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Worcester 18Ri pump overrun issue

Discussion in 'Plumbing and Central Heating' started by rwilko78, 4 Jun 2014.

  1. rwilko78

    rwilko78

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    Hi, I've noticed that the pump overrun on my worcester 18ri does not stop after demand has been reached on the hot water circuit, the pump in the airing cupboard continues indefinitely. If I call for demand on the heating circuit and then turn the room stat down the pump overrun operates for the specified 2 minutes once the boiler has ceased firing and the pump stops fine. I have a sealed system. Any ideas why the pump overrun works correctly for the heating circuit but not the hot water circuit?

    Thanks
     
  2. Agile

    Agile

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    I suspect that the cylinder stat is not being satisfied!

    It should be set at 60 C and that means the boiler needs to be at 70 C when heating the hot water.

    After checking the cyl stat is correctly set then try turning the boiler flow temp up to 70 C. You will only know this if you can measure the flow temp with a contact thermometer though!

    Tony
     
  3. gaspro1981

    gaspro1981

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    3 port or 2 port valves ?
     
  4. rwilko78

    rwilko78

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    Both valves are 2 port, one is Drayton the other Honeywell

    Thanks Tony - I tried turning down the cylinder stat but the pump carries on running. Only seems to stop if I run the heating for a bit then shut off demand
     
  5. gaspro1981

    gaspro1981

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    Just the pump runs and nothing else ? Boiler
    Not firing ?
     
  6. rwilko78

    rwilko78

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    No just the pump, demand for the boiler has stopped, the green ignition light extinguishes but the pump carries on forever - only if the last call for demand was hot water
     
  7. gaspro1981

    gaspro1981

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    You need to be checking the voltages on the live return connection (LR)
    on the boiler Pcb only do this if you have the necessary equipment and can work safely and competently
    Do not remove the boiler cover as this is part of its casing and if compromised can cause serious complications.
    You will be able to determine the LR voltage in the wiring center/station if you can identify the correct cable or flex.
     
  8. McCombi

    McCombi

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    Doesn't the case have to be removed on a ri to access the wiring :confused:

    Oops never saw last bit you posted. Sorry
     
  9. Agile

    Agile

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    Are you sure the pump is correctly wired directly back to the boiler pump connections?

    Tony
     
  10. DIYnot Local

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