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Author Topic: 2 circulator pumps but only 1 zone... why?  (Read 1845 times)

BNice89

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2 circulator pumps but only 1 zone... why?
« on: April 05, 2018, 05:49:27 PM »

Hey guys,

Another newbie question. I have 2 circulator pumps on the back of my OWB but only one zone in the house. Can anyone explain to me why this might be? It looks like the piping for the one circulator comes out of the furnace through the circulator pump and right back into the furnace. Am I wrong to think that this is just circulating water through the water jacket?

Thanks,
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E Yoder

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Re: 2 circulator pumps but only 1 zone... why?
« Reply #1 on: April 05, 2018, 06:34:32 PM »

Does the house pump start and stop with the thermostat? Likely the other pump is there to stir the tank to prevent layering and boiling on warm days.
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wreckit87

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Re: 2 circulator pumps but only 1 zone... why?
« Reply #2 on: April 06, 2018, 02:47:45 PM »

Not familiar with Mahoning, but a few times I've had to add a mixing or "shunt" pump just between the ports like that to keep the stove temp more even inside with perhaps a low draw from the house loop. Had an old Woodmaster last fall showing something like 180 on the aquastat, only sending ~165 to the house, and audibly boiling up above the loading door (these are approximate numbers, don't remember exactly). Added a small shunt pump on the second set of ports and it stopped boiling as well as raised the supply temp ~10 degrees due to the more thorough mixing. Had a couple Portage and Main units with similar issues that were fixed the same way. Heatmaster puts these pumps on from the factory on their G series I believe
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MattyNH

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Re: 2 circulator pumps but only 1 zone... why?
« Reply #3 on: April 06, 2018, 08:49:49 PM »

So I'm assuming you have your boiler fired up?. If so are both the pump running?
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shepherd boy

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Re: 2 circulator pumps but only 1 zone... why?
« Reply #4 on: April 07, 2018, 04:20:51 AM »

  Mahoning does run a shunt pump which should run any time the furnace is used. The zone to the house may come on and off to heat demand or can be constant run depending on the setup.
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