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Weil McLain HE II calling for heat

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LRS1120
LRS1120 Member Posts: 2
edited February 2022 in Gas Heating
Hi all, I have a Weil McLain HE II-3 gas boiler sweating me out of my house - older unit, had control board replaced a few years ago, and both zone valves replaced about 13 months ago. A few days ago, my house was a sauna, inside temp about 15 degrees higher then set amount. I turned both thermostats off, and heat was still pumping out of the baseboards in zone 1 (first floor). Zone 2 (second floor) appears to be listening, just warming up from the rising heat in zone 1.

I turned the boiler itself off, and things took a few hours to cool down, but got back to normal temp. When I turn the unit back on, zone 1 is still throwing out heat.

Would I really need a new zone valve after a year? Is there something else that could trick the boiler into the call for heat in zone 1? Not super experienced with boilers, but want to give it a shot and thought I could try to save myself a contractor call .

Thanks in advance for thoughts and ideas!

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  • ScottSecor
    ScottSecor Member Posts: 856
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    Sounds like the zone valve is the culprit, assuming nothing has changed. Was the entire zone valve replaced or just the head/operator/motor. In some cases the body can actually pass water even with a brand new head.

    Once in a while we get a call with the same symptoms you describe, only to learn that someone just installed a new thermostat and wired it incorrectly. Not realizing that they are controlling two zones with one thermostat. Once in a blue moon, we find that someone accidentally put a nail or screw right into the stat wire and the heat runs non-stop, this call comes in about once every four or five years.

    What brand are your zone valves?
  • LRS1120
    LRS1120 Member Posts: 2
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    Thank you!  I installed new thermostats in each zone about 3 years ago, so they have been functioning as intended, but I did start there and make sure all wires were secure and in proper places. 

    The valves are Taco brand,  I believe just the head was replaced last year.  Didn't realize the base could be a separate issue.  I did disconnect the wiring for zone 1 and turned the boiler back on and that still resulted in heat pumping from the baseboards.  I'm guessing this could be the water passing through the body of the valve you referenced?

    Appreciate the help and suggestions!

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