Service Functions - Mitsubishi Electric MSZ-HM09NA-U1 Service Manual

7

SERVICE FUNCTIONS

MSZ-HM09NA MSZ-HM12NA MSZ-HM15NA MSZ-HM18NA MSZ-HM24NA
7-1. TIMER SHORT MODE
For service, the set time can be shortened by bridging of the timer short point on the indoor electronic control P.C. board.
The time will be shortened as follows. (Refer to 9-7.)
• The set time for the ON/OFF timer can be reduced to 1 second for each minute.
• After the breaker is turned on, the time for starting the compressor, which normally takes 3 minutes, can be reduced to
3 seconds. Restarting the compressor, which takes 3 minutes, cannot be reduced.
7-2. REMOTE CONTROLLER P.C. BOARD MODIFICATION FOR INDIVIDUAL OPERATION
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
In this case, to operate each indoor unit individually by each remote controller, the remote controller P.C. boards must be
modified according to the number of the indoor unit.
How to modify the remote controller P.C. board
Remove batteries before modification.
The board has a print as shown below:
J1 J2
The remote controller P.C. board has the print "J1" and "J2". Solder "J1" and "J2" according to the number of indoor unit as
shown in Table 1.
After modification, press the RESET button.
Table 1
1 unit operation
No. 1 unit No modi cation
No. 2 unit
No. 3 unit
No. 4 unit
How to set the remote controller exclusively for particular indoor unit
After you turn the breaker ON, the first remote controller that sends the signal to the indoor unit will be regarded as the remote
controller for the indoor unit.
The indoor unit will only accept the signal from the remote controller that has been assigned to the indoor unit once they are
set.
The setting will be cancelled if the breaker is turned OFF, or the power supply is shut down.
Please conduct the above setting once again after the power has been restored.
OBH746B
2 units operation
Same as at left
— Solder J1
— —
— —
NOTE: For modification, take out the
3 units operation
Same as at left
Same as at left
Solder J2
—
10
batteries and press the STOP/
OPERATE (OFF/ON) button 2
or 3 times at first.
After finish modification, put
back the batteries then press
the RESET button.
4 units operation
Same as at left
Same as at left
Same as at left
Solder both J1 and J2