Boiler Problem

Discussion in 'Plumbers' Talk' started by Lawrie, Mar 23, 2017.

  1. Lawrie

    Lawrie New Member


    Having trouble with boiler, Ideal Classic NF 230 Open Vented System.

    Boiler fires up all good and runs for 10-20mins then flame cuts out, however fan keeps running and the sparker goes constantly as if trying to relight.

    There's no smell of gas. The overheat reset button doesn't pop, the overheat stat has been replaced anyway but same story.

    The system was recently drained but has been bled and in the time the boiler is on the rads start to heat so seems the water is circulating.

    Tried turning thermostat knob up and down and at very low setting all seems to work normal but turn it up at all and the problem appears.

    Any ideas?
  2. Glad its Friday

    Glad its Friday Active Member

    Would really need to be in front of it to check it out. However, once the desired temperature of the circulating water has been reached the boiler basically shuts down, no sparking, no fan. And when there is a demand, everything starts back up again.

    So if the fan keeps going and the spark ignition is going (can you actually see the spark through the window?) but the gas valve presumably hasn't opened then that would point to a pcb / electrical problem at this stage.

    So if you know what you are doing, I would start by checking the continuity of all the electrical connections especially between the board and gas valve.

    Note that having removed the boiler casing, a flue gas check will need to be done to re-confirm the safe operation of the boiler.
  3. Lawrie

    Lawrie New Member


    Spark is never visible through window but I can hear the spark from the Pilot ignitor and can see the sparker fire on the PCB.
  4. Glad its Friday

    Glad its Friday Active Member

    Then you've a bad connection between the pcb and the pilot.
    Maybe the wire has got trapped on route to the pilot injector and it's earthing out there or a 'cold' solder joint on the pcb when everything warms up.
  5. Lawrie

    Lawrie New Member

    Just for the benefit of anyone that finds this thread, the problem was a faulty solenoid in the gas valve, when hot the electromagnet was failing. New gas valve fitted and all is well.
  6. WillyEckerslike

    WillyEckerslike Well-Known Member

    Good feedback thanks.

    It's really annoying the times that professionals give freely of their advice only to never hear again from the OP or learn if the problem was solved which might also help future visitors solve their problems without having to ask.....
    kiaora, retiredsparks and PhilSo like this.

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