Units with preheating register and enthalpy heat exchanger

Units with preheating register and enthalpy heat exchanger have a special frost protection strategy. The combi sensor fitted in the exhaust air duct of the ventilation unit determines the exhaust air humidity. The freezing temperature is calculated on the basis of the exhaust air humidity and the current volumetric flow.

The preheating register controls the unit inlet temperature using this calculated value + an offset so that the enthalpy heat exchanger cannot freeze. The enthalpy heat exchanger reaches a freezing temperature when the unit inlet temperature is between -5 °C to -12 °C, depending on humidity and volumetric flow.