150 gallons that are already in there, so it is highly unlikely that it would ever become and issue."

This does not solve the large Deta T issue, but the dealer assures me that I would be wasting my money buying a mixing valve and such to warm the return line from the house. In fact, he figures the added resistance would cause even more of an issue.

Still leery about this stuff. It's not so much 'thermal shock', but rather extended periods of sub-140 water returning & causing increased creosote condensation inside the boiler. This would be the case with every other wood burning boiler I have heard of - but this does seem like a different beast, so not sure what to say.

 

[Karl_northwind]

I would pipe it up primary secondary. something like 1.25" pipe from top port to bottom port, with a 15-58 (or grundfos alpha) pumping from bottom to top.
have a series of tees in that pipe, that allow hot (bottom) to be pulled off (via the 2699 to the house, and the other circ to the shop) and the cold return back in to the top of the boiler. a standard primary secondary setup, which will keep the return temps up, the proper flow rates for the boiler, and all will be happy.
the distribution flow rate to the house is a separate issue.

the 2699 ought to push about 5-6 gallons per minute thru all that PEX. that's going to return a really high delta T if it does the load at all.

separate the boiler operation criteria from the heat distribution issues.

karl

 

[slowzuki]

Gasifiers aren't as critically sensitive to return temps for burning but it can cause condensation inside the heat exchanger that will shorten the life. There is still the problem of load management if you don't have return protection. Too much load will drag the boiler temp down and prevent you from having high temp water for your high temp loads.

Stirring the boiler isn't going to fix that, the heat absorbed in the primary chamber should be well under 1/2 of the boiler output, somewhere around 1/4. Capture of that with stirring isn't going to solve your whole boiler being dragged down when your slab loads are both calling.

I asked him about the thermal shock having such a large Delta T. He says that it is not a problem. He contacted the manufacturer and they too say it is not a problem to send back really cold water. The told him, "The only way that it could potentially become an issue is if you had very cold water ( close to freezing continuously running back to it.) With the way its set up the water that runs back to the boiler instantly mixes with the other 150 gallons that are already in there, so it is highly unlikely that it would ever become and issue."

This does not solve the large Deta T issue, but the dealer assures me that I would be wasting my money buying a mixing valve and such to warm the return line from the house. In fact, he figures the added resistance would cause even more of an issue.

Still leery about this stuff. It's not so much 'thermal shock', but rather extended periods of sub-140 water returning & causing increased creosote condensation inside the boiler. This would be the case with every other wood burning boiler I have heard of - but this does seem like a different beast, so not sure what to say.