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mel rowe
mel rowe Member Posts: 324
Brad, I happened to notice this thread on TRV's ,so I wanted to throw this in. With all the condensate related problems I've had on one leg of my system, someone suggested that switching from the Honeywell TRV to one with a built-in vacuum breaker would fix the problem. So at the end of last year I bought a Macon TRV. It did me no good at all, because apparently the vacuum breaker valve will not operate. I talked to someone at the company and have played around with it a lot, but with no luck. Just recently I decided to try a Danfoss TRV. It has worked great. Since I insstalled it, I have had no more gurgling in the radiator, and I haven't had to remove and dump water out like before. I know the vacuum breaker is working on this one because I can hear it pulling in air after it cools down. FWIW



  • Tim_41
    Tim_41 Member Posts: 153

    Iam gearing up to install 4 CI rads in my house. Will be using home run system to a manifold with TRV's on each rad. My question is the best TRV location. I have used them on panel rads before where they were located at the top. Would the TRV be located at the top of a CI rad also??
  • Norm Harvey
    Norm Harvey Member Posts: 684

    TRV's need to stop flow to the radiator, so they need to be installed on the supply or return piping to each radiator.

    Pabek radiators have some internal piping that accomodates the location.
    "We see the world as WE are, not as IT is, because it is the "I" behind the EYE that does the seeing"
  • Brad White_184
    Brad White_184 Member Posts: 135
    Some other thoughts

    As Norm said, it does not matter which side they are to be installed so long as they stop the flow when necessary.

    That said, make sure that the flow direction and head direction are correct. If installed backwards (flow toward the top of the seat versus up through the seat) they will chatter.

    Also, if the thermostatic head is vertical above the valve, at least on some models, the convection from the piping will give a false reading and shut down the valve while the room is still cold.

    Now, you are using a homerun system which is great. You can also get thermostatic heads for the manifold but this of course will require some wiring and space thermostats.

    Personally, I would stick with TRV's at the radiators for simplicities sake, but you do have an option if you really like wall-mounted devices or want the familiarity of a wall thermostat.
  • TRV Source

    My local supplier has been trying to get me one without any luck. Can anyone give me the name of a good manufacturer? Thanks, Bob Gagnon

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  • Brad White_184
    Brad White_184 Member Posts: 135
    Macon Controls

    Represented by Tunstall Associates. I like the compact valve bodies and heads.

    I have a mixed bag in my own house and like the Macon valves the best. They use a 12 or 13 MM Allen wrench instead of a spud wrench so the installation is positive and easy in tight confines too.
  • Thanks Brad, that was fast

    Your the best. I have been waiting for my supplier for a few weeks now and it took you only a few minutes.
    Thanks, Bob Gagnon

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  • Brad White_184
    Brad White_184 Member Posts: 135

    Hi Mel-

    I would not take a malfunctioning vacuum breaker as anything but what it is. They can be replaced and can malfunction as with any part. Glad you found what worked for you but sorry you felt you had to replace the valve entirely. Sort of like throwing the baby out with the bathwater.

    Danfoss and Amaark (sp?) also make TRV's with integral vacuum breakers. All are good; any can fail.
  • mel rowe
    mel rowe Member Posts: 324

    Thanks Brad. I didn't really throw away the Macon valve. I was just very desperate to find out if lack of a vacuum breaker was causing the condensate to be retained in the TRV and causing the noise and lack of heat. Apparently that was the case. I did remove the vacuum breaker valve from the Macon TRV and try to find out why it was not functioning right. It is a very simple design-- a valve body and cap, with a lightweight spring and a wafer with a rubber o-ring that seals under pressure against the cap. With no pressure on the system I cannot see any possible reason for the valve not to function. When I talked to someone about the problem, they were unable also to explain why it doesn't work. I hadn't thought about replacing just the vacuum breaker valve itself, because I couldn't find any reason why it didn't work. However, this sounds like an idea I should try. Thanks again.
  • Tim_41
    Tim_41 Member Posts: 153

    Thanks for all of the replies. Do the TRV's mount on the top of the CI radiator like a panel rad? Or the bottem as if you were piping without the TRV. I will be using the ovontrop valves and head.
  • Brad White_184
    Brad White_184 Member Posts: 135
    Either way

    For CI radiators I have piped them in as "bottom inlet/top outlet", "bottom inlet/bottom outlet", "top inlet/bottom outlet" on opposite sides of course, without perceived unevenness.

    In my Susan's house (1922 converted gravity system with Arco large tube radiators now served by a Vitodens), all are bottom inlet and outlet yet heat up quite evenly. Contrary to what you may think, the water does not just "scoot" along the bottom of the radiator but rises into the tubes. On a cold start-up, the outlet stays cool pretty much until the radiator is warmed up.

    There may be a preferable way to pipe them but I have not seen a difference myself.

    For panel radiators, I would follow the manufacturer's recommendations. Some such as Runtal may have specific internal baffling.
  • Mike T., Swampeast MO
    Mike T., Swampeast MO Member Posts: 6,928

    As Brad says, connection locations on a cast iron rad are essentially immaterial as long as they're not on the same side of the rad. (Yes, I know there are special valves--even TRVs--designed for such.)

    Frankly, I'd use whatever connection method is already provided by the rad. Removing the old plugs from iron rads can be extremely time consuming and probably nobodys' idea of an enjoyable job.
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