Right,
The cascade GE can work on gas or electric.
The 3 coloured lights, Green, amber and Red are ONLY for when using gas as the heating source.
If using electric they have no part to play and is controlled by a diferent switch near the heater.
If you are using gas and the red light comes on after a few seconds, it means the gas has failed to light, which means either the gas supply is not ON, or the isolation valve is closed, or there is a problem withthe burner module.