my Sroves range cooker is not lighting most times, but does so on the odd occasion. The piezo seems to be working adequately with a good spark ! The fan also comes on, but the gas fails to light. It is if there is no gas coming out. Any ideas :-))
1 gas valves are sealed with grease sometimes this can block the pilot position, it could explain how sometimes it does work.
2 is it lighting but not staying when you release the knob, that would point to the thermocouple not recieving enough heat or being u/s
3 it could be a blocked main jet this can happen if you open roast a lot
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