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Worcester Bosch 40CDI Regular Boiler Fault Please Help!

Discussion in 'Plumbing and Central Heating' started by PaulElliott, 20 Jan 2010.

  1. PaulElliott

    PaulElliott

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    I have recently had re-occuring problem with a Worcester Bosch 40CDI boiler that has been installed for over one year.

    The system has worked fine up until now and the boiler has been installed on a new system that was flushed after install with scale inhibitor in the system.

    The boiler displays a fault code saying that the boilers heat exchanger is heating up too quickly. Worcester have been out and changed the heat exchanger, I have flushed the boiler and connecting pipework out twice in two weeks and I'm sure there is no restriction in the pipes. I have also replaced the pump for new, Grundfos 15/50 which is working fine. But I'm still getting the fault.

    The boiler is fitted to a 250L thermal store that heats CH and DHW so the return temperature on the boiler is cool but it constantly overheats.

    Any ideas?? I'm running out of them and need to sort this ASAP.

    Worcester are saying it's nothing to do with the boiler, it's a blockage or the pump is faulty. It will be unlikely to be a blockage on a new system (but perhaps it is and the flushing pumps aren't getting out the blockage) and Grunfos pump is new.

    Has anyone had any experience with this fault before??
     
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  3. Ericaridley

    Ericaridley

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    I am interested to find out if you have resolved this. We have the same boiler and similar problems. It was a new build house. Full install, ran for two years fine then everything has been replaced and it still will not work. Bosch say it's not the boiler, it's the install. We are struggling to get the temperature in the house as it's knocking off every few minutes. My email address is Erica@ericaridley.orangehome.co.uk. Would it be at all possible for you to let me have a number to ring you re this.

    Our only alternative at the moment is to move out and pull our house to pieces, which would be devastating.

    Thank you
    Erica
     
  4. boilerdoktor

    boilerdoktor

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    i have heard of this and what happens is software on the pcb notices when temps rise or fall too fast and it blocks out the burner and hovers between 45degrees to 53 or 54. Usually happens in large properties where there is large cylinders/underfloor heating. I've been told that they can fit a new pcb which hasn't got this software on. Is this what is happening to yours?? If they changed heat ex then i imagine it is not and it is overheating!(which could well be your system/setup!)

    If its in warranty still maybe see if worcester will send out a senior tech engineer to have a look! Their diagnostics are very good at watching temp rises etc!

    hope this helps!
     
  5. rosiew

    rosiew

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    should the pump be a 15-60?
     
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  6. picasso

    picasso

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    22mm pipe off the top of the boiler , 3 port valve and boiler still set on full output ?
     
  7. Tibbot

    Tibbot

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    25-50 with F/R min 28mm, preferably 35mm to first junction.
     
  8. Ericaridley

    Ericaridley

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    Worcester Greenstar 40cdi Convention boiler in a large 6 bedroom house and using a 200 litre megaflow tank for my hot water, my house is split into two zones left and right.
    The problem what I have is that when it fires up it only stays on for 15 seconds and puts the fault code as follows: it is two right angles adjacent to each other which flash off and on, this is the meaning of them

    The display shows alternatively the CH flow temperature and . The
    gradient limitation is active. The primary temperature is rising too
    fast and the burner has switched off for 2 minutes. See error E9.

    The next fault is E9 which is: safety temp limiter in flow has tripped.
    The next fault is like two lower case t back to back which meaning is:

    The display shows alternatively the CH flow temperature and . The
    Syphon-fill programme is active. Seeservice function 4.F

    There is no particular order for these codes, could there be a blockage in the system it had a new pump on 6 months ago
     
  9. picasso

    picasso

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    there are two pipes coming off the top of the boiler, can you tell what size they are ?
     
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  11. Ericaridley

    Ericaridley

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    There are 3. Two 90mm pipes and a 70mm pipe
     
  12. picasso

    picasso

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    sorry I didint make it clearer, I meant the 2 copper pipes on the left hand side.
     
  13. Ericaridley

    Ericaridley

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    A flow, return and a bypass
     
  14. picasso

    picasso

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    Any chance of a picture ?
     
  15. Ericaridley

    Ericaridley

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    The two on the left hand side are both 90mm copper pipes. Are they the ones you mean? Sorry to be vague
     
  16. Ericaridley

    Ericaridley

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    They are classed as 28mm. Sorry for the confusion
     
  17. Ericaridley

    Ericaridley

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