6. FROST PROTECTION MODE
CAD HE 325/450/575 EC V BASIC:
All standard units have an automatic frost protection system installed. In the case that the
exhaust air (EHA) temperature fall below 5°C and the outdoor air temperature is less than
0°C the defrost mode will start. The supply fan decreases the velocity whilst the exhaust fan
works on the nominal airflow. This unbalance avoids the building of ice into the exchanger.
In case that this unbalance will not be enough the unit stops during 2 hours. Every 2 hours
the CAD will start-up for a short time to check if the temperature conditions are favourable
to return to work normal.
We recommend not to use this unit in combination with devices which are using com-
bustion air unless there is a security device installed which would switch of the unit
in case of pressure difference in the house.
CAD HE 325/450/575 EC V BASIC PH:
In the "PH" units there is installed an electric heater element as a pre-heater. This pre-heater
avoids the ice building in the exchanger without unbalancing the airflows and works fully
autonomous without any need for adjustments from user side.
Function:
In the case that the exhaust air (EHA) fall below 5°C the frost protection starts activating
the pre-heater. The pre-heater is working proportional in dependency of the temperatures
measured by the unit. If the power of the pre-heater is not enough to keep the exhaust tem-
perature (EHA) above 3°C the velocity of both fans will be reduced proportionally in order to
increase the temperature for the supply air. If this is still not enough, to the avoid freezing of
the exchanger, the unit stops during 2 hours. Every 2 hours the CAD will start-up for a short
time to check if the temperature conditions are favourable to return to work normal.
Technical datas:
Electrical supply: ~230 Vac 50 Hz
Power: 1500 W
Absorbed current: 6,8 A
Thermal difference at nominal airfl ow:
: Electric power
: Electric power
Q: Airflow
: Specific heat of air
: air density
35
