Mitsubishi Electric Mr.Slim PUHZ-SHW230YKA2, Руководство по обслуживанию

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20
OCH594B
Abnormal point and detection method Case Judgment and action
U5
Temperature of heat sink
Abnormal if heat sink thermistor (TH8)
detects 95
:
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 the thermistor (TH8) temperature by
microprocessor. (SW2 on A-Control Service
Tool: Refer to "8-7. TEST POINT DIAGRAM".)
6
Replace outdoor power circuit board.
7
Replace outdoor controller circuit board.
U4
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, TH32
and TH6 is inoperative for 10 seconds to
10 minutes after compressor starting and
10 minutes after and during defrosting.
Notes: 1. Check which unit has abnormality in
its thermistor by switching the mode of
SW2. (PAC-SK52ST) (Refer to "8-7.
TEST POINT DIAGRAM".)
2. Heat sink thermistor (TH8) is in the
power module. (YKA2/YKA2R1)
1
Check connection of connector (TH3, TH32,
TH7/6) on the outdoor controller circuit board.
Check connection of connector (CN3) on the
outdoor power circuit board. Check break-
ing of the lead wire for thermistor (TH3, TH32,
TH6,TH7,TH8).
Refer to "8-7. TEST POINT DIAGRAM".
2
Check resistance value of thermistor (TH3, TH32,
TH6,TH7,TH8) or check temperature by micro-
processor. (Thermistor/TH3,TH6,TH7,TH32,TH8:
Refer to "8-5. HOW TO CHECK THE PARTS".)
(SW2 on A-Control Service Tool: Refer to "8-8.
FUNCTION OF SWITCHES, CONNECTORS
AND JUMPERS".)
3
Replace outdoor controller circuit board.
1
Disconnection or contact failure
of connectors
Outdoor controller circuit board:
TH3, TH32, TH7/6
Outdoor power circuit board:
CN3
2
Defective thermistor
3
Defective outdoor controller
circuit board
( )
U6
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 "8-7. TEST POINT
DIAGRAM" (Outdoor power circuit board).
4
Check compressor referring to "8-5. HOW TO
CHECK THE PARTS".
5
Replace outdoor power circuit board.
U7
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 "8-6. 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 "8-6. HOW TO CHECK THE COMPONENTS".
Thermistors
Open detection Short detection
Symbol Name
TH3 Thermistor <Liquid> −40°C or below 90°C or above
TH32 Thermistor <Suction> −40°C or below 90°C or above
TH6 Thermistor <2-phase pipe> −40°C or below 90°C or above
TH7 Thermistor <Ambient> −40°C or below 90°C or above
TH8 (YKA2/YKA2R1) Internal thermistor −35°C or below 170°C or above
TH8 (YKA2R2) Thermistor <Heat sink> −34°C or below 102°C or above
U8
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.
3
Replace the outdoor circuit controller board.
(When the failure is still indicated even after
performing the action
1
above.)
Check Code