MCAC-2008-11 Air-cooled Modular Chiller
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“11” presents selecting constant compressor (as the auxiliary unit).
9——ADDRESS
0 presents NO. 0 main unit
1～F presents NO 1～15 auxiliary units respectively
For modular units, each module unit has same electrical control function, while the unit can be set as main
unit or auxiliary unit by adjust the address switch of the PCB. The No.0 unit is prescribed as main unit. The
digital module unit must be set as main unit and the others are auxiliary units. As long as being set as main
unit, the module unit’s control system just activates the functions that are the communication with wire
controller, the capacity adjustment, water pump control, auxiliary electric heater control, total water temp.
detect and water flow switch detect.
10——COM (O) 485 communication port (failure code E2).
11——COM (I) 485 communication port (failure code E2).
P, Q, E points of COM (O) and COM (I) are connected with each other for RS-485 communication.
z If failure occurs between the wire controller and main module, all the units stop.
z If failure occurs between main unit and auxiliary unit, the auxiliary unit with communication failure will
stop, and then the number of units online detected by the wire controller will decrease; ”EA” will be
displayed and the indicator lights will flash.
12——System A high-pressure protection & discharge gas Temperature switch protection (protection code
(P0),
System B high-pressure protection & discharge gas Temperature switch protection (protection code (P2),
System A low-pressure protection (protection code P1)
System B low-pressure protection (protection code P3)
z Constant compressor: discharge Temperature switch is connected in series with high-pressure switch.
z Digital compressor: double protection of discharge Temperature Switch and discharge Temperature
Sensor, discharge Temperature Switch is connected in series with high-pressure switch, and the
discharge Temperature Sensor has its own interface.
Digital compressor has discharge Temperature sensor (which is invalid for the constant), protection is
depending on the discharge Temperature (DLT), and it will act for three Temperature areas if the sensor is ok
(failure code E8 means sensor absent): safe area without protection when DLT below 125 ; yellow area ℃
appears in the condition that the capacity dropping down to 40% of the rating, when DLT is higher than
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