Your boiler's small pilot flame is lit, but the main burner is failing to ignite to provide heat or hot water.

Technical description

Check supply voltage; If no supply check the fuse in the plug or other supply point; Is there a supply voltage at the input to the control box; Set any CH and HW controls to CONTINUOUS position; Check the settings of the room and cylinder thermostats; If no supply - check the controls; Check the boiler thermostats; Replace the gas control valve.