Oil boiler lockout - could it be fuel starvation?

Discussion in 'Plumbing and Central Heating' started by tweakie, 18 Sep 2016.

  1. tweakie

    tweakie

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    We have a Worcester Bosch Danesmoor 20/25 oil boiler that's quite old but has been OK for the 6 years we have lived here. It has on occasion gone into idle mode which I have sorted by pressing the solenoid. However when I tried to turn on the heating a few weeks ago it just locked out after a few minutes andwhen I attempted to reset it the same thing happened continually. The following have been replaced, checked, cleaned but the problem persists:



    - replaced thesolenoid, photocell, transformer, burner nozzle and bled the oilpipe, cleaned the filters and the combustion chamber


    and all to no availas exactly the same thing is happening, the boiler fires up and thenlocks out after a few minutes. There is a clicking sound (about 8-10 clicks) before lockout occurs.


    Has anyone experienced this or have any other potential avenues to explore?


    It's getting colderup here in Yorkshire and the missus is becoming somewhat impatient!
     
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  3. Agile

    Agile

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    You seem to have blindly replaced a lot of parts.

    You dont mention professional servicing, that makes me think you don't get it serviced which is why you don't seem to have considered what most people would do with a faulty boiler to call an engineer.
     
  4. Burnerman

    Burnerman

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    It would sound like the burner is igniting then failing as a sequence.....hence the clicking you hear from the control box.
    Can you ensure the photocell is actually seeing the flame.....no igniter cables in the way or whatever?
    At this stage it's necessary to have the fuel pressure checked and naturally enough, an analysis of the exhaust gases after that.
    Have you cleaned the internal flue ways of the boiler at all?
    John :)
     
  5. oilhead

    oilhead

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    John is spot on. You are getting re-ignition, then lock out. There may be a problem with the control box which is just about the only component you've not changed, apart from the oil pump.
     
  6. Terrywookfit

    Terrywookfit

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    Fookin cold in Yorkshire... It's 24c today.!!
     
  7. oilboffin

    oilboffin

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    First check oil is getting to burner also check fire valve hasn't operated or failed if it fails it's failsafe
    and shuts off if it has you can check by tying it up very temporary once oil is through check oil pressure at pump needs to be 115/120 if ok check nozzle and photo cell nozzle could be firing
    Off centre and cell not seeing light
     
  8. Terrywookfit

    Terrywookfit

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    I can understand "Glaswegian" but I'm fooked by the "Isle of Lewis" translation !!
     
  9. oilboffin

    oilboffin

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    Sorry my friend prob my typing I'm not the best
     
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  11. tweakie

    tweakie

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    Thanks guys for the helpful comments. I checked the pressure and it's correct at 105 psi and the photocell has a clear view of the flame. The pressure gauge showed that after about 2 minutes the pressure suddenly disappears and the burner re-attempts to ignite what is now presumably a nozzle starved of oil. Lockout follows and i'm left still scratching my head. Any more thoughts - why would the oil pump pressure always drop around about 2 minutes...? Cheers, Phil.
     
  12. oilboffin

    oilboffin

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    Check the solenoid it could be failing when it warms up
     
  13. oilhead

    oilhead

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    Check the oil line for blockage, especially filters. If the filter is clear, make sure it is bled properly. The burner runs with what is in the pipe, but it is not being replaced quickly enough. When left, it fills up slowly which allows your 2 mins run time.
     
  14. oilboffin

    oilboffin

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    Ok so you've cleaned the filters did you change the actual filter
    you have set the oil pressure at 105 that is 25kw setting so you should have a 0.75 x80degree EH
    Nozzle the air should be about 6 make sure you have a good flow of oil if you have then you may need a new pump.To get 25kw there is another setting 120psi .6x80degreeS
     
  15. spraggo

    spraggo

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    Check that the drive dog (the plastic connecter between the oil pump and motor) is not worn causing it to slip on the spindles??!!
     
  16. oilboffin

    oilboffin

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    A very good point my friend
     
  17. Terrywookfit

    Terrywookfit

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    If it was slipping the oil pressure gauge would fluctuate.
     
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