Service Functions - Mitsubishi Electric OBH839 Service Manual

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8

SERVICE FUNCTIONS

MSZ-AP15VG MSZ-AP20VG
8-1. TIMER SHORT MODE
For service, the following set time can be shortened by bridging the timer short mode point on the electronic control P.C.
board. (Refer to 10-7.)
• 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.
8-2. HOW TO SET REMOTE CONTROLLER EXCLUSIVELY FOR A PARTICULAR INDOOR UNIT
A maximum of 4 indoor units with wireless remote controllers can be used in a room.
To operate the indoor units individually with each remote controller, assign a number to each remote controller according
to the number of the indoor unit.
This setting can be set only when all the following conditions are met:
• The remote controller is powered OFF.
• Weekly timer is not set.
• Weekly timer is not being edited.
(1) Hold down
button on the remote controller for 2 seconds to enter the pairing mode.
(2) Press
button again and assign a number to each remote controller.
Each press of
(3) Press
button to complete the pairing setting.
8-3. AUTO RESTART FUNCTION
When the indoor unit is controlled with the remote controller, the operation mode, the set temperature, and the fan speed
are memorized by the indoor electronic control P.C. board. "AUTO RESTART FUNCTION" automatically starts operation in
the same mode just before the shutoff of the main power.
Operation
If the main power has been cut, the operation settings remain.
After the power is restored, the unit restarts automatically according to the memory.
(However, it takes at least 3 minutes for the compressor to start running.)
How to disable "AUTO RESTART FUNCTION"
Turn off the main power for the unit.
Cut the jumper wire to JR77 on the indoor electronic control P.C. board. (Refer to 10-7.)
NOTE:
The operation settings are memorized when 10 seconds has passed after the indoor unit was operated with the remote
controller.
If main power is turned OFF or a power failure occurs while AUTO START/STOP timer is active, the timer setting is can-
celled.
If the unit has been off with the remote controller before power failure, the auto restart function does not work as the
power button of the remote controller is OFF.
To prevent breaker OFF due to the rush of starting current, systematize other home appliance not to turn ON at the same
time.
When some air conditioners are connected to the same supply system, if they are operated before power failure, the start-
ing current of all the compressors may flow simultaneously at restart.
Therefore, the special counter-measures are required to prevent the main voltage-drop or the rush of the starting current
by adding to the system that allows the units to start one by one.
OBH838A
button advances the number in the following order: 1 → 2 → 3 → 4.
Indoor electronic
control P.C. board
JR77
CN111
CN151
10
R111
IC112

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