Mitsubishi Electric PUZ-HA30NHA5 Service Manual page 28

<Abnormalities detected while unit is operating> <Abnormalities detected while unit is operating>
Abnormal point and detection method
Check code
High pressure (High-pressure switch
63H worked)
Abnormal if high-pressure switch 63H
worked (*) during compressor operation.
*602 PSIG [4.15 MPa]
63H: High pressure switch
U1
(1302)
High discharge temperature
(1) Abnormal if discharge temperature
thermistor (TH4) exceeds 257˚F
[125:] or 230˚F [110:] continuously
for 5 minutes.
Abnormal if condenser/evaporator
temperature thermistor (TH5) exceeds
104˚F [40:] during defrosting and
discharge temperature thermistor (TH4)
U2
exceeds 230˚F [110:].
(1102)
(2) Abnormal if discharge superheat
(Cooling: TH4−TH5/Heating: TH4−TH6)
exceeds 126˚F [70:].
Open/short circuit of discharge
temperature thermistor (TH4)
Abnormal if open (37˚F [3:] or less) or
short (422˚F [217:] or more) is detected
during compressor operation.
(Detection is inoperative for 10 minutes
of compressor starting process and for 10
U3
minutes after and during defrosting.)
(5104)
OCH607
Case
1 Short cycle of indoor unit
2 Clogged filter of indoor unit
3 Decreased airflow caused by
dirt of indoor fan
4 Dirt of indoor heat exchanger
5 Locked indoor fan motor
6 Malfunction of indoor fan motor
7 Defective operation of stop
valve (Not full open)
8 Clogged or broken pipe
9 Locked outdoor fan motor
0 Malfunction of outdoor fan
motor
1 Short cycle of outdoor unit
2 Dirt of outdoor heat exchanger
3 Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
4 Disconnection or contact failure
of connector (63H) on outdoor
controller board
5 Disconnection or contact failure
of 63H connection
6 Defective outdoor controller
board
7 Defective action of linear
expansion valve
8 Malfunction of fan driving
circuit
1 Overheated compressor opera-
tion caused by shortage of
refrigerant
2 Defective operation of stop
valve
3 Defective thermistor
4 Defective outdoor controller
board
5 Defective action of linear
expansion valve
6 Clogging with foreign objects in
refrigerant circuit.
Note: logging occurs in the parts
which become below
freezing point when water
enters in the refrigerant
circuit.
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
28
Judgment and action
1–6 Check indoor unit and repair defect.
7 Check if stop valve is fully open.
8 Check piping and repair defect.
9–2 Check outdoor unit and repair defect.
3 Check the detected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer
to "10-10. FUNCTION OF SWITCHES,
CONNECTORS AND JUMPERS". )
4–6 Turn the power off and check F5 is
displayed when the power is on again.
When F5 is displayed, refer to "Judgment
and action" for F5.
7 Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS".
8 Replace outdoor controller board.
1 Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
2 Check if stop valve is fully open.
34 Turn the power off and check if U3 is dis-
played when the power is on again.
When U3 is displayed, refer to "Judgment
and action" for U3.
5 Check linear expansion valve.
Refer to "10-6. HOW TO CHECK THE
PARTS".
6 After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
1 Check connection of connector (TH4) on the
outdoor controller circuit board.
Check breaking of the lead wire for ther-
mistor (TH4). Refer to "10-9. TEST POINT
DIAGRAM".
2 Check resistance value of thermistor
(TH4) or temperature by microcomputer.
(Thermistor/TH4: Refer to "10-6. HOW TO
CHECK THE PARTS".) (SW2 on A-Control
Service Tool: Refer to "10-10. FUNCTION
OF SWITCHES, CONNECTORS AND
JUMPERS".)
3 Replace outdoor controller board.