33
No.
Symptom
LED indication
Abnormal point/
Condition
Condition
Remedy
20
MUZ-RW25/35
5-time blink
2.5 seconds OFF
Outside temperature
thermistor protection
When the outside temperature thermistor shorts or opens, pro-
tective operation without that thermistor is performed.
• Refer to 12-5. Check of outdoor
thermistors.
21
Outdoor unit
operates.
7-time blink
2.5 seconds OFF
Low discharge tem-
perature protection
Temperature of discharge temperature thermistor has been
50°C or less for 20 minutes.
• Refer to 12-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
22
8-time blink
2.5 seconds OFF
MUZ-RW25/35
PAM protection PAM:
Pulse Amplitude
Modulation
The overcurrent flows into IGBT(Q821) or the bus-bar voltage
reaches 394 V or more, PAM stops and restarts.
This is not malfunction. PAM
protection will be activated in the
following cases:
1 Instantaneous power voltage
drop. (Short time power failure)
2 When the power supply voltage
is high.
MUZ-RW50
Zero cross detecting
circuit
Zero cross signal cannot be detected.
• It occurs with following cases.
1 Instantaneous power voltage
drop. (Short time power failure)
2 Distortion of primary voltage
• Refer to 12-5. "Check of power
supply".
23
9-time blink
2.5 seconds OFF
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
• Check if the connector of the com-
pressor is correctly connected.
Refer to 12-5. "How to check
inverter/compressor".
NOTE:
1. The location of LED is illustrated at the right figure. Refer to 12-6.1.
2. LED is lit during normal operation.
The blinking frequency shows the number of times the LED blinks after every 2.5-second OFF.
(Example) When the blinking frequency is "2".
ON
OFF
2.5-second OFF
2.5-second OFF
0.5-second ON
0.5-second ON
LED
Blinking →
MUZ-RW25/35VGHZ
Inverter P.C. board
MUZ-RW50VGHZ
LED
Blinking →
OBH903
