Mitsubishi Electric PUHZ-RP8YHA Technical & Service Manual page 35

Error Code Meaning of error code and detection method
Open/short circuit of discharge
temperature thermistor (TH4)
Abnormal if open (3: or less) or short
(217: or more) is detected during
U3
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, TH6, TH7, and TH8)
Abnormal if open or short is detected
during compressor operation.
Open detection of thermistors TH3 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
U4
thermistor by switching the mode of
)
( TH3, TH32
SW2.
:5105
(Refer to page 62.)
(TH6:5107)
(TH7:5106)
(TH8:5110)
Symbol
TH3, TH32
Thermistor <Outdoor 2-phase pipe>
TH6
TH7
TH8
Abnormal temperature of heat sink
Abnormal if heat sink thermistor TH8,
which is built in the power module, detects
temperature indicated below.
RP8YHA ...... 95:
RP10YHA .... 95:
U5
(4230)
Compressor overcurrent interruption
(When compressor locked)
Abnormal if overcurrent of DC bus or
compressor is detected within 30 seconds
after compressor starts operating.
Abnormality of power module
Check abnormality by driving power module
in case overcurrent is detected.
U6
(4250)
1 Disconnection or contact
failure of connector (TH4) on
the outdoor controller circuit
board.
2 Defective thermistor.
3 Defective outdoor controller
circuit board.
1 Disconnection or contact failure
of connectors.
Outdoor controller circuit
(
board: TH3, TH32, TH6/TH7
Outdoor power circuit board:
CN3
2 Defective thermistor.
3 Defective outdoor controller
circuit board.
Thermistors
Name
Thermistor <Outdoor pipe>
Thermistor <Outdoor>
Internal thermistor
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
outdoor power circuit board.
7 Failure of outdoor fan drive
circuit.
1 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 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.
Case
1 Check connection of connector (TH4) on the
2 Check resistance value of thermistor (TH4) or
3 Replace outdoor controller circuit board.
1 Check connection of connector (TH3, TH32,
)
2 Check resistance value of thermistor (TH3,
3 Replace outdoor controller circuit board.
WEmergency operation is available in case of
Open detection
– 40: or below
– 40: or below
– 40: or below
– 35: or below
12 Check the resistance of outdoor fan motor
3 Check air flow path for cooling.
4 Check if there is something which causes
5 Check TH8 temperature by microcomputer.
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
4 Check compressor.
5 Replace outdoor power circuit board.
1 Open stop valve.
2 Check facility of power supply.
3 Correct the wiring (U•V•W phase) to
4 Check compressor referring to 13-6.
5 Replace outdoor power circuit board.
35
Judgment and action
outdoor controller circuit board.
Check breaking of the lead wire for
thermistor (TH4). Refer to 13-9.
temperature by microcomputer.
(Thermistor/TH4: Refer to 13-6.)
(SW2 on A-Control Service Tool: Refer to
page 57.)
TH6/TH7) on the outdoor controller circuit board.
Check connection of connector (CN3) on the
outdoor power circuit board.
Check breaking of the lead wire for thermistor
(TH3, TH32, TH6,TH7,TH8). Refer to 13-9.
TH32, TH6,TH7,TH8) or check temperature
by microcomputer.
(Thermistor/TH3,TH32,TH6,TH7,TH8: Refer to13-6.)
(SW2 on A-Control Service Tool: Refer to
page 57.)
abnormalities of TH3, TH32, TH6 and TH7.
Refer to 13-8.
Short detection
90: or above
90: or above
90: or above
170: or above
wiring.
Refer to "13-6 HOW TO CHECK THE PART".
temperature rise around outdoor unit.
(Upper limit of ambient temperature is 46:.)
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.
(SW2 on A-Control Service Tool: Refer to
page 57.)
compressor.
Refer to page 52 and 53.
Refer to 13-6.
compressor. Refer to 13-9.