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Discuss Boiler making noise and not staying on in the Plumbing Forum area at

  1. Steveuk

    Steveuk Member


    I have an Ideal ICOS boiler in my house for HW and CH. It has been working fine but I have noticed that upstarts in my immersion heater cupboard that it has been a little noisy and hear water running, haven't really noticed it before. Anyway, last few days I have noticed some bangs coming from my boiler. I can't pin point WHEN it happens. I have just been playing with it and cant seem to recreate it.

    During my testing (with no really knowledge of boilers) I found the following.

    I turned OFF the HW and CH via the Hive control.
    - Boiler status turned to '0'

    I then turned both HW and CH to ON
    - Boiler turned to 'C' and flashing 'lit light' for about 10 minutes.
    - Fan then started, I heard the boiler ignite and light went solid.
    - Within 10 seconds the fan started to slow down, there was a click and the flame went out (well sounded like it) the fan slowed down further until it stopped and the light went back to flashing.

    It has done the same cycle every 10 minutes 3 times now, but on this last one after it turned off the light is no longer flashing. there are no error codes showing on the front, just 'C'

    Any ideas on what this is?

    If it makes any difference upstairs in the immersion road the tank feels hot along with the pipes that are going to it and the circulation pump is running. I am still getting hot water to the taps somehow but cold radiators.

    Would I be right in thinking that the boiler is not heating the water and the immersion has automatically come on but only heating the HW? I obviously cant tell you how long the CH has or hasn't been working as its been so warm it hasn't been on.

    Any advice welcome. Thanks, Steve

    Ok, so I went upstairs to the immersion cupboard and turned the HW and CH OFF from the Hive and the circulation pump stopped. Is that normal or could that be an indicator for something?
    Last edited: Jun 8, 2019
  2. Steveuk

    Steveuk Member

  3. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Your immersion could be switched on but it won't have been automatic. I've lost count how many times I've worked on systems where the immersions are just left on permanently with the customer not having a clue it was on.
    When the hot water and heating are turned off, the pump should stop. Not straight away though as it should have pump overrun.
    From what your describing my initial thought is poor circulation. What's causing it could be a couple of factors though. I could also be wrong so, I think the best thing you can do is to get an engineer in to check your system over.
  4. Steveuk

    Steveuk Member

    Yes there is an immersion switch but that is off. And yes the pump turned off when the CH and HT was turned off. I just don't understand what's heating the water for the HW if the boiler keeps turning off every time it turns on. :-/

    I am going to get someone in, just thought id see if I could figure out what it was if it was going to be an easy fix.
  5. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    Well the boilers heating your hot water. When the display shows C that's showing your boiler is working.
  6. Steveuk

    Steveuk Member

    The manual says that 'C' is "Boiler is active for central heating" but I guess it means just active for heating because it comes up with this when I turn on just the HW.

    I have just tried to boost the HW by itself. It came on, lit and whilst I was upstairs looking at the immersion heater (2 minutes max) I came back down and it had switched off and was back to status light flashing and 'C' displayed on the front. It waiting about 2 minutes and relit but then there was 5 or 6 bangs (almost sounded like a flame almost being blown out but much louder) then it switched off again.
  7. Craig Watson

    Craig Watson Plumber GSR Top Contributor!!

    C just means on for both heating and hot water. The 5 or 6 bangs you heard could be the boiler over heating. It then shuts down until the water cools then fires back up again and so on and so on.
  8. Steveuk

    Steveuk Member

    That could well be it. The first time it shut off (without the bangs) it relit within about 3 minutes, after the bangs it was more like 10.

    Im going t get someone in to service it and hopefully he'll solve it. Thanks.
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