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Z-Wave Thermostat-Valves + Steam

Hi. I see things like these radiator valves with built-in thermostats and wonder if I can use them to better balance my system, and save money through more precise and tailored steam delivery. I have a four-story house with a one-pipe steam system and around 16 radiators. If i used this type of TRV on all rads, and was able to say manually cycle the boiler 1-2 times per hour until all rads were brought to their respective temps, I'm thinking that might be interesting system? Any thoughts on that approach? Not sure what device I would use to fire the boiler, and keep it running until all rads were satisfied. Probably a master thermostat, that could do room averaging with multiple sensors? Hmmm.


  • Jamie Hall
    Jamie Hall Member Posts: 23,653
    Keep in mind a few basic points here. First, you need to have your entire system in balance to begin with. The main venting has to be more than adequate, and the radiator vents have to be chosen or adjusted so that without any intervention the building heats reasonably evenly. Unless that is true, you're applying a band-aid, not a solution.

    Second, one pipe steam has to be controlled by the vents. It is not entirely clear from the manufacturer's literature whether this device is intended to control the vents, or the radiator inlet valves. however, the literature does state that the thread is M30 x 1.5, which is a not uncommon thread for metric plumbing, and is more ore less the same size (though not thread pitch) as a 1 1/4 inch US or BSF thread, but with no taper. This is not a suitable thread size for a vent, which leads me to believe that this device is not suitable for controlling a one pipe steam radiator.
    Br. Jamie, osb
    Building superintendent/caretaker, 7200 sq. ft. historic house museum with dependencies in New England
  • EdTheHeaterMan
    EdTheHeaterMan Member Posts: 8,167
    edited October 2020
    I would contact the thermostat manufacturer to see if they recommend a valve for steam vent operation.

    One of my "Go-To" sources for Hydronics has a small blurb on the subject http://media.blueridgecompany.com/documents/ZoningMadeEasy.pdf
    The discussion about these valves starts on page 20 however you are more interested in the info that starts at the bottom of page 23 "ZONING ONE PIPE STEAM SYSTEMS"

    Of course, what @Jamie Hall says, it is more important to have a properly operating system first. These are for minor adjustments in room temperature for individual occupants' needs.

    Edward Young Retired

    After you make that expensive repair and you still have the same problem, What will you check next?