My problem has evolved, so I thought it best to start a new thread....
In a nutshell, when I turn on the CH, the sequence is as follows: pump comes on, fan comes on, something clicks, then flame comes on with orange light. After about 10 seconds or so, something clicks and flame goes out, fan goes off, pump stays on.
Fan starts again, but goes off within 1 second, and again, and again (the number of tries varies), then eventually fan starts and flame comes on with orange light. Cycle repeats. It does this in perpetuity and my radiators get quite hot eventually.
DHW, same cycle as above but eventually it does stay on, this morning it took 5 minutes of this cycle and stayed on, yesterday nearly 15 minutes before it stabilised.
The CH never stabilises and it's on/off/on/off all the time.
i've had the same gas engineer out twice this year, both times the problem was fixed, but the last time he was really scratching his head, and was seemingly replacing bits willy nilly until the problem righted itself. He replaced the PCB as a primary solution, which as I understand is one of the last things that needs doing, then resorted to putting the old one back in and replacing the air pressure switch, pumping up my expansion vessel and changing the DHW heat exchange unit.
This time I hope it's something simple like a thermistor that needs changing, this things costing more than I would like!!
All help or suggestions gratefully received as always!
cheers
Jon
In a nutshell, when I turn on the CH, the sequence is as follows: pump comes on, fan comes on, something clicks, then flame comes on with orange light. After about 10 seconds or so, something clicks and flame goes out, fan goes off, pump stays on.
Fan starts again, but goes off within 1 second, and again, and again (the number of tries varies), then eventually fan starts and flame comes on with orange light. Cycle repeats. It does this in perpetuity and my radiators get quite hot eventually.
DHW, same cycle as above but eventually it does stay on, this morning it took 5 minutes of this cycle and stayed on, yesterday nearly 15 minutes before it stabilised.
The CH never stabilises and it's on/off/on/off all the time.
i've had the same gas engineer out twice this year, both times the problem was fixed, but the last time he was really scratching his head, and was seemingly replacing bits willy nilly until the problem righted itself. He replaced the PCB as a primary solution, which as I understand is one of the last things that needs doing, then resorted to putting the old one back in and replacing the air pressure switch, pumping up my expansion vessel and changing the DHW heat exchange unit.
This time I hope it's something simple like a thermistor that needs changing, this things costing more than I would like!!
All help or suggestions gratefully received as always!
cheers
Jon