oil boiler cutting out

Discussion in 'Plumbers' Talk' started by jonc, Jun 14, 2006.

  1. jonc

    jonc New Member

    Any suggestions!!

    I've just refilled my central heating system after moving a radiator. The radiators have all bled OK but when I turn the boiler on it only lasts 3 minutes before cutting out. When cooled it will start up again. Pump seems to be running fine.

    I'm assuming that air is in the boiler. It's a Boulter Economy oil boiler. Any ideas on how to bleed the boiler as I can't see any obvious bleeding points.

  2. heatyman

    heatyman Member

    When you say it is cutting out, is the burner going to lockout,is it just stopping on its control thermostat or is it tripping the limit thermostst?
    Does the flow pipe go down out of the boiler or does it rise. you may find your airlock is somewhere else other than in the boiler.
  3. jonc

    jonc New Member


    I'm not sure about the difference between the three but I think it's stopping on its control thermostat. If i turn the thermostat up in the burner it will start until it reaches that higher temperature. Given 20 minutes to cool and it starts up again.
    The flow pipes rise from the boiler. One of them gets piping hot the other just warm.
    I keep bleeding the circulation pump and sometimes that make a gurgling sound in the system.
    I've run out of ideas how to get the air out.

    Any suggestions appreciated!
  4. heatyman

    heatyman Member

    You need to follow the flow pipe(the hot one) until you find where it goes cold, there is your airlock. Without seeing the full system configuration it is difficult to be more helpful
  5. The Enforcer

    The Enforcer New Member

    On my oil boiler I have a clear plastic tube inside the boiler which shows a big air bubble in the oil line. There is a hex-key fitting somewhere along that line which when turned (1/4 - 1/2) will pull the air out. It is normal to have to have a bubble or a few bubbles in that pipe though.

    Hope this helps.
  6. heatyman

    heatyman Member

    DWD, the problem is with the water circulation, not the oil supply. If you have a wall mounted boiler, (HRM Wallstar perhaps?) then it is common to have a bubble in the oil line. They still seem to work with it.
  7. jonc

    jonc New Member

    Thanks for the suggestions Heatyman, I'm going to have another crack at it tomorrow.

    I noticed that in a previous topic, somebody said an engineer got rid of air from an oil burner system by disconnecting the thermostat and keeping it running until the air was forced out.

    Does this sound worth a try or am I likely to blow up a sleepy little village in Sussex?!!
  8. heatyman

    heatyman Member

    I wouldn't recommend that. If you have a limit stat, then that would cut out your burner anyway, if you override that, you're likely to put more air into it when the boiler boils.
    It may be a 'faff', but at least you'll begin to understand your system which will help in the future.
  9. jonc

    jonc New Member

    Thanks Martin,

    I followed your advice about tracing back the hot pipe until it was cold and there, hidden behind the emersion, i found a bleed valve - hey presto.

  10. Ori

    Ori New Member


    I have a similar issue with an oil boiler cutting out. The system was drained and new radiators fitted, with new pipe routing in some cases. The boiler fired up fine but only run for a few minutes before cutting out and initially only heated the pipes upto to the upstairs cupboard where the flow and return pipes start to go off to the radiators. I have bled the radiators and after waiting 10 - 15 mins fired the boiler again only for it to cut off. The pipes are heating up further along the flow on each occasion I go through this process but the radiators no longer release any air. The boiler runs for approximately 4minutes each time. Any advice would be greatly appreciated.

  11. heatyman

    heatyman Member

    All I can suggest is to follow the pie pasdt the warm section to see if there is any obvious air traps.do you have any air vents in the pipework that you may have overlooked? Is your system fullypumped or gravity DHW? If fully pumped there could be an airlockin the coil of the cylinder that is stopping circulation. Have you bled the pump? Is the motorised valve(s) open?
  12. Ori

    Ori New Member

    The pump was the cause and after some manual intervention the flow is now going around the radiators.

    Thanks for the advice

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