Mitsubishi Electric Mr.Slim PUZ-HA30NHA2 Service Manual page 28

Error Code Abnormal point and detection method
Open/short circuit of discharge
temperature thermistor (TH4)
Abnormal if open (3: [37˚F] or less) or
short (217: [422˚F] or more) is detected
U3
during compressor operation.
(5104)
(Detection is inoperative for 10 minutes
of compressor starting process and for 10
minutes after and during defrosting.)
Open/short of outdoor unit thermistors
(TH3, TH32, TH33, TH6, TH7, and TH8)
Abnormal if open or short is detected dur-
ing compressor operation.
Open detection of thermistors
TH3,TH32,TH33 and TH6 is inoperative for
10 seconds to 10 minutes after compressor
starting and 10 minutes after and during
defrosting.
WCheck which unit has abnormality in its
thermistor by switching the mode of SW2.
U4,
(PAC-SK52ST) (Refer to 11-10.)
TH32, TH33
(TH3:5105)
(TH6:5107)
(TH7:5106)
(TH8:5110)
Symbol
TH3,TH32,TH33
TH6
TH7
TH8
Temperature of heatsink
Abnormal if heat sink thermistor(TH8)
detects temperature indicated below.
HA30, 36 ······························ 84:, 183˚F
U5
(4230)
Power module
Check abnormality by driving power mod-
ule in case overcurrent is detected.
(UF or UP error condition)
U6
(4250)
Too low superheat due to low discharge
temperature
Abnormal if discharge superheat is con-
tinuously detected less than or equal to
-15˚C[5˚F] for 3 minutes even though lin-
U7
ear expansion valve has minimum open
(1520)
pulse after compressor starts operating for
10 minutes.
1 Disconnection or contact failure
of connector (TH4) on the out-
door controller circuit board
2 Defective thermistor
3 Defective outdoor controller cir-
cuit board
1 Disconnection or contact failure
of connectors
(
Outdoor controller circuit
board:
TH3, TH32, TH33,TH7/TH6
Outdoor power circuit board:
CN3
2 Defective thermistor
3 Defective outdoor controller cir-
cuit board
Thermistors
Name
Thermistor <Outdoor pipe>
Thermistor <Outdoor 2-phase pipe>
Thermistor <Outdoor>
Thermistor <Heatsink>
1 The outdoor fan motor is locked.
2 Failure of outdoor fan motor
3 Air flow path is clogged.
4 Rise of ambient temperature
5 Defective thermistor
6 Defective input circuit of out-
door power circuit board
7 Failure of outdoor fan drive circuit
1 Outdoor stop valve is closed.
2 Decrease of power supply voltage
3 Looseness, disconnection or
converse of compressor wiring
connection
4 Defective compressor
5 Defective outdoor power circuit
board
1 Disconnection or loose connec-
tion of discharge
temperature thermistor (TH4)
2 Defective holder of discharge
temperature thermistor
3 Disconnection or loose connection
of linear expansion valve's coil
4 Disconnection or loose connec-
tion of linear expansion valve's
connector
5 Defective linear expansion valve
Case
1 Check connection of connector (TH4) on the
outdoor controller circuit board.
Check breaking of the lead wire for thermis-
tor (TH4). Refer to 11-9.
2 Check resistance value of thermistor (TH4)
or temperature by microcomputer.
(Thermistor/TH4: Refer to 11-6.)
(SW2 on A-Control Service Tool: Refer to 11-10.)
3 Replace outdoor controller board.
1 Check connection of connector
(TH3,TH,32,TH33,TH7/6) on the outdoor
controller circuit board.
Check connection of connector (CN3) on the
outdoor power circuit board.
Check breaking of the lead wire for thermis-
tor (TH3,TH32,TH33,TH6,TH7,TH8). Refer
to 11-9.
2 Check resistance value of thermistor (TH3,T
H32,TH33,TH6,TH7,TH8) or check tempera-
ture by microcomputer.
(Thermistor/TH3,TH6,TH7,TH8: Refer to 11-6.)
(SW2 on A-Control Service Tool: Refer to 11-10.)
3 Replace outdoor controller circuit board.
WEmergency operation is available in case of
abnormalities of TH3,TH32,TH33,TH6 and
TH7. Refer to 11-8.
Open detection
– 40 [-40°F] or below
– 40 [-40°F] or below
– 40 [-40°F] or below
– 27 [-17°F] or below
12 Check outdoor fan.
3 Check air flow path for cooling.
4 Check if there is something which causes
temperature rise around outdoor unit.
(Upper limit of ambient temperature is 46:
[114˚F].)
Turn off power, and on again to check if U5
is displayed within 30 minutes.
If U4 is displayed instead of U5, follow the
action to be taken for U4.
5 Check resistance value of thermistor (TH8)
or temperature by microcomputer.
(Thermistor/TH8: Refer to 11-6.)
(SW2 on A-Control Service Tool: Refer to
11-10.)
6 Replace outdoor power circuit board.
7 Replace outdoor controller circuit board.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U·V·W phase) to com-
pressor. Refer to 11-9 (Outdoor power circuit
board).
4 Check compressor referring to 11-6.
5 Replace outdoor power circuit board.
12 Check the installation conditions of dis-
charge temperature thermistor (TH4).
3 Check the coil of linear expansion valve.
Refer to 11-7.
4 Check the connection or contact of LEV-A and
LEV-B on outdoor controller circuit board.
5 Check linear expansion valve.Refer to 11-6.
28
Judgment and action
Short detection
90 [194°F] or above
90 [194°F] or above
90 [194°F] or above
102 [216°F] or above