Turn gas control knob on panel to 'ON' and press it in and hold it there until the gas flows through to the nozzle and igniter.
This may take a few minutes if there is any air in the gas line following a cylinder change. You should hear a feint 'pop' when the gas burner lights-keep holding the gas knob in for a further 30 secs to allow the thermocouple to hold the gas valve open-then releasethe gas knob.
Geoff in Wales
July 2009