Commissioning
Full Free Cooling
When the ambient is low enough and free cooling can totally satisfy the cooling requirement of the exchange, the
damper will open and the fan will modulate to maintain the design room set point. On low supply temperatures, the
damper will modulate closed.
Mechanical DX Cooling
When free cooling is unavailable, the DX cooling system will maintain the temperature in the room.
Concurrent Mode
When the ambient temperature is below the cabin setpoint yet not low enough to satisfy demand both freeccoling and
mechanical cooling shall be enabled to trim the remainder of the required cooling performance. The control setpoints are
congurable through the controller.
Electric Heating (Optional Extra)
When heating is required, the unit will control as follows:
When the return air temperature drops below the room set point, the microprocessor will select
the stage of electric heating to satisfy the heating requirement of the room. Once the room conditions have been
satised, the electric heating will turn off to leave just the indoor fan recirculating the room air.
Free Heating Mode
In freeheating mode, the freecooling damper is closed and the evaporator fan speed is xed at design speed. No cooling
or heating is enabled, and the unit attempts to use the heat load from within the cabin to reheat the room and prevent
the return temperature from reaching the Critical Low Temperature by simply recirculating cabin air.
Damper Position
In the event of a re alarm signal (from the master BMS system), the damper will be driven shut and the unit will switch
off.
Airow Switch
As standard the airow fail switch is set for the fans to operate at the standard design airow and external static, as
quoted in the Technical manual or if customer specied.
However in instances where the operating conditions are to be varied from the standard then the following procedure to
set up the switch(s) must be followed:
● Set airow to required operating parameter with the use of microprocessor.
● Turn airow switch to maximum setting to test electrical control. Controls should switch off.
● Adjust switch downwards until the control circuit is reactivated.
● Switch off fan (controls should switch off.)
● Turn on fan and re set unit.
Filter Change Switch
To set the lter change switch the following procedure is carried out:
● Adjust the lter change switch until the alarm activates.
● If the alarm is not generated the switch is faulty.
● Turn the lter change switch back to 1.5.
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