Saunier Duval Standard Effieciency 30 KW COMBI

Discussion in 'Plumbers' Talk' started by fronnie_5, Jan 9, 2009.

  1. fronnie_5

    fronnie_5 New Member

    Hi all

    Just a quick question as not really worked much with these models. Was called out the other night as the customers boiler was not working. Hr had removed radiators and filled back up.It was fault code F5. Reset the overheat stat and problem sorted. Since then customer called me back to say ,he has also been having trouble with hot water but forgot to mention it while i was there.

    When he turns hot water on it comes on for 4 secs ,water gets hot, burner goes off till water cold then fires up again and the cycle is repeated.
    Any ideas will be greatly appreciated
     
  2. mully123

    mully123 New Member

    Sounds like dhw exchanger could be scaled up,is there an in line descaler on cold feed to boiler.
     
  3. Allhours

    Allhours New Member

    I would pull of the combustion cover and see if it stays on.
     
  4. mully123

    mully123 New Member

    stays on.

    Is that not a dangerous thing to do,it might have screws.LOL
     
  5. Allhours

    Allhours New Member

    Might break a finger nail or 2, i suppose.
     
  6. fronnie_5

    fronnie_5 New Member

    Thanks for replys, will do. Dont think pulling cover off will help. It fires up and stays on for heating with no problems at all.
     
  7. Allhours

    Allhours New Member

    You dont have to take the advice,just a possible diagnosis is all.
     
  8. fronnie_5

    fronnie_5 New Member

    Did take the advice pal. Am just letting you know that the heating is working mate thats all, thanks for possible diagnosis
     
  9. Bit Of Advice

    Bit Of Advice New Member

    Why ask for advice and then say you do not think its that.

    You are asking because you do not no.

    I think what the are getting at is if it works without cover on it could be aps or venturi.

    Just cause its working in ch mode doesnt mean 100% these parts are ok.
     
  10. mully123

    mully123 New Member

    If you take the time to listen to what the OP said then you would know its got nothing whatsoever to do with the APS or Venturi,hes already told you the heating works fine.The boiler on DHW is cutting out,which indicates a blocked or partial blocked heat xchanger,nothing to with ignition sequence ***.
     
  11. fooman

    fooman New Member

    perhaps the diverter valve diaphram is split. I had this on a worcester 24cdi
     
  12. Bit Of Advice

    Bit Of Advice New Member

    Getting a bit hot under the collar are we?
     
  13. Bit Of Advice

    Bit Of Advice New Member

    Can't see how the diaphragm would give them symptons but i could be wrong.
     
  14. fooman

    fooman New Member

    the micro switch on the end of the diverter valve fires the boiler up.
     
  15. Bit Of Advice

    Bit Of Advice New Member

    Yes but the boiler is firing but going off which indicates the diaphragm is pushing and making the microswitch.

    It does seem like a scaled up heat ex or thermistor problem if it has em.

    As it's not locking out, the boiler is sensing the water is at temp and shutting burner off.
     
  16. fooman

    fooman New Member

    well when the diverter valve went on my boiler on the hot water side it kept going on and off every 10 secs or so. The diaphram was letting water past then there was not enough pressure to make the mircoswitch.
     
  17. Bit Of Advice

    Bit Of Advice New Member

    Oh right = that is worth reading for me, something to bear in mind whilst on a job with these symptoms.
     
  18. Bit Of Advice

    Bit Of Advice New Member

    I suppose this guy needs to no if the microswitch is being permanently made whilst the demand is on - to rule out this fault.
     
  19. mully123

    mully123 New Member

    Listen Fooman,the OP was called out originally because the Boiler had gone to OVERHEAT,runs for a few seconds then switches off,cools down and then switches back on.Why would it go to overheat,whats that got to do with a diverter?
     
  20. fooman

    fooman New Member

    same as if you read the OP's posting he said that fault had been sorted and now he has problems with his hot water. NO LONGER HAS ANY PROBLEMS WITH THE HEATING !!!


    so be a good lad and have another read ;)
     

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