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Vaillant ecoTEC plus 831 - intermittent electric fault

Discussion in 'Plumbing and Central Heating' started by Robstoke73, 31 Jan 2016.

  1. Robstoke73

    Robstoke73

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    Hi,

    I'm after some advice about what appears to be an electrical fault on my boiler which is affecting the heating operation.

    When the system is on and the room stat is calling for heat the system will stay stuck in s.30. As far as I can tell the fault is not with the stat but somewhere in the electrics on the boiler.

    I had the system serviced this week and the engineer said it was working fine. I explained the problem but he said he was not qualified to look at the electrics.

    The problem seems to occur when the system is warm. It comes on with the timer and heats for maybe half an hour before going off. I've gone into the diagnostics and seen the d.8 value flick between 1 and 0 causing the boiler to stop and start.

    If this is a fault on the PCB is it likely that an electrician can fix it or will it require a replacement? How do I find a gas engineer that is able to do the electrics?

    Many thanks for any advice.

    Rob
     
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  3. The831Bunny

    The831Bunny

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    What controls have you got? Sounds very much like those rather than the boiler.
     
  4. Robstoke73

    Robstoke73

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    Thanks Bunny.

    It's a Danfoss rf stat and receiver. Light on the receiver stays on to indicate call for heat.

    I have tried disconnecting it and putting a wire across terminals 3 and 4 but was getting the same result.
     
  5. The831Bunny

    The831Bunny

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    If D.8 was intermittently showing 0/1 with a link between T3 & T4 then the PCB needs replacing I'm afraid. D.8 will show 1 permanently with a link.
     
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  7. Robstoke73

    Robstoke73

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    Thanks. That's what I was afraid of.

    Am I right in thinking they are £200+ to replace?
     
  8. Agile

    Agile

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    That's about the price.

    But should also be fitted by a gas reg engineer as they are inside the front cover which you should not be removing s a DIYer as the case forms part of the room sealed aspect of the boiler which make it safe.

    Tony
     
  9. The831Bunny

    The831Bunny

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    That's fair enough Tony, but more so the fact that as the PCB dictates the combustion and safety sequences of the boiler these need to be tested and/or adjusted as per regulation 26/9.
     
  10. Bunnyman

    Bunnyman

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    Listen to 831 pls the other is just guessing
     
  11. DIYnot Local

    DIYnot Local

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