radiant floor heat won’t shut off

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    • #276074
      Brent Rains

      I have a radiant floor installed in my bathroom attached to a boiler with three other baseboard zones. The radiant zone has it’s own circulator, flow check and mixing valve but no zone valve. It was working fine until I recently purged the system. Now whenever any of the three other zones goes on, I get hot water circulating into the radiant zone, even though the circulator is not kicked on. In fact the thermostat on the radiant is set to off. I checked and the water is flowing in the correct direction through the circulator so this alleviates a flow check problem. Pressure in the system appears right although it may be lower then previous setting. Any thoughts?

    • #293373
      Harold Kestenholz
      Participant

      If the flow check is working and the system is piped corectly, water from the other zones can not pass thorugh the radiant section as the flow checks all oppose each other.

      If you insist that water is flowing in the correct direction through the radiant circulator with the radiant circulator off, then the system is piped incorrectly.

    • #293374
      gkravatz
      Participant

      and handles the 3 baseboard zones. When this is non it does flow past the “T” connected to the radiant zone. There is no “supply side” flow check preventing water from flowing into the radiant zone and circulator when the main circulator on the boiler is on. Is this what is missing? There is a reverse flow preventer on the outbound side of the radiant circulator. There are no other flow checks on the system but each baseboard zone has a zone valve.

    • #293375
      Harold Kestenholz
      Participant

      Either the reverse preventer (flow control) is working so it stops reverse flow or it is not working. some water may flow into the radiant tubing because water flows past it making some mix flow there, but it should not go through and into the other loop enough to heat it if the radiant circulator flow control is working.

    • #293376
      gkravatz
      Participant

      Could the radiant circulator be broken? Will the circulator allow water to flow through it in the forward/upward direction when it is off? It is a Taco 7000.

    • #293377
      Harold Kestenholz
      Participant

      Yes, a Taco 007 (as do most of the circulators)allow water to pass through; that is why multi-zone circulators EACH have a flow control valve to prevent backflow and gravity flow.

    • #293378
      gkravatz
      Participant

      Okay, I think I’m narrowing in. To me it sounds like the flow control valve on the system is not working properly. My local plumber though says he has not seen one of these fail in 20 year. I went and rapped on it the other day in case it was stuck, and now when the baseboard zones go on it seems like I hear three distinct thumps coming from the flow control. Is this the sound of it opening? Could it be possible that it is undersized and that the actually gravity flow is opening it?

      Like you said in your reply, it seems that I do not get total garvity flow through the radiant…only half the floor seems warm.

    • #293379
      Harold Kestenholz
      Participant

      It is poosible gravity flow keeps it open, but unlikely. It is more probable there is something lodged in the seat to leave it partially open, so when the other zones open, the added flow taps the check to make the noise.

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