Mitsubishi Heavy Industries SRK25GZ-L1 Handbook page 836

FDC-HKX
(14) Silent mode control
Silent mode is selected if the CnG (equipped with short circuiting pin) is shorted during normal operation.
(a) When the highest speed for the specific model of outdoor fan (140 : 3 speed, 224, 280 : 4 speed) is selected, the speed is stepped
down by one step.
However, the following cases are excluded:
1 For 30 seconds after starting operation
2 For 30 minutes after the compressor stop due to actuation of 63H1 or CT2 during cooling
3 For 2 minutes after changing the number of operating compressors from 1 to 2 units
(b) Upper limits of compressor operation frequency are specified as follows. (Excluding during defrosting)
140: 65 Hz (CM1 - 90 Hz)
(15) Backup operation (Only for 224, 280 models)
If the dip switch SW3-2 is turned ON, operation continues with CM1 (inverter compressor) only for emergency when CM2
(without inverter) is stopped by trouble.
(a) Upper limit of operating frequency is set at 90 Hz for 224 or 95 Hz for 280 and distributed to indoor units proportionally
divided.
(b) Overcurrent error, open T phase error, discharge temperature error (Tho-D2) and discharge pipe sensor error (Tho-D2) on
CM2 are not detected.
(16) Indoor/outdoor connection unmatch check function
If dip switches SW3-4, 5 and 6 are turned ON, a test run operation is performed from outdoor so as to inspect the unmatch in the
connection between indoor and outdoor.
(a) When crankcase heater power ON control is effective
1) Both in- and outdoor units are stopped after a cooling test run operation till the operation time of compressor (CM1) is
accumulated at 16 minutes.
(Indoor expansion valve fully open, indoor fan OFF, "Center" display on remote control)
2) Heat exchanger temperatures on all indoor units are checked 3 minutes later or after release of 6-minute start delay of CM2.
Then outdoor units only are started to check, at intervals of 20 seconds, if the indoor heat exchanger temperatures have
dropped 7 degrees or more compared with those before the re-start.
3) If there is any unit on which the temperature does not drop 7 degrees or more after continuing the check for 5 minutes, the
error is displayed on the remote controller and the outdoor unit.
If it is normal, "- - -" is flashed on the 7-segment indicator and the unit is stopped.
Flashing on the 7-segment indicator can be returned to the normal display by turning SW3-4 to OFF.
(b) When the crankcase heater power ON control is not operating
(i) During normal operation
1) Both indoor and outdoor units are stopped after cooling test operation for 3 minutes. (Indoor expansion valve fully open,
indoor fan OFF and "Center" display on remote controller)
2) Heat exchanger temperatures on all indoor units are checked 3 minutes later or after release of 6-minute start delay of CM2.
Then outdoor units only are started to check, at intervals of 20 seconds, if the indoor heat exchanger temperatures have
dropped 7 degrees or more compared with those before the re-start.
3) Detail of display is same as (a), 3) above.
(ii) When the compressor has been stopped for more than 6 hours
1) Cooling test run operation is continued till the compressor (CM1) operation time is accumulated at 8 minutes and then both
in- and outdoor units are stopped.
(Indoor expansion valve fully open, indoor fan OFF, "Center" display on remote controller)
2) Heat exchanger temperatures on all indoor units are checked 3 minutes later or after release of 6-minute start delay of CM2.
Then outdoor units only are started to check, at intervals of 20 seconds, if the indoor heat exchanger temperatures have
dropped 7 degrees or more compared with those before the re-start.
3) Detail of display is same as (a), 3) above.
834
224: 100 Hz (CM1 -80 Hz, CM2 - ON)
280: 115 Hz (CM1 - 80 Hz, CM2 - ON)