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7
Service and Maintenance
Code
Error
Too low superheat due to low
discharge temperature
Abnormal if discharge superheat is
continuously detected less than or
equal to −15°C for 3 minutes even
U7
though linear expansion valve
(1520)
has minimum open pulse after
compressor starts operating for 10
minutes.
U9
Abnormal voltage error
(4220)
See service handbook.
Abnormal pressure of 63HS
Abnormal if 63HS detects 0.1 MPa
or less.
Detection is inoperative for 3 min-
UE
utes after compressor starting and
(1302)
3 minutes after and during defrost-
ing.
63HS: High pressure sensor
Low pressure
Abnormal if TH33-TH4 exceeds
UL
20°C and TH33 exceeds 80°C dur-
(1300)
ing compressor operation.
Compressor overcurrent inter-
ruption
(When compressor locked)
UF
Abnormal if overcurrent of DC bus
(4100)
or compressor is detected within
30 seconds after compressor
starts operating.
Current sensor error or input
current error
• Abnormal if current sensor de-
tects –1.0A to 1.0A during com-
UH
pressor operation. (This error is
(5300)
ignored in case of test run mode.)
• Abnormal if 40A of input current
is detected or 37A or more of
input current is detected for 10
seconds continuously.
Low ambient loop flow rate (flow
switch operated)
Abnormal if flow switch is operated
(under 5.5L/min) during compres-
sor operation.
UA
(2511)
Compressor overcurrent inter-
ruption
UP
Abnormal if overcurrent DC bus
(4210)
or compressor is detected after
compressor starts operating for 30
seconds.
Cause
1 Disconnection or loose connection
of discharge temperature thermistor
(TH4)
2 Defective holder of discharge tempera-
ture 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
See service handbook.
1 Disconnection or contact failure of
connector (63HS) on the C.B.
2 Defective pressure sensor
3 Defective C.B.
1 Defective linear expansion valve.
2 Defective C.B.
1 Decrease of power supply voltage
2 Looseness, disconnection or converse
of compressor wiring connection
3 Defective compressor
4 Defective power circuit board
1 Disconnection of compressor wiring
2 Defective circuit of current sensor on
power circuit board
3 Decrease of power supply voltage
4 Leakage or shortage of refrigerant
1 Valve or PICV of ambient loop circuit is
closed during operation.
2 Disconnection or loose connection of
connector (63L) on C.B.
3 Disconnection or loose connection of
63L
4 Defective C.B.
5 Leakage or shortage of water or brine
(Ambient loop)
6 Misconnection of Water/Brine pipe.
See service handbook.
Action
12 Check the installation conditions of dis-
charge temperature thermistor (TH4).
3 Check the coil of linear expansion valve.
4 Check the connection or contact of LEV-
A on C.B.
5 Check linear expansion valve.
See service handbook.
1 Check connection of connector (63HS)
on the C.B.
Check breaking of the lead wire for
63HS.
2 Check pressure by microprocessor.
(Pressure sensor/ 63HS)
3 Replace C.B.
1 Check linear expansion valve.
2 Replace C.B.
1 Check facility of power supply.
2 Correct the wiring (U•V•W phase) to
compressor.
3 Check compressor.
4 Replace power circuit board.
1 Correct the wiring (U•V•W phase) to
compressor.
2 Replace power circuit board.
3 Check the facility of power supply.
4 Check leakage of refrigerant.
1 Check valve or PICV.
Active SW6-4 on FTC, if TBI.4 7-8 is
connected.
2 - 4 Turn the power off and on again to
check if F3 is displayed on restarting.
If F3 is displayed, follow the F3
processingdirection.
5 Correct to proper amount of water or
brine.
6 Check Water/Brine pipe connection.
See service handbook.
en
50
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