This valve makes it possible to balance pressure differences between internal and external pressures of a cold room.
This is done through venting through the cold room wall.
The valve is a heated mechanically operated valve, with two water tight mobile flaps, one for the intake one for the exhaust. It is adjusted to operate over a given pressure of about 10mm water column.
The heating has a thermal contact to control the heating element temperature. The heater is rated at 40 watt / 230 volts.
Correct electrical fused connection by qualified personnel is suggested.