We’ve a Truma CP 25-UK. Works fine on gas, and on EHU. There’s a setting for gas only. However we are on EHU and it doesn’t like being asked to work on gas only for heating - get an error code. Is this normal? We’re paying E on a meter and reckon G would be cheaper for warm air. Want E only for tv, phone charge, lights. Do we need to unplug? There is a winter setting for both G and E (functions without error) but that’s going to use E - wot we wish to avoid. Any experiences/advice would be appreciated