3 port valve failure again.

Discussion in 'Plumbers' Talk' started by Deme23, Mar 8, 2021.

  1. Deme23

    Deme23 New Member

    Hi all, when i moved to my house approx 5 years ago we replaced the 3 port valve shortly after. I purchased a Honeywell copy and that didnt last long approx 1.5 years. Following that i decided to pay more for the honeywell but that didnt last long either (just shy of 3 years).

    The first time round i replaced the whole unit head and valve. The Second one (honeywell) was just the head. I noticed on the recent one there was a load of gunk that oozed from the motor onto the shaft and dried hard - like a resinous substance.

    Anyone else had bad experience with them?
  2. andy48

    andy48 Screwfix Select

    1. Remove the head.
    2. Try turning the spindle by hand. They only move through a few degrees, but you should be able to move it by hand. If not, then the valve itself is the problem.
    3. I only use Honeywell valves as I find them reliable and long lasting, generally for years or even decades.
    4. Never seen the sort of dried resinous substance you describe.
    5. I trust the valve is mounted in free air and not where it can overheat. They do run hot.
  3. Tilt

    Tilt Screwfix Select

    @Deme23 Does the valve stay warm even with the heating off ????????

    I have a newly installed boiler along with a wireless thermostat and 3 port valve / Y Plan...
    And I'm sure my valve stays warm even when the heating and water are both off... I'm doing more checks but definitely warm when the pipes were cold...
    I need to look into this more before asking my own questions and I do not wish to hi-jack your thread...
  4. Deme23

    Deme23 New Member

    The valve spindle turns without issue and the whole unit is positioned in free air. Ive bought a replacement head/body (honeywell). I'll refit the whole lot and see how it goes.
  5. Deme23

    Deme23 New Member

    I'll keep an eye on mine and let you know. - have you tried taking the casing off to see how hot the motor is? (turn off power first!) Leave the power off for a while - does it cool down?
  6. Dave does Gas

    Dave does Gas Screwfix Select

    I'd start to suspect the system water is affecting the valves, screwfix do a cheap PH testing pen might be worth getting one and taking a sample, youll be lookig for a PH value of 6.5 to 8.5, anything outside that then you'll need to start looking at causes.
    You may also want to take a low level sample for sludge
    you might find this an interesting read
    Last edited: Mar 9, 2021
  7. sam spade

    sam spade Active Member

    What you are experiencing is normal behaviour. If "CH only" is the last call, the valve is held in the CH only position by 240Vac on the grey wire. The boiler does not light as there is no longer 240V on the white wire. You can clear this by either switching HW On or turning the power off at the mains. The valve does get warm but it's only 6W, so nothing to worry about.
    Tilt likes this.
  8. Tilt

    Tilt Screwfix Select

    @sam spade .....Thanks sam...Much appreciated.

    Gives me something to try (turning HW on) as I would prefer everything to turn off, and automatically via timer...
    I know it is only a tiny amount at 6W but I would have thought the timer would have turned everything off.

    Does (or should) the timer not disconnect power to the Valve AND the Receiver (for the wireless Thermostat)?????
    I ask, as the Receiver stays live too, and clicks on and off, even though H & HW are both off???

    Thanks again.
  9. kiaora

    kiaora Guest

    As Sam says, the grey wire holds it, and the programmer is sending a ‘no hot water live’ down the grey wire,

    it’s normal for the programmer to send a live to the grey when no water is the demand,
    It’s just a querk of the system, there are ways to cancel the permanent grey live when “off”, but it’s not recommended to modify a system and risk upsetting manufacturers instructions,

    but you can, just need to add a relay,

    good luck
    Tilt likes this.
  10. sam spade

    sam spade Active Member

    The grey wire, which holds the valve open when HW is satisfied or not required, is fed from two places: programmer HW OFF or cylinder stat "satisfied". Which one is active depends on what triggered the call to turn HW Off. So the only ways of removing the voltage from the gey wire are (a) turn the power off at the mains, or (b) set a call for HW.

    A receiver needs a permanent supply, otherwise it could lose the binding to the transmitter. I don't know why the receiver clicks on and off whne CH and HW are both off.
    Tilt likes this.
  11. heatyman

    heatyman Well-Known Member

    Some programmers have a 'delatching' feature to obviate this.
    Was the gunge you noticed out of the Honeywell valve? Some of the cheaper motors leak out of the gearbox behind the spigot, but it is unusual to see this with genuine Synchron motors.
  12. Deme23

    Deme23 New Member

    Hi, yes the gunge was on the honeywell.

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