Home heating ?

it could be the thermocouple,thats the bit the pilot light heats up,as it heats up the fluid goes down the tube and operates the gas valve ,worth a try

gts
January 2015

I am not an engineer of any sort so my views are of no value.

I would guess that the pilot is being ignited but the flame is too weak to trigger the sensor so that the main burner can be opened - eventually and with luck the heat builds up and the main gas valve operates.

It may be that the flame is too weak or that the sensor is slightly defective.

Sometimes soot builds up on the pilot jet.

But I know nothing.

Good luck...
January 2015