Mitsubishi Electric Mr.Slim MSY-D30NA, Service Manual, Page: 18 / 214

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EMERGENCY OPERATION switch
E.O.
SW
E.O.
SW
8-9. EMERGENCY/TEST OPERATION
In case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the front of the indoor
unit. Emergency operation is available when the remote controller is missing, has failed or the batteries of the remote
controller run down. The unit will start and OPERATION INDICATOR lamp will light.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The Indoor fan speed runs at
High speed and the temperature control does not work.
After 30 minutes of test run operation the system shifts to EMERGENCY COOL/HEAT MODE with a set temperature of
75°F (24°C). The fan speed shifts to Med.
The coil frost prevention works even in the test run or the emergency operation.
In the test run or emergency operation, the horizontal vane operates in VANE AUTO ( ) mode.
Emergency operation continues until EMERGENCY OPERATION switch is pressed once or twice or the unit receives any
signal from the remote controller. In case of latter normal operation will start.
NOTE : Do not press EMERGENCY OPERATION switch during normal operation.
8-11. CHANGING TEMPERATURE INDICATION (°F /°C)
8-10. 3-MINUTE TIME DELAY OPERATION
When the system turns OFF, compressor will not restart for 3 minutes as 3-minute time delay function operates to protect
compressor from overload.
The preset unit is °F.
°F → °C : Press RESET button while the
temperature buttons are pressed.
°C → °F : Press RESET button or remove
the batteries.
•
•
•
Press RESET button gently using
a thin instrument.
Operation mode COOL
HEAT
(MUZ)
Set temperature 75°F (24°C) 75°F (24°C)
Fan speed Med. Med.
Horizontal vane Auto Auto
The operation mode is indicated by the Operation
Indicator lamp as following
Operation Indicator lamp
(MSZ type)
EMERGENCY COOL
↓
EMERGENCY HEAT
↓
STOP
(MSY type)
EMERGENCY COOL
↓
STOP
Lighted
Not lighted