Mitsubishi Electric SUZ-SWM30VA TH Series Service Manual page 26

10-2. TROUBLESHOOTING CHECK TABLE
No. Symptom LED indication
Outdoor unit 1-time blink eve-
does not ry 2.5 seconds
1 operate.
2
3
6-time blink
2.5 seconds
4
OFF
11-time blink
2.5 seconds
5 OFF
16-time blink
2.5 seconds
6 OFF
20-time blink
7 2.5 seconds
OFF
'Outdoor unit 2-time blink
stops and re- 2.5 seconds OFF
8
starts 3 min-
utes later' is
repeated.
3-time blink
2.5 seconds OFF
9
4-time blink
2.5 seconds OFF
10
5-time blink
11 2.5 seconds OFF
8-time blink
2.5 seconds OFF
12
10-time blink
2.5 seconds OFF
13
12-time blink
14
2.5 seconds OFF
13-time blink
2.5 seconds OFF
15
Outdoor unit 1-time blink
operates. 2.5 seconds OFF
16
3-time blink
2.5 seconds OFF
17
OCH796A
check Abnormal point/
code Condition
Outdoor power Overcurrent protection cut-out operates 3 consecutive
system times within 1 minute after the compressor gets started.
UP
Outdoor thermistors Discharge temperature thermistor shorts, or opens dur-
U3
ing compressor running.
Fin temperature thermistor, defrost thermistor, P.C. board
temperature thermistor, outdoor heat exchanger temperature
U4
thermistor or ambient temperature thermistor shorts, or opens
during compressor running.
Outdoor control Nonvolatile memory data cannot be read properly.
FC
system
Serial signal The communication fails between the indoor and out-
E8/ door unit for 3 minutes.
E9
Stop valve/ Closed valve is detected by compressor current.
Closed valve
UE
Outdoor refrigerant A closed valve and air trapped in the refrigerant circuit
system abnormality are detected based on the temperature sensed by the
PL indoor and outdoor thermistors and the current of the
compressor.
Combination error Abnormal if a connection of indoor unit and outdoor unit
EE with indoor units which uses different refrigerant is detected.
Overcurrent Large current flows into power module (IC700).
protection
Discharge tempera- Temperature of discharge temperature thermistor ex-
ture overheat ceeds
protection 116°C, compressor stops. Compressor can restart if
discharge temperature thermistor reads 100°C or less
3 minutes later.
Fin temperature Temperature of fin temperature thermistor on the heat sink
exceeds 75 ~ 86°C (S(H)WM30/40, SWM60) /75 ~ 80°C
/P.C. board tempera-
ture thermistor over- (SHWM60, SWM80/100) or temperature of P.C. board
heat protection temperature thermistor on the inverter P.C. board exceeds
72 ~ 85°C (S(H)WM30/40, SWM60) /70 ~ 75°C
(SHWM60, SWM80/100).
High pressure Indoor plate heat exchanger thermistor exceeds 70°C
protection in HEAT mode. Defrost thermistor exceeds 70°C in
COOL mode.
Compressor syn- The waveform of compressor current is distorted.
chronous
abnormality
Outdoor fan motor Outdoor fan has stopped 3 times in a row within 30
seconds after outdoor fan startup.
Each phase current Each phase current of compressor cannot be detected
of compressor normally.
Bus-bar voltage Bus-bar voltage of inverter cannot be detected normal-
(DC) ly.
S(H)WM30/40,
Frequency drop by
current protection SWM60
SHWM60
SWM80/100
Frequency drop by Temperature of indoor plate heat exchanger thermistor
high pressure exceeds 60°C in HEAT mode, compressor frequency
protection lowers.
Frequency drop by de- Indoor coil thermistor reads 8°C or less in COOL mode,
frosting in COOL mode compressor frequency lowers.
Condition
When the input current exceeds ap-
proximately 13.2A, compressor fre-
quency lowers.
When the input current exceeds
approximately 17A, compressor
frequency lowers.
26
Remedy
• Reconnect connector of
compressor.
• Refer to 10-5. "How to check
inverter/compressor".
• Check stop valve.
• Refer to 10-5. "Check of outdoor
thermistors".
• Replace inverter P.C. board.
• Check indoor/outdoor connecting
wire.
• Replace indoor or outdoor P.C. board
if abnormality is displayed again.
• Check stop valve.
• Check the amount of refrigerant filled.
• Check water volume and water flow
rate in total system. See indoor unit
IM for correct value.
• Check for a gas leak in a connecting
piping, etc.
• Check stop valve.
• Refer to 10-5. "Check of outdoor
refrigerant circuit".
• Connect a proper unit.
• Check a pressure sensor in indoor
unit.
• Reconnect connector of compressor.
• Refer to 10-5. "How to check
inverter/compressor".
• Check stop valve.
• Check refrigerant circuit and refriger-
ant amount.
• Refer to 10-5. "Check of LEV".
• Check around outdoor unit.
• Check outdoor unit air passage.
• Refer to 10-5. "Check of outdoor
fan motor".
• Check refrigerant circuit and refriger-
ant amount.
• Check stop valve.
• Reconnect connector of
compressor.
• Refer to 10-5. "How to check
inverter/compressor".
• Refer to 10-5. "Check of outdoor
fan motor.
• Refer to 10-5. "Check of inverter
P.C. board.
• Refer to 10-5. "How to check
inverter/compressor".
• It occurs with following case.
Instantaneous power voltage drop.
(Short time power failure) (SHWM60,
SWM80/100)
• Refer to 10-5. "Check of power
supply". (SHWM60, SWM80/100)
• Refer to 10-5. "How to check
inverter/compressor".
The unit is normal, but check the fol-
lowing.
• Check if indoor filters are clogged.
• Check if refrigerant is short.
• Check if indoor/outdoor unit air circu-
lation is short cycled.