Worcester Highflow 400 Electronic RSF

Discussion in 'Plumbing and Central Heating' started by ktnabd, 7 Oct 2017.

  1. ktnabd

    ktnabd

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    Folks,
    Moved to new property about two years ago, where we have Worcester Highflow 400 Electronic RSF (originally installed ~2002) and looks there are some issues and was wondering if any experts around and able to check in Aberdeen/Aberdeenshire area.

    Here's what's happening...

    * Started having intermittent hot water being cold since about 1 month (usually first thing morning cold shower and randomly) and later on the day would get normal or few times sorted by re-set through CH/HW dials but don't know what was actually triggering system/HW failed and back to normal and no usual indication on LEDs.
    * But wouldn't get HW started in this morning...
    * When tried switching on CH - looked ok and heated up radiators fine.
    * Notice when HW is running (when it works) - CH out pipe at back of the boiler heats up too (radiator doesn't get hot though)..when CH/HW is off, after 15min/30min that CH out back to normal/no hot... that sounds odd, may be something to do with diverter valve??
    * Checked few things and notice pressure gauge was reading zero, and low pressure, re-fill through the loop, switched on CH for some time etc. This did not sort the HW problem ... so tried to reset through temp dial controller, and seems that made HW running fine (but still CH pipe back at boiler gets hot).
    * Checked the schrader valve and notice water coming out. So as suspected diaphragm in expansion vessel perished and that's where pressure may be was lost initially. So surely needs expansion vessel replaced...
    * but same time wondered switching CH did not trigger relief valve or pressure remained ~1.5 bar (at cold ~1 bar)...so checked all radiators and notice some were bit cold at top so think there is plenty air in the system and may be that's why relief valve was ok and instead radiator air may be compressed.
    * Noticing some of the radiators are cold at the bottom...doesn't affect much to worm up the house but know something isn't right.

    Appreciate any help or if any folks have seen any similar symptoms?

    Cheers.
     
    Last edited: 7 Oct 2017
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  3. ktnabd

    ktnabd

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    Thinking to replace expansion vessel and treat/clean the system via Sentinel x400, any experience on that?
     
  4. McCombi

    McCombi

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    Most likely problem is relating to a mixture of plate heat exchanger dirty, and bypass pipe behind diverter motor choked.

    Horrible job to fix in my opinion.

    Be better getting a fixed price repair off worcester if they still do them on these.
     
  5. ktnabd

    ktnabd

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    suppose HE and bypass would make this problem intermittent? - as since y'day HW is running fine (but still CH pipe behind boiler get bit hot while HW is running) - presume only way to know if by taking stuff off...unless there is any way things can be checked w/o taking parts apart?
     
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  7. McCombi

    McCombi

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    Could be a number of things tbh. Difficult without seeing it.

    Sounds like div valve maybe not sending all heat to plate heat ex and some passing to ch system but hard to check as if I recall, these things dump heat into ch circuit via pump overrun after a dhw demand anyway.

    As said, best to get a fixed price repair on it as very time consuming and lots of bits may be required to fix.
     
  8. AGAS

    AGAS

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    how much water ? because some water comes out doesn't mean the diaphragm if fooked
     
  9. ktnabd

    ktnabd

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    @AGAS , didn't check schrader valve fully - pressed for very brief and notice water out of it. Only logical reason for pressure loss thought to be EV, and didn't notice relief valve cracking..
     
  10. ktnabd

    ktnabd

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    if that's the case and heat is being dumped to CH circuit than maybe make sense as only noticing small section of CH out pipe at back of boiler gets hot and no sign of hot radiator. so that's may be good sign.

    thanks and ok shall try to see if Worcester able to help or still doing fixed price repair...

    if EV is gone than would need to replace irrespective of above intermittent HW issues...


    may be planning to drain CH system and see what/how much of gunk comes out and treat with Sentinal X400 and if that improves overall situation - you guys think there is any mileage doing that?
    If draining system - would end up checking/replacing EV at the same time.
     
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