TRUMA FROST CONTROL VALVE Truma Frost Control valve - frost control valve kit for 10mm flexible pipe work . This valve is temperature sensitive and will drain the boiler if the temperature in the boiler compartment drops below approx. 4 degrees C. The valve must be mounted in the same compartment as the boiler so that it will not operate while the boiler is working, as it will sense the radiated heat from the boiler. FROST CONTROL The ideal frost protection. The current-free safety/drain valve empties the boiler automatically if there is a risk of frost. This means the discharge equipment cannot freeze up and your water supply is perfectly safe. FUNCTION The water is drained intermittently via a discharge nozzle in the event of over pressure If there is a risk of frost, the Frost Control opens automatically and releases the water in the boiler to the outside via a draining connection. The valve can also be opened manually.