Hi. I have a truma waterheater that will not work on gas but works perfect on electric. Both worked fine until the element went on the electric which was replaced since then the water heater will not work on gas i replaced the element myself which was easy enough. The light on the gas knob doesnt even light up when swicthed on . The cowl cover is removed and all other gas appliances work fine. Thanks for any help hope its something stupid. If not looks like booking it in.