baxi solo not firing

[2minutesturkish]

Hi, I have a baxi solo WM 40/0 PF boiler(41-077-51). Couple of days ago noticed no hot water, found no flame through viewing window. Turned up room stat., set timer to all day, turned up cylinder stat to 70degs, still no flame. Turned boiler control to 0, fan switched off (fan always seems to come on whether CH/water on or not), waited couple of mins, reset to max. Fan came on, no ignition. Turned boiler to 0 again. fan off. left like that for several hours, forgot about it until I realised CH should be on, turned control to max, fan came on, clicking sound heard (ignition cct?) boiler ignited. worked fine for a couple of days, then yesterday morning no hot water, repeated previous efforts to no avail. Read thru' forum, stabbed in the dark at electroncs, banged (technician tap, as we call it in my trade; avionics) boiler fired up. Is the prob with "sequence controllers pcb" or was the tech tap a coincidence/red herring and something else is cause. I will get an engineer out this week, but would like a bit of a "heads-up" first. Thanx in advance.

 

[Jethrosbits]

Sounds like a dry joint on the pcb or something similar.

Fiddling around with the board or, as you put it, a "technicians tap" will often sort the problem temporarily but the fault will usually recur until the pcb is either replaced or repaired.

 

[gas4you]

Tech tap could have shifted a relay on the pcb or could have freed the gas valve to open. If you can hear sparking test there is 230V to the gas valve. If so then looks like gas valve sticking. If not could be relay on pcb, or if there is no ticcing probably would be the aps faulty and sticking, again a suitably placed 'tap' could free it

 

[2minutesturkish]

Thanx fellas I'll check out the valve, but hopefully it is a dry joint and I can just re-flow it, if not I'll replace the board. Cheers Scottie