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Actuator Replacement

newinnj Member Posts: 37
I have existing Mr. Pex thermo actuators that are about 15 years old and are working fine. The six circuit manifold needs to be replaced. It was from a bankrupt company called radiant direct.com I am going with a six circuit stainless steel manifold from Watts. Watts wants their actuators on their manifold after a phone call I made to them. The installer prefers to go with new ones and get Watts. What is everyone's opinion on it. I am thinking the existing actuators are generic and could go on the new one. The question is how long do actuators last and what is the opinion on paired manifold to acutators that the manufactuers are selling on that idea. Thanks for any assistance.


    HVACNUT Member Posts: 5,870
    New manifold with new actuators. Save the old ones for spares if they do in fact work with the new manifold.
  • Dave H_2
    Dave H_2 Member Posts: 556
    Actuators and manifolds are typically not interchangeable, especially when we get into older systems. The travel (throw) of the valve in the manifold can be different an the way an actuator mounts on the manifold can be different.
    The actuator head may be interchangeable, but the collar that was used is designed for that manifold.
    As @HVACNUT said, use new actuators and if interchangeable, keep the old heads as backup.

    Dave H.
    Dave H
  • hot_rod
    hot_rod Member Posts: 22,334
    There are a handful of actuator manufacturers that private label their products to many radiant brands.

    You may find a replacement possible if you could determine the original manufacturers

    If you go with all new you’ll find most all new actuators are low current draw, 250 Ma. So you will save some electricial consumption also with an upgrade.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • newinnj
    newinnj Member Posts: 37
    No emergency here just a general question. I know everyone is really busy with the heating season starting. I would like to thanks everyone's advice on this so far. The new manifold and actuators have been installed. Now something for the first time for this system is happening. It is working as designed. When one zone is calling for heat the other zones tubes don;t heat up like it used to. Now for my general knowledge I would like to know the issue that was happening before. The old actuators when called for heat will take some time and then open up. Then the pumps will start up and the boiler will fire up. I am thinking there was full flow with them open. Was the issue with the actuator on return side and or the flow meters on the supply side manifolds? The symptom was regardless which zone called for heat all the zones will get heat. This is even with the acutuators for those zones not opening. Does that mean that something was stuck open and the actuators were just doing signalling between thermostat and boiler and not really controlling any flow? The flowmeters were so old that one could barely read them and they looked like there was always full flow. A second question for the current setup is that I can control the new flowmeters. Is that should be only used for specific circuit work or purging? At this time none of the flowmeters are showing greater than a 1 gpm and does that mean the adjusting spindle where the actuators are is what needs to be adjusted? Thanks for any insights.