I have a Potterton Promax Combi HE Plus. It is showing error code E133 which means "gas supply has been interrupted, ignition has failed or the flame has not been detected". It can also be caused by a frozen condensate pipe.
When I reset the boiler it makes all the correct noises and the temperature starts to climb, but within 60 seconds it shows E133 again. I've poured hot water outside the external condensate pipe in case but no change.
There is no little window to observe if the pilot light is lit or not. Pressure reads as fine.