Mitsubishi Electric Mr.Slim MUZ-FD09NA Service Manual page 21

No. Symptom LED indication
Outdoor unit 7-time fl ash
operates. 2.5 seconds OFF
18
8-time fl ash
2.5 seconds OFF
19
9-time fl ash
2.5 seconds OFF
20
Abnormal point/
Condition
Low discharge tem- Temperature of discharge temperature thermistor has been
perature protection 122°F (50°C) or less for 20 minutes.
PAM protection The overcurrent fl ows into IGBT (Insulated Gate Bipolar tran-
PAM: Pulse Ampli- sistor : TR821) or the bus-bar voltage reaches 320 V or more,
tude Modulation PAM stops and restarts.
Inverter check mode The connector of compressor is disconnected, inverter check
mode starts.
Condition
21
Correspondence
• Refer to 10-5. "Check of LEV".
• Check refrigerant circuit and refrig-
erant amount.
This is not malfunction. PAM protec-
tion will be activated in the following
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 10-5. "How to check in-
verter/compressor".