Mitsubishi Electric MUZ-HJ25VA-E2 Service Manual page 42

No. Symptom LED indication
Outdoor unit 7-time fl ash
21 operates. 2.5 seconds OFF
8-time fl ash
2.5 seconds OFF
22
9-time fl ash
2.5 seconds OFF
23
NOTE: 1. The location of LED is illustrated at the right fi gure. Refer to 11-6.1.
2. LED is lighted during normal operation.
The fl ashing frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the fl ashing frequency is "2".
ON
2.5-second OFF
OFF
OBH648F
Abnormal point/
Condition
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 50°C or less for 20 minutes.
PAM protection The overcurrent fl ows into IC821 (Switching power transistor)
PAM: Pulse Ampli- (HJ25/35)/IC820 (Power module) (HJ50/60/71) or the bus-bar
tude Modulation voltage reaches 320 V or more, PAM stops and restarts.
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
0.5-second ON
2.5-second OFF
Condition
0.5-second ON
42
Remedy
• Refer to 11-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
This is not malfunction. PAM pro-
tection will be activated in the fol-
lowing cases:
1 Instantaneous power voltage
drop. (Short time power failure)
2 When the power supply voltage
is high.
• Check if the connector of the com-
pressor is correctly connected.
Refer to 11-5. "How to check
inverter/compressor".
Inverter P.C. board
LED
←
Flashing