Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers WITH EPA-Certified Models => HeatMaster => Topic started by: schoppy on November 09, 2018, 09:46:12 PM
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Just wondering what you G200 owners/dealers are seeing for total GPM flow at your units when running 2 loops? Max vs. required vs. minimum flow for good operation?
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I think recommended flow is 16 gpm? I usually do a loop to the house 4-8 gpm. Then a recirc loop using 1" pex and an NRF-22 . Not sure on the flow but with that short loop I would think it's over 10 gpm.
Actually that's on GS models, G200 now has built in recirc pump that supplies all the flow it needs.
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On mine I have two Armstrong ECM pumps. The display on the one to the house shows about 6-7 GPM.
The other is the recirc loop connected with 1-1/2" pipe runs at 16 GPM.
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Yes, the factory recommends 16 gpm so I inquired further about less than the recommended total flow. I was told if you are using both sets of supplies/returns and getting proper temps from the supply that there shouldn't be a problem with lower than 16 gpm total flow. Last year I did not have to add any water during the heating season so I am definitely not boiling off the water.
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Has anyone taken temps of the flue gas exiting the stack while running full out? I wonder what if any affect reduced gpm flow would have on stack temps and if this would correlate to running efficiency?
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With less than ideal flow rates if might stratify a bit. It might start to supply cooler water temps even tho the control is reading 180 up at the top.
So if it's mixing ok I wouldn't worry. I've never heard one boil inside around the tubes so I'd imagine it would have to be pretty low flow to affect efficiency.
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Thanks E Yoder. I have done digital temp checks on the supply lines at the back of the boiler and where they enter each of my buildings to check on the temp loss of the lines. I found the temps at the back of the boiler were right at the temp on the units control and only had 1 to 2 degree drop in my lines. About 1 degree for the house (95 ft.) line and 1.5 degrees on my shed (150 plus ft.) which I thought was pretty good.
Does anyone have an idea what the exhaust flue gas temps usually run?
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stack temps on my G200 with over 20GPM flow (3 pumps hooked up), my flue gas temps averaged 350-475 on hot burn cycles with seasoned oak.
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Thanks d5knapp, I have never checked my stack temp but I think I will for the heck of it this winter. I have 3 speed pumps for my loops and I will check the temp on all 3 speeds to see if there is any difference.
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I'd like to see to the results, I've never checked my stack temps.