Outdoor Wood Furnace Info
Outdoor Furnaces - Manufacturers WITH EPA-Certified Models => Central Boiler => Topic started by: sabercat on December 19, 2016, 11:14:22 AM
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Recently I believe I had a air lock in my water system. Reason for this thinking was that my air/water exchanger was not all completly hot, when the fan would kick on, the only hot part of the exchanger was in the center (18x18) veins. So thats why I thought maybe airlocked. I first back flushed my system, but didnt really notice a difference. I had a brandnew B&G 22 pump, read that it had a little gpm then my 007, so replaced the 007, no differance. I thought well maybe the exchanger was plugged, so got a good deal on a new one, installed it this weekend, and I believe its alot better, but still the hot side in is very hot, and the exit side is almost as hot. Now the fan kicks on, and in a few minutes the exit side is very cool to the touch, center and enter side hot. You can hold you fingers on probably the top (return) 5 rows of tubes, actually cool to the touch.
When I intalled the exchanger, got all the air out etc. I think, could be wrong, even when the fan is pulling air thru the exchanger it should still be fairly warm to the touch, on the return top tubes.
So what are my options, bigger pump? Or maybe slow the return down somewhat, keep the hot water in the exchanger a few seconds longer.
My exchanger is mounted to the furnace, in and out lines come up thru the floor, goes thru the exchanger, then back down to the stove.
Stove is probably 130 feet from furnance, then it goes 50 feet to polebarn, which is just a loop for now. The entire loop (didnt relize it was this many Feet)from stove back to stove is roughly 388+ or - feet, that with the rising to the sidearm, furnace, and in the polebarn. Thanks for any help.
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Taco 007 or B&G NRF 22 are way too small.
You need at least a 0011, NRF36, pl36, Grundfos 26-99, or something else with at least 30' of head pressure.
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sounds like a lack of water getting to the exchanger. flow, air lock, pump size, head loss all could be a factor
What size pipe are you running from the stove to the exchange? Also - what is your elevation difference from A to B. As RSI said you may need a bigger pump, if your pipe can handle the volume.
also - did this ever work in the past? if so what changed? (ie, added a loop/zone, etc...)
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sounds like a lack of water getting to the exchanger. flow, air lock, pump size, head loss all could be a factor
What size pipe are you running from the stove to the exchange? Also - what is your elevation difference from A to B. As RSI said you may need a bigger pump, if your pipe can handle the volume.
also - did this ever work in the past? if so what changed? (ie, added a loop/zone, etc...)
1" pipe size
pretty flat from a-b
it use to work in the past, but I did have a different pump on, not sure what size, Ill look tomorrow. The pump went out this fall, replaced it with my back up a 007, then put the nrf 22 on a week or so ago. I did add a loop on 2 years ago, 70 feet or so with a 6' lift. I've use wood for 16 years, this has been the worst as far as heat coming out of the vents. I also have the thermostatic valve mounted in line for the central boiler warranty, in which I have been thinking seriously about removing. Its working better, since the latest pump change and I did order a bigger pump yesterday.
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Do you know if the thermostatic valve is working properly? There were a couple people here that had them fail this year.
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forgot to add, I have always burned a lot of wood, about 30 face cord a year, but sometimes would start in sept, and go till may. pretty well insulated home, 6" walls etc, 1528 sq feet. Heat domestic water also, sidearm
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Do you know if the thermostatic valve is working properly? There were a couple people here that had them fail this year.
not sure, but I do have hot water going thru it. I was never a big fan of it though.
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Check temp of the return from the house going into it compared to return to boiler coming out of it.
If the return from the house is fairly cold then it is probably not working right. Would be best to do while blower in house is running.
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Do you know if the thermostatic valve is working properly? There were a couple people here that had them fail this year.
What I was gonna ask as well, you’re symptoms sound very familiar.
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Check temp of the return from the house going into it compared to return to boiler coming out of it.
If the return from the house is fairly cold then it is probably not working right. Would be best to do while blower in house is running.
I'll check tonight
The old pump that was on for 15-16 years was a Grundfos 15-42F, not sure of the specs on it.
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http://www.pexuniverse.com/docs/pdf/gr-59896155.pdf (http://www.pexuniverse.com/docs/pdf/gr-59896155.pdf)
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I had a problem several years ago where I was having to throttle the water going through my heat exchanger to force more through my plate exchanger used for hot water I expected the plate exchanger to be fouled but found that my taco pump 007 had started going bad over a period of time. The impeller was found to be almost nonexistent. I replaced the taco pump with my spare pump and everything has been back to normal. :thumbup: