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Boiler iginition cutoff

The flame sensor should be on the opposite side of the burners to were the ignition proble is, And check whether the flame is getting across to the flame sensor, The idea is that the flame has to light across ALL the burners.I had an instant were the flame did not get across to the far side. This was caused by rust in the wings of the burners which prevented the flame from travelling across.
If it's an intermittent fault you may have to watch several times to see whether the this happens, More likely to happen when the burners are hot from previous operation, NOTE, Don't put your face down too close to the burner opening (or any gas Burner)incase there is a blow back which can singe eyebrows, hair, moustaces or your face.I know from experience this can happen.


  • boiler cutoff

    I'm having a problem with a relatively new Dunkirk gas fired steam boiler. I just moved into a house with this system and I've noticed that the boiler doesn't always fire on the 1st, or sometimes 2nd and 3rd attempts. After removing the front panel and watching it fire I'm seeing, on the failed attempts, that the gas is flowing, is being ignited, the burners are lit but after 2 seconds or so something is cutting them off. After 5 minutes, the regular refresh cycle, it'll attempt again. Eventually it'll fire. This is an intermittent problem and seems worse when the boiler has been cold for several hours. I suspect a problem with one of the fault sensors, either the flame roll-out or the damper obstruction. Given the fact that the system eventually overcomes the problem I tend to think it's more electronic than mechanical. I should note also that the damper control is mounted close to the top of the boiler. Could this have anything to do with it?


  • Michael H
    Michael H Member Posts: 4

    I would check the flame sensor, or just clean it with a small wire brush.

  • where would i find it on a 4 year old Dunkirk boiler?

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