Replacing Central Heating Diverter Valve?

Discussion in 'Plumbing and Central Heating' started by smarty, 13 Feb 2007.

  1. smarty

    smarty

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    After reading the excellent sticky on here it appears that my reason for having only hot water and no heating is that the diverter valve is faulty on my system. It is an old system compromising a Thorn Emi back boiler, cold water header tank, hot water tank, I think the hot water is gravity fed and the heating is obviously pumped, the pump is working fine. I put the diverter valve in manual and my heating started working again. The valve is Honeywell Sundial Y Plan 3 position divertor valve (so it says on the metal cover anyway). The motor on top of the valve is a synchron motor. It has some digits on the top but I cannot read them for bad access, although I could get a mirror or something. I was just wondering is this motor all I ask for at a plumbers merchant, as the sticky mentions that the Synchron motor is widely sold in DIY sheds. Or am I much better off getting the number somehow. I would like to try and just replace the actuator as mentioned in the sticky, as replacing the whole lot would probably be major grief and require a plumber. Although I will if the valve is leaking as the sticky mentions.

    If there's a little bump on the top of the motorised valve head (only for Honeywell valves), it means you can remove the head (actuator) from the body to replace it without getting wet. The mechanics of the heads do wear out and jam, but you can just change the motor. (Synchron motor is sold widely, even in diy sheds).

    Sometimes it's easier to take the head off to get it into an easier position for you to fiddle with the two wires to change the motor, then put the head back when done.
    You can use an ordinary flat bladed screwdriver for the motor and head screws, but for the fairly recent ones a magnetic T15 Torx screwdriver works better.

    If you change the motor with the head off, wiggle the lever to help seat the motor .

    If you notice any moisture leaking from the valve body shaft, it probably will have got into the head and rusted it, and possibly the switche(s) as well. You need a whole new valve, and that means draining the system.

    Isolate the mains power from the heating system before you start any work.


    Any help please?
     
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  3. stem

    stem

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    Here's a link to one. Those I've seen all use the same motor. I would be inclined to replace the whole head though, because if the motor has failed the valve is probably getting on a bit and the machanism and microswitches will be too.

    http://www.screwfix.com/app/sfd/cat/pro.jsp?id=28670&ts=43439

    You could take the old motor out and put a plug (with a 3A fuse) on the wires to test it. Sometimes the valve mechanism jams and the motor's actually OK. If the motor doesn't work when you test it, then take it along to the plumbers merchant and show them what you want. If it does work start looking elsewhere.
     
  4. smarty

    smarty

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    Sorry for being a numpty but can I replace the head without getting wet? I am not sure how these valves work, is the head the motor and some kind of actuator, or is it the actual valve internals too? As obviously if it is the valve internals too I will need to de-pressurise the system as there are no isolation valves. Thanks for the link to the motor though :)
     
  5. Agile

    Agile

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    This is amazing!!! You have already posted the answer to your own question !!! See below as copied from your first posting!


     
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  7. nickso

    nickso

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    i cant believe you are contemplating changing the head if the only fault is the motor. have a look inside and see if the spindle has leaked....if it hasnt, get a synchron motor and change....job done.

    dont waste your money on a head you probably dont need.
     
  8. smarty

    smarty

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    Sorry Agile it just not that clear to me as I have not a clue about this type of valve. I take it to see this bump the syncron motor has to be removed first as it is not a bump on the motor itself?

    Thanks Nikso I may try just replacing the motor. My logic behind changing the head was that the system is the best part of 20 years old so I thought to try and replace as much as possible. But as you can tell I am not that clued up on this type of valve so I did not know what has failed, or what is prone to failure. But the motors do seem very cheap so I guess not much lost if it doesn't fix the fault ;)
     
  9. nickso

    nickso

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    no the bump is on the cover itself.

    http://www.plumbworld.co.uk/762-1363


    the little round bump on the right of the valve cover
     
  10. smarty

    smarty

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    Cheers Nikso that is much clearer now, I shall check it out. But probably just try a motor first. Cheers :D
     
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