Mitsubishi Heavy Industries FDT28KXE6A Service Manual page 30

(3) Outdoor fan snow protection control (Master unit/Slave unit)
(Note) Following explanation is based on setting function with 7-segment display [C75].
However the following terminals and 7-segment function settings are available to use.
CnS1: [P11]-[5]
(a) The setting of this control should be done not only on the master unit but also on the slave unit, because the fans of master
unit and the slave unit are controlled independently.
(b) The control is enabled /disabled by selecting [0] or [1] displayed at 7-segement LED of master/slave units.
(c) Operation method of outdoor fan snow protection control
(i) Set the code [C75] on 7-segment display
(ii) "0" or "1" is displayed at the data display area of 7-segment LED.
"0": Outdoor fan snow protection control is disabled (Factory setting)
"1": Outdoor fan snow protection control is enabled
(iii) Press SW7 (Data write/delete) for 3 seconds continuously
(iv) "0" or "1" blinks every 0.5 second at the data display area of 7-segment LED.
(v) Press SW8 (one digit) to toggle the display between "0" and "1".
(vi) If SW7 is pressed for 3 seconds continulouly while "0" and "1" are blinking, "0" or "1" at the data display area of
7-segment LED stops blinking.
With this operation, the enabled/disabled setting of outdoor fan snow protection control is saved in the memory of
EEPROM, and henceforth the outdoor fan is controlled according to the contents of memory.
(vii) Contents of outdoor fan snow protection control are retained even if the power is turned off and backed on again.
(d) Contents of outdoor fan snow protection control
(i) At the status of all stop or emergency stop, if the outdoor air temperature drops 3°C or lower, all of outdoor fans are
operated at the maximum speed (4th speed) once every 10 minutes.
(ii) The outdoor fan runs for 30 minutes
(iii) During this snow protection control, the magnetic
contactor 52C1 of the compressor is ON
(4) Forced cooling /heating operation (Master unit)
(Note) Following explanation is based on using CnG1 terminal and setting function [P13]-[2] with 7-segment display.
However other terminals can be used with following function setting of 7-segment display.
CnS1: [P11]-[2]
(a) When SW3-7 on the outdoor control PCB is turned ON after setting function [P13]-[2] with 7-segment display, if CnG1 is
shorted, forced heating operation is performed, but if CnG1 is open, forced cooling operation is performed.
(b) If the different mode from the forced operation mode is commanded from indoor unit, the "mode unmatch" message is
displayed on the LCD of remote controller and the operation is entered in FAN mode.
SW3-7
(5) Emergency stop control
When one of indoor units receives the emergency stop signal through CnT terminal on the indoor control PCB from the device
like as refrigerant leakage detector and that information is tarnsmitted to the outdoor unit, the outdoor unit stops opeartion and
emergency stop error message transmitted to all indoor units running.
It is able to make the emergency stop function effective by remote controller indoor function setting.
(a) When the outdoor unit receives the "Emergency stop" command from the indoor unit, it makes all stop by error.
(b) And the "Emergency stop" command is transmitted to all indoor units and error code "E63" is displayed.
(c) When the outdoor unit receives the "Emergency stop reset" command from the indoor unit, the "Emergency stop reset"
command is transmitted to all indoor units.
CnS2: [P12]-[5]
CnS2: [P12]-[2]
Open
ON CnG1
Shorted
OFF Normal operation
CnG1: [P13]-[5] CnG2: [P14]-[5]
CnG2: [P14]-[2]
Operation in cooling only
Operation in heating only
28
- -
Fan ON
Fan OFF
3 5
Outdoor air temperature (°C)