Useless Boiler Stops then comes back on randomly then stops again?

My Boiler keeps doing this , it stops working randomly then i leave it for half a month or a month and it starts working again out of no ware with out anyone touching it , then it stays on for maybe 2 months and it stops working again... it's winter and now it's turned off again, so i have no damn heating because it decided to stop working again.. i got a guy to come and check it awhile back but he found nothing wrong with it and didnt know what was wrong with it ..and he was suppose to be qualified person to deal with stuff like this .. it ended up working again randomly while he was there he saw it go on with out him touching or doing anything to it .. he said that he didnt touch anything when he saw that it started working again...

i dont know what the hell is wrong with it it's like it has a mind of it's own

anyone have any ideas on what could be the problem?

is it happening to anyone else?



the boiler is only 3 years old , almost 4 now.

3 Answers

  • 8 years ago
    Best Answer

    There are lots of possibilities.

    You don't say if it's a combi or conventional boiler, so some guesswork...

    Either way, firstly check the boiler 'run' terminal using a multimeter or neon screwdriver.

    That's the signal from the external controls (timer & room stat etc.) for the burner to ignite.

    It should be Live (240V) if the external control is asking for heat.

    If that is not appearing, it's the wiring outside the boiler.

    For a non-combi, one of the first things to check is the motorised valve which directs flow to either radiators or hot water tank - they often go 'sticky' and the switches inside them don't operate properly. Usually a new motor unit will fix that, about a tenner from a plumbing supplies.

    Also check the main heating junction box where the timeswitch & thermostat cables interconnect. Turn the mains off to the heating first and carefully check all the terminals for loose or improperly fitted wires, like with the screw on the insulation instead of the copper.

    Some systems don't have a motorised valve & one wiring style for that takes the boiler run signal from the common contact on the hot water cylinder thermostat, so make sure you check every possible component & terminal, not just things that appear to be for central heating!

    If the boiler is getting the run signal but not working:

    The first thing that should happen is the fan start to circulate air for the burner.

    They quite often don't run right or seize up due to failed bearings. If the fan is not free, the boiler will not fire.

    There is a pressure switch that senses the air pressure across the boiler burner to monitor the fan.

    If that does not 'see' pressure, the boiler will not light.

    There is also a water thermostat to control the internal temperature of the boiler. Again, a fault with that will shut it down.

    And, everything in the boiler is linked via a microprocessor based control board, which can fail or go erratic.

    If it's nothing obvious, try a different engineer - any decent one should be able to fault-find it properly & not be stumped by it..

    If you want further info on here, post again giving the exact type of the boiler.

  • 3 years ago

    From the constrained techniques provided my best guess may well be you have in no way relatively considered or experienced what's mandatory to “have confidence” to commence with, and in case you think of a real perception creates an much less annoying existence, you're very lots wrong. (Luke 9:23) “Then he went directly to assert to all: “If all people needs to return after me, enable him disown himself and %. up his torture stake on an well-known basis and persist with me continuously.”

  • Tony
    Lv 6
    8 years ago

    sounds like the control board of the bolier is faulty .... and if it is, this is quite expensive to replace!! depending on the age of the boiler, it may be RIP boiler!!

    get a reputable plumber in ASAP

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