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Wirsbo mechanial actuator adjustment

paako Member Posts: 2
If one turns the brass nut pushing the zone valve down. How many turns counter clockwise to set. Also i used silcone spray to free a stuck zone valve, which i understand are not avalible now. Also dont understand the two red wiring. I see all yellow are tied togeyher. What about then 2 red wires.


  • mattmia2
    mattmia2 Member Posts: 9,653
    2 wires are the motor that actuates the valve and the other 2 are an end switch that signals when the valve is open. I think there is a retrofit to replace these if necessary.
  • hot_rod
    hot_rod Member Posts: 22,144
    The brass nut is the attachment nut, Usually hand tighten it until it stops. If the nut is not all the way down the that port may not close off completely. Don't force it with a pliers :)

    With the actuator removed, that port is all the way open.

    So basically screwing down that actuator closed the port, power opens the port.

    Those are getting hard to come by. They were sold as Sparco, Honeywell Sparco, and Wirsbo. Maybe a few others. Used to be a bunch on e-bay, not much there anymore.

    Maybe Uponor has a thermal motor replacement?
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • Dave Carpentier
    Dave Carpentier Member Posts: 589
    edited May 2023
    I only have 2 motorized actuators left out of the 7 original, as Ive been replacing them with thermal actuators (slow...). Thats cool that you have 6 working.
    What I do is remove the MVA, set the valve (black part inside the manifold) so that it's flush with the top of the brass hole that it's in. Then attach the MVA and adjust so that the indicator is at the green dot when it's not powered up. If your valves are getting tired, maybe inset the valve down a little.

    The yellows are the motor drive circuits, if they get 24v the MVA activates.
    The reds are the end switches.
    On mine, the room thermostats connect to one leg of the yellows to act as a switch which activates the respective MVA. The other yellow wire completes the circuit back to the transformer.
    One leg of my reds connect to a relay which powers up a circulator pump (common one for all zones). The other red leg goes to the transformer to act like a switch for the relay.

    If you have all the yellows tied together, then all 6 zones open together. Functional, but an expensive way to do a common feed maybe ?
    30+ yrs in telecom outside plant.
    Currently in building maintenance.
    mattmia2Alan (California Radiant) Forbes
  • Alan (California Radiant) Forbes
    Replacement Uponor actuators are A3023522. You will also need an adapter for that manifold which is A3019900 available here.

    Make sure the pin valves on the manifold aren't stuck. They should move up and down. If they are stuck, replacement valves are no longer available. You have to replace the whole manifold.
    8.33 lbs./gal. x 60 min./hr. x 20°ΔT = 10,000 BTU's/hour

    Two btu per sq ft for degree difference for a slab