Mitsubishi Electric PUZ-WM112VAA, Руководство по обслуживанию

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26
OCH727
( )
Check code Abnormal points and detection method Cause judgment and action
U4
(TH3:5105)
(TH6:5107)
(TH7:5106)
(TH8:5110)
(TH34:5105)
Open/short of outdoor unit thermistors
(TH3, TH34, TH6, TH7, and TH8)
Abnormal if open or short is detected during
compressor operation.
Open detection of TH3, TH34 and TH6 is
inoperative for 10 seconds to 10 minutes
after compressor starting and 10 minutes
after and during defrosting.
Note: Check which unit has abnormality in
its thermistor by switching the mode
of SW2. (PAC-SK52ST)
(Refer to "9-7. FUNCTION OF
SWITCHES, CONNECTORS AND
JUMPERS".)
1
Disconnection or contact failure
of connectors
Outdoor controller circuit board:
TH3, TH34, TH7/6
Outdoor power circuit board:
CN3
2
Defective thermistor
3
Defective outdoor controller
circuit board
1
Check connection of connector (TH3, TH34,
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 TH3, TH34, TH6, TH7, TH8.
Refer to "9-6.TEST POINT DIAGRAM".
2
Check resistance value of TH3, TH34,
TH6,TH7,TH8 or check temperature by
microprocessor. (TH3,TH34,TH6,TH7,TH8:
Refer to "9-6.TEST POINT DIAGRAM".) (SW2
on A-Control Service Tool: Refer to "9-7.
FUNCTION OF SWITCHES, CONNECTORS
AND JUMPERS".)
3
Replace outdoor controller circuit board.
Note: Emergency operation is available in case
of abnormalities of TH3, TH34, TH6 and
TH7.
U5
(4230)
Temperature of heat sink
Abnormal if TH8 detects temperature indi-
cated below.
WM50V··············································77
:
WM60V,WM85V,WM112V ·················78
:
WM85Y,WM112Y ·······························85
:
TH8: Thermistor <Heat sink>
1
The outdoor fan motor is locked.
2
Failure of outdoor fan motor
3
Airflow 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
12
Check outdoor fan.
3
Check airflow path for cooling.
4
Check if there is something which causes
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.
5
Check resistance value of TH8 or temperature
by microprocessor. (TH8: Refer to
"9-4. HOW TO CHECK THE PARTS".)
(SW2 on A-Control Service Tool: Refer to "9-7.
FUNCTION OF SWITCHES, CONNECTORS
AND JUMPERS". )
6
Replace outdoor power circuit board.
7
Replace outdoor controller circuit board.
U6
(4250)
Power module
Check abnormality by driving power module
in case overcurrent is detected.
(UF or UP error condition)
1
Outdoor stop valve is closed.
2
Decrease of power supply voltage
3
Looseness, disconnection or reverse
of compressor wiring connection
4
Defective compressor
5
Defective outdoor power circuit board
1
Open stop valve.
2
Check facility of power supply.
3
Correct the wiring (U
•
V
•
W phase) to compressor. Refer to
"9-6.TEST POINT DIAGRAM" (Outdoor power circuit board).
4
Check compressor referring to "9-4. HOW TO
CHECK THE PARTS".
5
Replace outdoor power circuit board.
U7
(1502)
Too low superheat due to low discharge
temperature
Abnormal if discharge superheat is
continuously detected less than or equal
to −15
:
for 3 minutes even though linear
expansion valve has minimum open pulse
after compressor starts operating for 10
minutes.
1
Disconnection or loose
connection 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 connection of
linear expansion valve’s connector
5
Defective linear expansion valve
12
Check the installation conditions of
discharge temperature thermistor (TH4).
3
Check the coil of linear expansion valve.
Refer to "9-5. HOW TO CHECK THE
COMPONENTS".
4
Check the connection or contact of LEV-A and
LEV-B on outdoor controller circuit board.
5
Check linear expansion valve. Refer to "9-4.
HOW TO CHECK THE PARTS".
U8
(4400)
Outdoor fan motor
Abnormal if rotational frequency of the fan motor
is not detected during DC fan motor operation.
Fan motor rotational frequency is abnormal if;
• 100 rpm or below detected continuously
for 15 seconds at 20
:
or more outside
air temperature.
• 50 rpm or below or 1500 rpm or more
detected continuously for 1 minute.
1
Failure in the operation of the
DC fan motor
2
Failure in the outdoor circuit
controller board
1
Check or replace the DC fan motor.
2
Check the voltage of the outdoor circuit
controller board during operation.
(When the failure is still indicated even after
performing the action
1
above.)
Thermistors
Open detection Short detection
Symbol Name
TH3 Thermistor <Liquid> −40 °C or below 90 °C or above
TH6 Thermistor <Two-phase> −40 °C or below 90 °C or above
TH7 Thermistor <Ambient> −40 °C or below 90 °C or above
TH8 Thermistor <Heat sink> −35 °C or below 102 °C or above
TH34 Thermistor <Plate hex liquid> −40 °C or below 90 °C or above