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Sime boiler problems

Discussion in 'Plumbing and Central Heating' started by mwillmroe, 13 Mar 2009.

  1. mwillmroe

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    I am having problems with my sime combi boiler.
    When ever I run hot water for more then five minutes, the pressure drops and the pilot light goes out.
    However the pilot light does not go out if you have the hot water running and the central heating running at the same time.
    I keep having to pump up the pressure on the boiler, but the pressure still drops?
    Any ideas what the problem could be?

    Many Thanks
    M Willmore
     
  2. Agile

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    Everyone has problems with Sime boilers. They are not very friendly.

    Its a slightly odd symptom you have and I suspect there are two faults.

    However, it would be easier for us to do our guesses if you could tell us the exact model.

    Tony
     
  3. gas4you

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    Strange one, but from your post, it must be pointed out that you cannot have DHW and CH running together. A combi is either or.

    I would 'guess' that if you think the ch is running as well, then the boiler has switched back from HW but as ch is on it is still heating the water somehow :confused:
     
  4. mwillmroe

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    The boiler is a sime friendly (i feel they could have chosen a better name).
    Sorry if I wasn't very clear in my message, If I have the thermostat up high for the central heating and the hot water running I don't get the problem. But if I have the thermostat right down and the hot water running I do get the problem.

    Many Thanks
    Mark
     
  5. Agile

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    Its still difficult to understand what you are trying to explain.

    Please turn OFF the central heating..

    Then see if the boiler fires up and provides hot water.

    Then tell us!

    I did say they are not very friendly!

    Tony
     
  6. kev25v6

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    Ive got the same boiler and had a similar problem with the pilot cutting out. When running the hot water it would run hot for a while then cold then hot again. When the tap was turned off the pilot would then turn off unless the CH was turned to on for when it switched back from HW to CH. Ive had new thermocouples, main board, thermisters fitted and no real difference until i had a new pump fitted and its been excellent ever since. It did help to turn the temp of the water dial down to about half and run the tap slower to keep the water hot enough while the problem was being sorted. There are a lot of things on these boilers that go wrong, ive had mine virtually rebuilt with new parts in the last three years.Mine is generally around 1.5 bar, rising to just under 2 bar when heating is on full.Never drops below what it was set at when cold though.I think a big drop in pressure means a leak somewhere.
     
  7. mwillmroe

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    Kev,
    That is exactly the same problem I am having. Do you know how much it cost you to get the pump replaced?

    Thanks,
    Mark
     
  8. Slugbabydotcom

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    Its not often we see Tony in 'make a joke' format














    :oops:


    Sorry I just couldn't resist :oops:
     
  9. Agile

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    If you look hard enough you can see at least one a day but many are read without being noticed!

    I dont think the OP noticed that one.

    Its hardly worth me bothering.
     
  10. Agile

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  11. kev25v6

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    New pump fitted was 120 quid all in. The original Sime pump as a whole is no longer made but an Ideal mp63h pump head fits onto the body of the existing pump, grunfos heads don't fit, they are slightly different.Can't say for sure it will fix yours but it was the last thing fitted to mine and the only thing that made it work ok. Its made the shower a lot more powerful too, so the old one must have been playing up for a while before it seized.
     
  12. pam123

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  13. Agile

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    I dont know why Pam has quoted a posting from two years ago for no obvious reason!
     

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