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

Zone valve / steam 1 pipe / thermostat

David11 Member Posts: 4
Hi everyone,

I am living in a building with a 1 pipe steam system. The boiler is in the basement and is the same for all the apartments of the building. My problem is that one of my room is often too hot and I am trying to find a solution (without manually turn on/off the valve).

I know about TRV but since my radiator is in an enclosed space it won't really work (and I don't want to put these TRV with wired thermostat).

I have a Nest thermostat controlling my AC system very close to this radiator and I was thinking to put a zone valve just before the radiator (and after the manual valve), and control this zone valve with my thermostat. I have few questions:

- I understand that zone valves are not really a good idea for one pipe steam heating system but I don't see where is the problem of putting a zone valve at the end of the line just before the radiator (it will basically work as a manual valve). Is it really a problem? Could I possibly do that?
- The boiler is independent and I do not want to control the boiler with my thermostat but only the valve before the radiator in my room. Can I control a zone valve with the Nest Thermostat without being connected to the boiler?

I understand that there is some limitations: If my thermostat call for heat and open the valve but the boiler is not on then the radiator won't work: it's not a real problem for my situation.

Is my idea doable?

Thanks a lot for your help!


    EBEBRATT-Ed Member Posts: 9,086
    edited April 27
    Zone valve won't work on 1 pipe steam. Water will trap in the radiator and cause hammering. A TRV mounts on the vent end of the radiator, that is the easiest way to go that will work. They make different thermostats for the TRVs some are remote mount so you may be able to find something that will work. Look at Supply

    Other things to try are putting a standard adjustable vent on the radiator and blocking the air in and out of the radiator
  • David11
    David11 Member Posts: 4
    Thanks for your reply!
    What is the difference between a manual and a zone valve in term of hammering? I am not sure I understand what is the physical different between a zone valve and a manual valve that you manually close/open.

    I would prefer to avoid the TRV solution because I would prefer to be able to manage the temperature via my thermostat and I did not see any TRV capable of doing that. Did I miss one?

    I will investigate the adjustable vent but seems to be a too dangerous solution. I am scared that the inside box with the radiator will be crazy hot!

  • ethicalpaul
    ethicalpaul Member Posts: 3,014
    Before you get too high tech, I strongly suggest just putting a blanket over part or all of the radiator. It is by far the easiest and easy-to-adjust way to effectively make a radiator smaller
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • David11
    David11 Member Posts: 4
    Thanks ethicalpaul. Sometime is too hot, sometimes not. My goal is to not have to manually turn on/off the valve or put/remove a blanket (especially because the radiator is within an enclosure).

    It's why I am trying to see if a zone valve, connected to my thermostat could work. I understand that it could potentially creates some hammering noise, but does not really see why it would create more hammering noise than turning a manual valve on/off.
  • ethicalpaul
    ethicalpaul Member Posts: 3,014
    Turning the manual valve on/off will often result in condensate build up and/or water hammer or gurgling, all kinds of issues. The valves often don't seal completely especially when old.

    It's already in an enclosure and still overheating the room? I missed that. Is that the "enclosed space" you referred to in the original post?
    1 pipe Peerless 63-03L in Cedar Grove, NJ, coal > oil > NG
  • David11
    David11 Member Posts: 4
    Yes sorry for my English! :)

    Yes that still overheat the room.
  • dopey27177
    dopey27177 Member Posts: 534
    You can extend a piece of pipe from the vent fitting to outside the enclosure and put the TRV out sud the box.

    The TRV only operates the vent valve and will not cause banging, no need for a TRV.

    When you close a radiator valve on one pipe steam often some steam will pass the seal of the valve and collect in the radiator. The problem is often the water will not drain out of the radiator and when steam will work its way into the radiator (to coin one of Dan's terms) you will hear the hammers of hell.

Sign In or Register to comment.


It looks like you're new here. If you want to get involved, click one of these buttons!