Anyone help with this. Truma not turning on & showing H517 and the warning triangle. Had this before & after I filled up with autogas propane it worked. Today I have gas ( ie gas at the double hob). Not sure if gas is low & so that’s why Truma not firing ( low pressure?). But - the question is: Why can’t I use the electric to heat. Nothing works on the Truma. Would have thought that running out of gas should not stop the system using electric only. Any advice? Thanks