Mitsubishi Electric SUZ-SWM30VA TH Series Service Manual page 27

No. Symptom LED indication
Outdoor unit 4-time blink
operates. 2.5 seconds OFF
18
S(H)WM30/40,
SWM60
19
5-time blink
2.5 seconds OFF
7-time blink
20 2.5 seconds OFF
8-time blink
2.5 seconds OFF
21
9-time blink
2.5 seconds OFF
22
NOTE: 1. The location of LED is illustrated at the right figure. Refer to 10-6.
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
2.5-second OFF
OFF
10-3. HOW TO PROCEED "SELF-DIAGNOSIS
Refer to "TROUBLE SHOOTING" of the indoor unit service manual.
OCH796A
Abnormal point/
Condition
Frequency drop by Temperature of discharge temperature thermistor exceeds
discharge tempera- 111°C, compressor frequency lowers.
ture protection
Outside temperature When the outside temperature thermistor shorts or opens, pro-
thermistor protection tective operation without that thermistor is performed.
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 50°C or less for 20 minutes.
S(H)WM30/40/ The overcurrent flows into IGBT(Q821) or the bus-bar voltage
SWM60 reaches 394 V or more, PAM stops and restarts.
PAM protection PAM:
Pulse Amplitude
Modulation
SHWM60
Zero cross signal cannot be detected.
SWM80/100
Zero cross detecting
circuit
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
0.5-second ON
2.5-second OFF
27
Condition
0.5-second ON
Remedy
• Check refrigerant circuit and refrig-
erant amount.
• Refer to 10-5. "Check of LEV".
• Refer to 10-5. "Check of outdoor
thermistors".
• Refer to 10-5. Check of outdoor
thermistors.
• Refer to 10-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
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.
• It occurs with following cases.
1 Instantaneous power voltage
drop. (Short time power failure)
2 Distortion of primary voltage
• Refer to 10-5. "Check of power
supply".
• Check if the connector of the com-
pressor is correctly connected.
Refer to 10-5. "How to check
inverter/compressor".
Inverter P.C. board
LED
Blinking →