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Boiler hot, 2 zones, both thermostats turned "Off"

RadNewbie Member Posts: 4
We're hearing a whine lately from the 3-year old boiler. This is in a relatively small house with 2 heat zones, that use White-Rodgers zone valves. With both thermostats shut "Off", the top of the boiler is hot.

So to me it looks like the zone valve is stuck and emits a sound.

When I first had the zone valves installed (about 8-9 years ago), I did hear that these things break down fairly often and that I should have gone with circulating pumps.

My questions are: Is the heat zone valve the likely culprit? Do you think if I tapped it with a hammer, that would "unstuck" it for a while longer? Or is this a relatively expensive fix?

Thanks for any assistance. I'm in Chicago area.

(And when I was first renovating the basement, I remember this forum was awesome for getting great advice -- HVAC is kind of the weak link in my reno expertise.)


  • Tom_133
    Tom_133 Member Posts: 821

    If you post some pictures of your boiler and the piping we can probably narrow down the problem pretty quickly.

    Are you also making domestic hot water with your boiler?
    Montpelier Vt
  • RadNewbie
    RadNewbie Member Posts: 4
    Boiler hot, 2 zones, both thermostats turned "Off"

    I've attached a couple of images but don't know if they show enuf detail. Pretty tight quarters for the camera.

    The primary suspect is the main house zone valve because pipe is hot to that point, and so is the boiler housing.

    The basement zone is a monoflow system that shares a common return with the main house zone. The basement zone valve is in the upper end of the image.

    The boiler is not being used to make domestic hot water.
  • Zman
    Zman Member Posts: 7,330

    This sounds like a controls problem. When the zones are off, the boiler should not be firing and the primary circ should not be spinning. How long is it staying hot? Does the boiler call for heat?  I guess I don't understand exactlywhat is going on.

    "If you can't explain it simply, you don't understand it well enough"
    Albert Einstein
  • unclejohn
    unclejohn Member Posts: 1,757
    Are any rooms

    In the house getting hot? The way things should happen is Tstat calls and zone vavle opens. Zone valve end switch closes and send signal to boiler, boiler tells vent damper to open once damper fully open spark ign starts and boiler fires or if standing pilot gas valve opens when damper fully opens. If you have a standing pilot it may be that its generating enough heat with the damper closed to warm the top of the boiler and pipes.
  • RadNewbie
    RadNewbie Member Posts: 4
    Are Any Rooms

    No heat appears to be getting to radiators. I've got the boiler shut off at the breaker box, because as soon as I flip the breaker, the boiler fires up.

    Can the zone valve be manually shut off? There is a dial there, not sure which way to turn it on or off. I suppose I should just trial and error that -- on a cooler day.

    But still puzzled about the high pitched whine we could hear which is what initially made me check into what was going on -- it wasn't the heat in the radiators.
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