we have just returned from a night away in our van, took the van to the storage place (about 45 mins away), got home and I remembered I had not switched off the water heater switch. we didn't know if this would run off battery and try and heat up water that wasn't there (I had drained all water from system) so we got back in car and drive back to storage place and had to take caravan out just to go and flick a switch! Hubby was not pleased! Did we actually have to do this? (just out of interest) we thought it better to be safe than sorry but was it really necessary?