2 way valve not operating; replace all or just actuator motor.

Discussion in 'Plumbers' Talk' started by SteveMJ, Nov 23, 2021.

  1. SteveMJ

    SteveMJ Active Member

    Hello Folks,

    I'm seeking your opinions.

    I have a Honeywell 2-way valve that is not closing on command. I have removed the motor and can open/close the valve manually with pliers. I've left it closed for the moment as all the heating water was going through the HW cyl and not the house = very hot water from taps etc, not very hot rooms in my home.

    I am wondering if I should replace the whole valve or just the actuator? I might even see an obvious fixable fault with the actuator motor later when I get it out of the loft.

    The valve has been there 20+ years, is the valve body itself likely to need replacing? My aversion is that the actuator replacement is easy, whereas the valve body requires part draining the system. Oh and its winter so there is bound to be some c*ck up in draining and refilling, ha ha.

    (I have another question about actuator valve's microswitch that I will ask as a seperate item)

    Thanks for your advice.

    Much appreciated as always :)

    Last edited: Nov 23, 2021
  2. Teki

    Teki Screwfix Select

    Can you operate the valve stem with your fingers? It could be an ageing valve/actuator or sludge in the system.

    It would be best to replace the entire valve and actuator but if you haven't done it before, probably not a DIY task especially in winter!
  3. SteveMJ

    SteveMJ Active Member

    Thanks Teki,

    Fingers weren't quite up to it, but easy with some long nosed pliers that I had to hand.

    If I drain system, I'd add a Maganclean filter that I bought a while back, but have procrastinated about fitting. I was intending to fit in warmer weather when if a problem arose the temprary loss of heating isn't a big problem.

    Hmm , I could buy a complete valve and just fit the actuator for now and fit the valve body when warmer - that may be a workaround with less risk. I presume that all 28mm 2-way Honeywell valves have the same actuator interfaces?

    Thansk again, Steve
  4. Teki

    Teki Screwfix Select

    That sounds like a plan. You may as well drain the system once to fit the new valve and Magnaclean. When you fit the new actuator, remove and replace one wire at a time to avoid mixing them up!

    Can you post a photo of the valve area and also where you propose to fit the Magnaclean?

    Have you done any plumbing work before..
  5. SteveMJ

    SteveMJ Active Member

    Hi Teki,

    You may as well drain the system once to fit the new valve and Magnaclean. That occurred to me as I was typing my earlier reply. I woul dleave the valves intheir current location - been OK for 20+ years now.

    The two boilers and HWC etc are all in our loft, boilers one end and HWC etc at the other, above the kitchen where the original 1970s boiler was fitted. Before my time of ownership though. This leaves a long straight 7m+ run where I am going to fit the Magnaclean - on the inlet to the boilers.

    No photos tonight though ;-)

    Cheers, Steve
    Last edited: Nov 23, 2021
  6. SteveMJ

    SteveMJ Active Member

    I went up to check size and look for a model number to enable buying a replacement. Pipe size is 22mm.

    Yes, I have plumbed before (I did my son's whole house) and not really plumbing; I designed some of the thermal control for https://en.wikipedia.org/wiki/European_Retrievable_Carrier. The prototypes for electrical heaters.
  7. Teki

    Teki Screwfix Select

    There are signs of water leaking around the valve previously. May be worth lifting the insulation off and tracing where it may have come from.

    What is the part number on the actuator?
  8. SteveMJ

    SteveMJ Active Member

    Hello Teki,

    I look at the leak when I replace the valve next spring. I am now waiting for my local Screwfix to notify me of click and collect for a whole valve.

    The old part that I have removed in marked "Honeywell F2 9751".

    I have removed the old valve acuator head and identified that the problem is worn gears - they are slipping. A search indicates that repalcement gears are NOT available.

    Thanks for you ongoing support :)
  9. Teki

    Teki Screwfix Select

    Yes, motors and microswitches are available but I haven't come across gears.

    Replacing the actuator may solve your immediate problem. You can replace the valve and address the leak issue when the weather is warmer!

    Just remember to replace each actuator wire one-by-one to avoid confusion or take a photo of the wiring centre before replacing it.
  10. heatyman

    heatyman Well-Known Member

    When the actuator is removed, the gears always slip on Honeywell valves. If you buy a new one, that will slip until it is on the valve body. If jammed open, it will be the synchron motor. If you replace that, make sure you use a real synchron, made in the USA. Available from our hosts as a Drayton spare.

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