What do you fix when the Circulation Pumps won't stop running?

Old 01-05-11, 07:12 PM
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What do you fix when the Circulation Pumps won't stop running?

What makes the Circulation Pump STOP running?

I recently had an electrician do an overhaul of our circa 1970 hydronic heating system. He told me that two of the four end switches weren't working and they would cause my circulation pump to continue to run against the zones' CLOSED valves (which isn't good)

Indeed, you can hear the constant hum of the circulation pump (even after all the zones have reached temperature) and we have to switch the boiler on and off as the temp in the house requires (there's a light switch over the boiler to control power to the whole thing). Everything starts well and there is heat to all four zones; you just can't get the boiler to STOP pumping that water against the closed valves.

I have the Honeywell V8043G1018 valve on each of the four zones. I just took the valve head off to look at it. The yellow (and an orange?) go into the motor head and two red wires loop around under to what I assume is the end switch. It looks like I will have to unscrew the motor to get at the end switch and an added frustration is the screwhead design is unfamiliar (looks like a star - definitely not a philips)

First question is: Do you think it's the endswitch that tells the boiler's aquastat to shut down the circulation pump?

Second question: Is it easy to diagnose which two of the four valves has a faulty endswitch?

Third question: Is it easy to replace the endswitch?

Any help would be greatly appreciated!

--- as requested, I put this question into its own thread, but asking one question at a time? I think these three questions are fair to ask in one post, as one follows the other. Please let me know if I'm being unreasonable.

Old 01-05-11, 07:25 PM
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Kyle... you already asked the same questions... please don't start a new thread every half hour!

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