Gas rings won't light

[Rob Graham]

We've a 10 year + old Smeg hob. The rings are an Aluminium casting with a glazed steel casting as the spreader. Her-indoors got replacement spreaders recently and the consistently of the flame igniting has dropped really seriously. The sparks are fine but ignition is now lousy.

Any suggestions ?

One curious feature I found was the smallest ring which would light ok when cold but not when hot; I took the spreader off and chucked it into to some water to cool it down and it then lit quite happily !!

Rob

[Andrew Gabriel]

I've used a number of gas hobs which were significantly more difficult to light when hot. I suspect the heat generates local convection currents which mean the gas/air mixture at the spark is outside the combustion range, which isn't actually very large.