Hitachi RAC-70YH7, Service Manual

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1. Switch OFF main power supply.
2. Short circuit between JW001 and JW002.
3. Switch ON main power supply – LD302 will blink 1 time.
4. (Within 3 minutes) Press Test/Service Switch for 1 second or more.
5. Self-diagnosis result will be shown – LD303 will ON (LIT) and LD301 will be blinking. Then refer to diagnosis
table 2.
6. Switch OFF main power supply. Then release back JW001 and JW002 to original condition (no short
circuit condition).
* If step No. 6 is not carried out, the system will not operate properly until 3 minutes has lapsed after
restore the power supply.
In case of service person forgot to release JW001 and JW002 to original condition;
Case 1:
If main power supply continuously ON, outdoor microcomputer will keep showing diagnosis result (LD303 will
ON and LD301 will blinks).
Case 2:
If main power supply OFF at once, then switch ON again:
a) Outdoor microcomputer will wait the self check command (by pressing test/service switch) within 3 minutes
(LD302 blinks 1 time).
If test/service signal input is not received, unit will return to normal operation mode after this 3 minutes has
lapsed. (LD302 OFF and LD301 blinks 1 time).
Case 3:
If main power supply OFF at once, then switch ON again and on indoor unit by remote control;
a) Indoor unit will receive remote control signal and send signal to outdoor unit. For the first 3 minutes, outdoor
micro-computer will ignore this indoor signal (LD302 blinks 1 time).
b) After 3 minutes has lapsed (LD302 OFF and LD301 blinks 1 time), unit will return to normal operation mode.