Building my own OWB couple of questions

[6gears]

I have been looking around the net for a couple of months and started building my own wood boiler. I have got most of the bases covered about size, water capacity, etc. I have some questions about the plumbing side of the whole system. I have 6 loops installed in my workshop which is 32x48. I bought the manifolds with the small pex valves pre-installed from Menards. I have an ITT bell and gossett circ pump for the system. I hope to run my boiler at 160 to 180 degrees. I understand that I should only put 100 degree water into my slab. How should I plumb my pump and mixing valve into my open (non-pressure) system? Can I pull water through the mixing valve? This would be the easiest way for me to put the pump on the boiler and push water through the whole floor system. The pump would only see the 100 degree water. I have looked everywhere for a simple plumbing diagram to no avail.. Any suggestions would be appreciated. Thanks, Brian

 

[bassman]

I am in the middle of the same thing.
injector pump with many other parts .
I will post later

shayne

 

[Al Smith]

I can't tell you what temp,but a little story.My good buddy,now in the promised land heated an addition to the office of his trucking company,about 24 by 36 using a large residential water heater and a recirc pump.

Would you believe all he used was soft poly well pipe and never had one bit of problem.Once the slab is up to temp it isn't hard to maintain.Lots of help on the web,"google"

Oh,a tad off the subject but interesting.Old Darrel also built the first fully operational aticulated tractor that worked properly in the US of A.John Deere was so impressed they checked it out before building their own.Anybody that thinks farmers are dumb haven't met them all .

 

[Husky137]

For efficiencies sake I would use some sort of heat exchanger. Use the 180 degree water to heat other water so that the two systems are exclusive of each other. It would be very inefficient to heat the circulating boiler water to 180 and then temper it down to 100 and then return 90 water to the boiler to be heated back up to 180.

 

[ericjeeper]

Tempering valves are available

You won't have any problems in using a tempering valve, just recirculate some of the return from the slab water into the mix.

 

[alan mesmer]

I designed and built my own OWB 3 years ago. I decided on a forced air combustion system to minimize the chance that it wouldn't burn properly and I have not had a problem. I obtained all necessary parts from Grainger including the aquastat, blower, and pumps. Pex tubing and fittings were obtained from farmtek. I bought the 1/4" steel from a local burner and welded it myself. The unit has a 40" long x 36" dia. burning chamber with a 28" door. I can burn most logs that I am able to lift and can burn just about any kind of wood including green without too many issues. I am sure that my unit is not the most efficient but I still get a 12 hour burn and keep the water at 175 deg and the best part of it is I have about $2500 in the whole thing. I have a heat exchanger on my forced air system and have heat to spare. I am soon going to build my shop and will be putting pex in the floor for sure!

As others have suggested, as long as you have a mixing valve you will be fine. If this makes any sense; I am told you are basically diluting the water that goes into the floor with water that already has gone to the floor via. a circulating pump, mixing valve, an aquastat, and/or thermostatically controlled 3 way valve. Try the central boiler website for a example diagram.

Give me a yell and I will be happy to share all learned information.

Alan