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baxi 105 he fan/flue fault

Discussion in 'Plumbing and Central Heating' started by willroy, 29 May 2008.

  1. willroy

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    HI first post here goes.House is currently unoccupied .Boiler was serviced and was working ok.Turned preheat off on hw as nobody was staying in the house.Anyway turned tap on a few weeks later no hot water.Tried heating same.Went to boiler noticed when heat was being asked for by either tap or radiators the 50 degree light would flash meaning fan/flue fault.The boiler is approx 3 years old and hasn't missed a beat till now.Looked at various posts regarding this fault and can't make my mind up what to look for.When heat is asked for the fan above spins up then after a few seconds the fault appears.

    thanks :(
     
  2. Agile

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    Could be a faulty PCB.

    But it could also be a fan/flue/APS problem but all of those aspects should be investigated by a competent CORGI engineer.

    Tony
     
  3. willroy

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    Thought about the aps but most common seems the pcb replacement for a new one.
     
  4. Agile

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    A competent boiler engineer diagnoses the actual fault rather than changing an expensive part "because they sometimes fail".
     
  5. willroy

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    easier said than done where i live .I am a mechanical /electrical engineer by trade .Can diagnose most faults in my line as i have an abundance of spare parts.I know a few plumbers /so called engineers who have come out to boilers before with no luck costing friends a fortune.Thanks anyway for your help will check aps switch is switching first if ok will check pcb relays
     
  6. Agile

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    Merely finding a fault by repetitively changing parts is not really "diagnosing" the fault.

    We call them "parts changers". They are mostly employed people as independents cannot afford to change expensive parts in case they are not the problem!

    Tony
     
  7. willroy

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    I understand where your coming from but decent boiler enginneers where i live are like rocking horse ****.
     
  8. LUNAT

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    HI


    APS faulty= common fault on these boilers.
     
  9. willroy

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    If i short the terminals to make a circuit should pinpoint fault ie if boiler fires up aps switch if not something on pcb
     
  10. Trouble666

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    If the fans running and the boiler then goes to lockout, I would suspect a faulty APS myself; But again, like someone said in this thread earlier, a competent engineer would use a multimeter to diagnose through faultfinding-

    If your going to chuck parts chuck an APS before chucking a PCB!
     
  11. willroy

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    Had a good look at it today.checked out aps looked ok.Has a common supply with normally open and normally closed contacts.Power was going to aps but didn't look like it was switching when fan gets to full speed.Checked with meter when fan at full speed hey presto boiler lights up .Removed meter boiler shuts down.Faulty aps switch i hope .getting new one tomorrow
     
  12. willroy

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    fitted new aps today working great.Thanks for all your help
     

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