Central Heating Problem

Discussion in 'Engineers' Talk' started by Lenny Lalwey, Jan 3, 2020.

  1. Lenny Lalwey

    Lenny Lalwey New Member

    Hi
    Is there anyone out there who can help me?
    I have, for the last 3 years have an intermittent problem with the central heating boiler, which has just started again.
    With the heating programme set to "on" for hot water & heating and the room thermostat turned up, I can only get the boiler to come on if I turn up the settings on the frost thermostat.
    Hope you experts have the answer and...
    A VERY HAPPY NEW YEAR TO ALL YOU GUYS
    Lenny
     
    Last edited: Jan 3, 2020
  2. Heat

    Heat Screwfix Select

    Your programmer could be faulty and not putting live to boiler.
    Or you might have motorised (zone) valves not putting live to boiler.
    Unlikely to be room stat faulty if hot water also fails to work
     
  3. Lenny Lalwey

    Lenny Lalwey New Member

    Hi
    Thanks for this, I can confirm that this fault is only affecting the central heating. The heating of water is working as it should.
    Also I changed the programmer for a new one only last year.
    Could you explain more about the motorised zone valves as I am not sure what this is.
    Many thanks Lenny
     
  4. terrymac

    terrymac Screwfix Select

    Motorised valves are to be found on your pipework ,usually close to the hot water cylinder. Squarish shaped box ,mounted on pipework,with electric cable trailing from it. Take some pics around cylinder and post here.
     
  5. Severntrent

    Severntrent Screwfix Select

  6. Lenny Lalwey

    Lenny Lalwey New Member

    Ok Thanks "Severntrent" for the link...Now I know what you are all talking about.
    The system has a 3 port mid position valve which I changed last year (dec) because it was leaking. I replaced it with a Honeywell brand complete with the electronic actuator head.(told Honeywell is better than Corgi) I feel I must mention, that the actuator head I have changed 4 times for new ones in the last 5 years, as I was always being told that the actuator was causing the fault.
    In the last 3 years, I have changed just about everything, circulation pump (New, like for like) 2 years ago. Frost stat and hot water cylinder stat 3 years ago (new Honeywell). Programmer (New, like for like) last year.
    In fact, the only thing I haven't changed which is 20+ years old, is the room stat as I'm told this is working as it should be.
    The oil feed boiler unit is 7 years old and the last & only professional full service was carried out last Nov (2019) Where the oil line was changed and the nozzle was also replaced as "standard practice". Apart from a dam good clean, no other issues were found.
    All your input is very much appreciated and I really hope someone can put me on the right road to end this really annoying problem because I am now at a complete loss!
    Don't know if its makes any difference, the boiler, 3 way valve, pump and frost stat are situated in the garage and the hot water cylinder is in the 2nd floor bathroom just above the garage.
     
    Last edited: Jan 3, 2020
  7. Mike83

    Mike83 Screwfix Select

    If the frost stat brings on the heating then the 3 port is probably working ok.
    The frost stat is probably wired in parallel to the room stat.
    Have you tried testing the room stat or linking it out.
     
  8. Severntrent

    Severntrent Screwfix Select

    Put photo of room stat up and I'm sure someone will be able to tell you how to bypass thermostat signal so it calls for boiler to fire up
     
  9. Lenny Lalwey

    Lenny Lalwey New Member

    Many thanks for your reply. No I haven't tried testing or linking the stat out, as i am not sure how to do this
     
  10. Mike83

    Mike83 Screwfix Select

    What make of wall thermostat do you have?
    Do you know how to remove the cover from it?
     
  11. Lenny Lalwey

    Lenny Lalwey New Member

    Thanks again Severntrent for your time. Ive taken a photo, but just thought, do you want the photo to show the wiring?
    Also I do have a replacement room stat, which is a Honeywell T6360. When I purchased it, was told its a "direct replacement for my Satchwell one" but the wiring connections are different. Room Stat old.jpg Room Stat old.jpg
     
  12. Lenny Lalwey

    Lenny Lalwey New Member

    Yes and its a Satchwell TLX
     
  13. Mike83

    Mike83 Screwfix Select

    That certainly looks like an oldie.
    Show is a pic with the cover removed.
    If you then link the wires and the heating works as normal from the programmer then it’s the stat.
    Or you can just replace it.
     
    Lenny Lalwey likes this.
  14. Lenny Lalwey

    Lenny Lalwey New Member

    I've just been called away, so will not be here for a couple of hours ....... Sorry
     
  15. Lenny Lalwey

    Lenny Lalwey New Member

    Many Thanks Mike83 I will do as you ask, but I been called away. So its going to be a couple of hours before I can get back.....sorry
     
  16. Lenny Lalwey

    Lenny Lalwey New Member

    Ok, here the wiring photo for the room stat.
    Sorry for the delay.
     

    Attached Files:

  17. Mike83

    Mike83 Screwfix Select

    So you can either pop the red and yellow in the same terminal or just change the stat.
     
  18. Lenny Lalwey

    Lenny Lalwey New Member

    Hi Mike83 That was a very quick reply Thank you
    Linking the red & yellow together will do what, over ride the room stat?
     
  19. Mike83

    Mike83 Screwfix Select

    Yes it will over ride it
     
  20. Lenny Lalwey

    Lenny Lalwey New Member

    Ok Thanks I will try this out today and see if the boiler fires, if it does then I will see about changing the room stat.
    Will get back to you with the results later, may be tomorrow.
     

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