Glow worm Energy 25S issue

Discussion in 'Plumbers' Talk' started by Bazooka, Jun 1, 2018.

  1. Bazooka

    Bazooka New Member

    Hi, I've decided to post here as I'm having problem with finding out what is wrong with my boiler.
    I'll try to explain setup
    Boiler is located in the garage,
    Hot water tank is lo aged in the loft
    Programmer Honeywell ST699 is in airing cupboard
    One room thermostat Honeywell T6360B is in the house set to 10degrees
    One room thermostat Honeywell T6360B is in the garage, turns down to lowest setting.
    There are 2 valves Honeywell 272848 on pipework in the loft
    The issue:
    Boiler fires up even when heating and hot water is switched off. Approx every 10 minutes. For those familiar with the boiler the radiator icon on the display is always flashing indicating demand regardless of the programmer or thrrmother seting.
    The question:
    What can be the cause and what would be the easiest way to diagnose it.
    Many thanks in advance for any help
  2. Dave does Gas

    Dave does Gas Well-Known Member

    Zone valve could be sticking sending a switch live signal to the boiler, on the valves there is a small lever, give it a wiggle it might free up some of the switching inside the actuator. Do the heating valve first. You may also have an electrical fault with the programmer or the room stat. Hard to diagnose without being onsite with a multimeter.
  3. Mike83

    Mike83 Well-Known Member

    I would go for a faulty zone valve (switch inside actuator).
    As it's an s plan system I don't think the programmer or room stat would be at fault.
    If the programmer was faulty the room/cyl stat would still kick in turning the boiler off.
    Also if the room stat did stick on, turning the programmer off would kill the power to it.

    A multimeter will confirm that the switch in the actuator is faulty.

    Don't post this issue in the sparks forum, it will probably cause an argument between members.
  4. Bazooka

    Bazooka New Member

    Just looked at the valves, not sure if it is important:. It's a new system in a new build house and one of the valves is made in 2013 and looks old. Not sure how to test microswitches on valves. I moved the lever on both valves but see no difference. Not sure which is hot water which is heating. I've attached a photo, One on top of the tank is made in 2013. One on the front is new made in 2018
    Forgot to add that I have multimeter. Should I test it for continuity?

    Attached Files:

  5. Mike83

    Mike83 Well-Known Member

    Top valve is hw.
    Lower one heating.
    Only proceed with testing the electrics if you feel competent to do so.
  6. Bazooka

    Bazooka New Member

    I've decided that I'm leaving it to the developer and plumber that installed it.
    I'll ask them to investigate the valve
  7. Bazooka

    Bazooka New Member

    Just to follow up on the matter. It's been fixed. Electrician forgot to remove the link in RT as boiler is using external controls. He showed me the red wire, I found video on YouTube explaining what it was. Took some time but now it works as it should.

    Now to second part.
    As it is now working as it should I would like to upgrade programmer (Honeywell ST699) and room thermostat (Honeywell T6360B) to something smart so I do not have to remember about switching it off manually. I was thinking about Nest as they offer professional installation at reasonable price but I'm not sure it will be compatible with this setup where one of the room stats is wired directly in to boiler and is located in the garage. If Nest is not compatible or there are better solutions what would you recommend? Thanks for advice.

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