my gas hob has several of the bigger rings including the big central ring which wont stay lit, i hole down the knob to get the gas to flow and the electric spark triggers flame burns, and then if you take the hand off the knob the gas goes off.
ive tried standing and holding knob down for ages as i understand its a thermo couple which switches the gas on at the ring, for ages and some times it works but most of the times it is useless, any ideas?