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INTRODUCTION OF DIAL SWITCH
Dial switch
1. SW4-1: OFF-Traditional EA fan defrost ON-OA side electrical heater defrost
2. SW4-2: OFF-Auto by-pass and manual bypass via voltage free connector (free cooling)
3. SW4-3: OFF-CO2 sensor only ON-Humidity sensor and CO2 sensor
4. SW4-4: Reserve
Attention: Please cut off the power before dialing.
1� SW4-1 is switching the defrost mode� Default is “off”, it means traditional defrost by EA fan� When
turn to “on”, the defrost mode is changed to be OA side heater defrost (required to connect the heater
to the OA duct, only suggested in winter under –15°C), at this time the parameter 01 would be turned
to 0 automatically and the supply air side electrical heater is not able to use�
Under electrical heater defrost mode, controller can automatic drive the electric heater on/off to heat
the fresh air in order to prevent frosting at the EA side of heat exchanger�
1) If the outdoor fresh air temperature < -15°C, the OA heater turns on for 50 minutes, then the ventilator
switches off for 10 minutes and restarts�
2) If the OA heater switches on and the exhaust air temperature still <-1°C, then the ventilator will
stops for 50 minutes�
3) If the exhaust air temperature <-1°C and the outdoor air temperature >-15°C, the OA heater switches
on for 10 minutes for defrosting�
4) If the OA heater is on and temperature of outdoor air is >+25°C, then OA heater will stop for 5
minutes, If the outdoor air temperature is detected over 25°C by sensor over 3 times, electrical heater
stops�
2� SW4-2 is the by-pass mode� Default is “off”, it means that by-pass will open automatically based on
the outdoor temperature. After connecting the bypass free voltage connector (refer to the wiring diagram),
then bypass damper opens manually and fans run at high speed�
3� SW4-3 is switching the forced ventilation mode� Default is “off”, it means that ventilator is controlled
by CO2 sensor� When turn to “on”, the ventilator is controlled by humidity and CO2 sensor, if SW4-3
turn to “ON” but without connecting humidity sensor, then E3 error happen�
4� SW4-4 is reserved�
External ON/OFF switch control logic
External switch can receive voltage free signal to control the ventilator on or off�
-Ventilator off, when ventilator have external on signal, ventilator run at high speed, when ventilator
have external off signal, ventilator return back to off�
- Ventilator on, when ventilator have external on signal, ventilator run at high speed, when ventilator
have external off signal, ventilator return back to previous fan speed�
