Mitsubishi Electric PUHZ-RP250YHA2 Service Manual page 30

<Abnormalities detected while unit is operating>
Abnormal point and detection method
Error Code
High pressure (High-pressure switch
63H(RP200)/63H1 or 63H2(RP250)
worked)
Abnormal if high-pressure switch
63H(RP200)/63H1 or 63H2(RP250) worked
( ) during compressor operation.
63H1: 4.15 MPa
63H, 63H2: 3.6 MPa
63H, 63H1, 63H2: High-pressure switch
U1
(1302)
High discharging temperature
(1) Abnormal if discharge temperature ther-
mistor (TH4) exceeds 125
continuously for 5 minutes.
Abnormal if condenser/evaporator tem-
perature thermistor (TH5) exceeds 40
during defrosting and discharge temper-
ature thermistor (TH4) exceeds 110 .
U2
(2) Abnormal if discharge superheat
(1102)
(Cooling: TH4 – TH5 / Heating: TH4 –
TH6) exceeds 70
minutes.
Open/short circuit of discharge
temperature thermistor (TH4)
Abnormal if open (3
(217 or more) is detected during
compressor operation.
(Detection is inoperative for 10 minutes
of compressor starting process and for 10
minutes after and during defrosting.)
U3
(5104)
Short cycle of indoor unit
Clogged filter of indoor unit
Decreased airflow caused by
dirt of indoor fan
Dirt of indoor heat exchanger
Locked indoor fan motor
Malfunction of indoor fan motor
Defective operation of stop
valve (Not fully open)
Clogged or broken pipe
Locked outdoor fan motor
Malfunction of outdoor fan
motor
Short cycle of outdoor unit
Dirt of outdoor heat exchanger
Decreased airflow caused by
defective inspection of outside
temperature thermistor
(It detects lower temperature
than actual temperature.)
Disconnection or contact failure
of connector (63H) on outdoor
controller board
Disconnection or contact failure
of 63H connection
Defective outdoor controller
board
Defective action of linear
expansion valve
Malfunction of fan driving
circuit
Overheated compressor opera-
tion caused by shortage of
or 110
refrigerant
Defective operation of stop
valve
Defective thermistor
Defective outdoor controller
board
Defective action of linear
expansion valve
continuously for 10 Clogging with foreign objects in
refrigerant circuit
Clogging occurs in the parts
which become below freez-
ing point when water enters in
refrigerant circuit.
Disconnection or contact
failure of connector (TH4) on
the outdoor controller circuit
or less) or short
board
Defective thermistor
Defective outdoor controller
circuit board
Case
~ Check indoor unit and repair defect.
Check if stop valve is fully open.
Check piping and repair defect.
~ Check outdoor unit and repair defect.
Check the inspected temperature of outside
temperature thermistor on LED display.
(SW2 on A-Control Service Tool : Refer to
10-10.)
~ Turn the power off and check F5 is
displayed when the power is turned again.
When F5 is displayed, refer to "Judgment
and action" for F5.
Check linear expansion valve.
Refer to 10-7.
Replace outdoor controller board.
Check intake superheat.
Check leakage of refrigerant.
Charge additional refrigerant.
Check if stop valve is fully open.
Turn the power off and check if U3 is dis-
played when the power is turned on again.
When U3 is displayed, refer to "Judgement
and action" for U3.
Check linear expansion valve.
Refer to 10-7.
After recovering refrigerant, remove water
from entire refrigerant circuit under vacuum
more than 1 hour.
Check connection of connector (TH4) on the
outdoor controller circuit board.
Check breaking of the lead wire for
thermistor (TH4). Refer to 10-9.
Check resistance value of thermistor (TH4) or
temperature by microcomputer.
(Thermistor/TH4: Refer to 10-7.)
(SW2 on A-Control Service Tool: Refer to
10-10.)
Replace outdoor controller board.
30
Judgment and action