Service Functions; Change In Defrost Setting Muh-A07/A09/A12Wv; Timer Short Mode; P.c. Board Modification For Individual Operation - Mitsubishi Electric MSC-A07WV Service Manual

12

SERVICE FUNCTIONS

MSC-A07WV -
E1
MSC-A09WV -
E1
MSC-A12WV -
E1
12-1. COMPULSORY DEFROSTING MODE FOR SERVICE
By short circuit of the connector JPDS and JPSG on the outdoor deicer P.C. board, defrosting mode can be accom-
plished regardless of the defrost interval restriction. (See page 125.)
Defrost thermistor RT61 must read below -3°C.
12-2. CHANGE IN DEFROST SETTING
<JRF> When the JRF wire of the deicer P.C. board is cut, the defrost interval time will be changed. (See page 125.)
<JRG> When the JRG wire of the deicer P.C. board is cut, the defrost temperature will be changed. (See page 125.)
MODEL
MUH-A07WV -
E1
MUH-A09WV -
E1
MUH-A12WV -
E1
Note: MXZ-A18WV is not equipped with the system to change the setting of defrosting. The unit has been set to perform
more effective defrosting than conventional models, so it is not necessary to change the setting even in the area where
frost forms easily. Refer to page 100, 11-15. Heat defrosting control, for defrosting control.

12-3. TIMER SHORT MODE

For service, set time can be shortened by short circuit of JPG and JPS the electronic control P.C. board.
The time will be shortened as follows. (Refer to page 124.)
Set time : 1 minute
Set time : 3 minutes

12-4. 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, P.C. boards of remote controller 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 :
Table 1
No. 1 unit
No. 2 unit
No. 3 unit
No. 4 unit
MU-A07WV - MUH-A07WV -
E1
MU-A09WV - MUH-A09WV -
E1
MU-A12WV - MUH-A12WV -
E1
<
MUH-A07/A09/A12WV
Jumper wire
Defrost interval time changes from 40 minutes to 15 minutes
JRF
Deforst start temperature changes from -3: to 0:
JRG
Deforst finish temperature changes from 3.1: to 10.1:.
1-second
3-second (It takes 3 minutes for the compressor to start operation. However, the starting time is
shortened by short circuit of JPG and JPS.)
1 unit operation
No modification
–
–
–
MUX-A10WV -
E1
MUX-A19WV -
E1
MUX-A20WV -
E1
<
MUH-A07/A09/A12WV
>
2 units operation
Same as at left
Solder J1
–
–
102
MUX-A25WV -
E1
MUX-A26WV -
E1
MXZ-A18WV -
E1
>
Change point
NOTE : For remodelling, take out the bat-
teries and push the
OPERATE/STOP(ON/OFF) button
twice or 3 times at first.
After finish remodelling, put back
the batteries then press the
RESET button.
The P.C. board has the print "J1" and "J2".
Solder "J1" and "J2" according to the num-
ber of indoor unit as shown in Table 1.
After modification, press the RESET button.
3 units operation
Same as at left
Same as at left
Solder J2
Solder both J1 and J2
–
E1
E1
E1
4 units operation
Same as at left
Same as at left
Same as at left