Welcome! Here are the website rules, as well as some tips for using this forum.
Need to contact us? Visit https://heatinghelp.com/contact-us/.
Click here to Find a Contractor in your area.

One zone will not circulate hot water heat

I have a 7 zone radiant system. One zone is not working. All other zones seem to work fine. 12-15 psi on the system. I have taken off the control valve motor and manually turned on the station that does not work. There is a high bleeder valve on the return side, which I have opened expecting water to come out after the air escapes. Water does not come out. I am suspecting I have air in the line on this one station. Any suggestions on what to try next?


  • psb75
    psb75 Member Posts: 563
    open the bleeder and purge the zone of air, until water comes out. You'll have to isolate that zone and "push" water through it. No flow indicates that it is "air bound." Of course this procedure is dependent upon how your plumbing has been put together with isolation valves and purge valves. If you are not able to push water through the zone, it may be blocked. But first, assume that it is "air bound."
  • Ironman
    Ironman Member Posts: 6,868
    Temporarily adjust the fill valve to 25 psi while you try to purge the air from that zone. Make sure all the other zones are valve shut so that the air doesn't go into them. Once you get a solid stream of water from the purge valve, lower the static fill pressure back down to 15 psi cold.
    Bob Boan
    You can choose to do what you want, but you cannot choose the consequences.
  • john walsh_2
    john walsh_2 Member Posts: 62
    edited January 2017
    When did the zone stop working? Was work done on the boiler or system?
  • bill18675
    bill18675 Member Posts: 4
    No work was done on the system, however I put a second gauge on the system and there is only 2 PSI instead of 15 like the other gauge says.
  • bill18675
    bill18675 Member Posts: 4
    Thanks for everyone's suggestions. I think I must have a bad regulator.
  • bill18675
    bill18675 Member Posts: 4
    Raised the PSI to 12 and was able to purge the system. For the other newbies out there. The lever on the regulator pushes a shaft down to bypass the regulator. I did not know that. Once I raised the water pressure the system started circulating and it was easy to purge the air. My only task is to replace the regulator on a warmer day.
    rick in Alaska
  • dieselb2005
    dieselb2005 Member Posts: 2
    I had something similar happen here in NJ. Basically ground level zone had no hot water circulating nor could i flush out the water from that zone. felt like something was stuck/clogged. the other 2 zones (2nd / 3rd floor were fine. after 6 hours of youtube videos etc, it occurred to me that maybe the zone had a frozen section and due to the weather dropping to 7 degrees overnight.

    Surely that was it. Waited until the weather went to over 40 and basically everything works fine now and flushes fine and heat is restored.

    lesson: since i have my boilers in the 1st floor next to the thermostat, this zone essentially never turns on overnight especially if you have it set to 65. the water heaters and boiler naturally keep the room above 65. so i will set it to 73 when the weather drops below freezing so the zone activates and doesn't freeze.

    hope this helps.