Mitsubishi Electric MSZ-HM09NA-U1 Service Manual page 15

8-6. EMERGENCY/TEST OPERATION
In the case of test run operation or emergency operation, use EMERGENCY OPERATION switch on the right side of the
indoor unit. Emergency operation is available when the remote controller is missing or has failed, or when the batteries in
the remote controller are running down. The unit will start and OPERATION INDICATOR lamp will light up.
The first 30 minutes of operation is the test run operation. This operation is for servicing. The indoor fan 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 the latter case, normal operation will start.
NOTE: Do not press EMERGENCY OPERATION switch during normal operation.
8-7. 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.
8-8. Changing temperature indication (°F/°C)
• The preset unit is °F.
• °F °C: Press RESET button while the TEMPERATURE buttons are pressed.
• °C °F: Press RESET button while the TEMPERATURE buttons are pressed.
OBH746B
EMERGENCY OPERATION switch
Operation mode
Set temperature
Fan speed
Horizontal vane
The operation mode is indicated by the
Operation Indicator lamp as follows:
Operation Indicator lamp
EMERGENCY COOL
EMERGENCY HEAT
STOP
15
COOL HEAT
75°F (24°C) 75°F (24°C)
Med. Med.
Auto Auto
Lighted
Not lighted
Press RESET button gently
using a thin instrument.