After a cold night, a puddle of water may appear under a camper even if there is no leak. Many campers with a Trumaⓘ Combi heater have a FrostControl valve that opens automatically at around 3 degrees Celsius and drains water from the boiler to prevent frost damage. In Combi 4 and Combi 6 systems, the water volume is 10 litres. The valve can only be closed manually after the temperature around it rises to about 7 degrees Celsius. The protection does not replace full winterisation: water must still be drained from pipes, taps and the pump.
