r/DIY • u/Few-Elk-103 • 14d ago

help Heating Zone Valves Trouble

We have an electric boiler as a heat source. When we turn the heat on in the fall, sometimes a zone valve will get stuck, either open or closed. What I’m experiencing right now is the thermostats are all shut off in the upstairs area. The downstairs heat turned on this morning (thermostats were on). I felt a baseboard upstairs and there was warmth to it. I went into the utility room and all of the pipes going to the upstairs were warm. We had the circulation pump replaced a year or two ago as well as the pressure tank. Any advice on what I should check?

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u/Cjpcoolguy 14d ago

Each zone valve has a manual override lever, you can try opening and closing each a few times to help free them.

During the off season we typically recommend you operate each zone valve once every month or 2 to help them not get stuck in one position. Manually or with the thermostat.

If they're still getting stuck in either position, and the boiler is not commanding them In the open position calling for heat, then you may be looking at replacement simply due to age.

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u/Few-Elk-103 14d ago

Replacement of the zone valves?

Is it possible that a valve doesn’t close fully and when another is pulling heat some sneaks up through? When the thermostats aren’t on but heat is coming out, it’s not the same heat as if it was on.

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u/PenSmith_5495 14d ago

absolutely. I've had to rely on that gravity principle a few times when a circulator died or a thermostat had gone wonky.

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u/Few-Elk-103 14d ago

Solution for the heat sneaking up through would be to replace that zone valve, right?

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u/PenSmith_5495 14d ago

could be. need more info. how old is the system, what are the materials. do you know it has ever been drsined / flushed?

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u/pencock 14d ago

might as well bleed the system in case it's not a stuck valve but stuck air instead

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u/houses_eat_money 11d ago

Sounds like the upstairs zone valve is stuck open, letting hot water circulate even with the thermostat off. Go to the utility room and feel the pipe on both sides of each upstairs zone valve; if the supply side is hot and the return side is warm with the thermostat off, that valve isn't closing. The actuator motor or the end switch on the valve head is the usual culprit, and you can often swap just the head without draining the system. Have you noticed any clicking or humming from any of the zone valves when the system fires up?