Mitsubishi Electric MSZ-FH12NA Service Manual page 19

8-13. 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 opera-
tion is for servicing. The indoor fan runs at High speed and the tem-
perature 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 Medium.
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.
8-14. 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.
8-15. 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 or remove the batteries .
OBH683D
Operation mode
Set temperature
Fan speed
Horizontal vane
The operation mode is indicated by the Operation
Indicator lamp as following
Operation Indicator lamp
EMERGENCY COOL
EMERGENCY HEAT
STOP
19
COOL/HEAT
75°F (24°C)
Med.
Auto
↓
Lighted
Not lighted
↓
Emergency
operation switch
(E.O. SW)
Press RESET button gently
using a thin instrument.