<Abnormality detected during unit operation: Outdoor-side unit>
Abnormal-
ity display
U2
U3
U4
U6
Meaning of abnormality display and
abnormality troubleshooting
Discharge temperature abnormal
When the discharge thermistor tem-
perature (TH2) exceeds 118
°
C while
the compressor is operating, an ab-
normality is recognized.
49C trip (CN23 connector discon-
nected)
When connector CN23 opens while
the compressor is operating, an ab-
normality is recognized.
Discharge temp thermistor (TH2)
open or shorted.
When an open (0
°
C or lower) or
short (216
°
C or higher) is detected
while the compressor is operating, an
abnormality is recognized.
(Detection is disabled for 5 minutes
at compressor starting.)
Liquid temp thermistor (TH1) or
condenser/evaporater temp ther-
mistor (TH3) open or shorted.
When an open (–39
°
C or lower) or
short (88
°
C or higher) is detected
while the compressor is operating, an
abnormality is recognized. (Detection
is disabled for 7 minutes beginning
from 10 seconds after the compres-
sor starts and for 10 minutes after
return from defrosting.)
Compressor overcurrent trip
When the current value reaches the
overload set value or higher while the
compressor is operating, an abnor-
mality is recognized.
P8MYA .................................. 22 A
27 A
22 A x 2 pcs.
P10MYA ................................
P16MYA ...................
27 A x 2 pcs.
P20MYA ...................
Cause
(1) Compressor overheating due to insuf-
ficient refrigerant.
(2) Thermistor faulty. (TH2)
(3) Outdoor-side controller board faulty.
(1) Shorting connector CN23 on
outdoor-side controller board
dislodged or contact faulty.
(1) Connector (CN3) dislodged or con-
nect faulty.
(2) Thermistor faulty.
(3) Outdoor-side controller board faulty.
(1) Connector (TH1: CN2, TH3: CN4) dis-
lodged or contact faulty.
(2) Thermistor faulty.
(3) Outdoor-side controller board faulty.
(1) Overload operation exceeding unit us-
age range limit.
(2) Power supply terminal voltage low.
(3) Power supply missing phase.
(4) Compressor motor faulty.
(5) Compressor locked.
(6) Connector (CN23) on outdoor-side
controller board dislodged or
contact faulty.
(7) 51C
(8) Liquefied refrigerant gas entering
and accumulating in the compressor
disconnected or contact faulty.
Judgment method and remedy
(1) Check input super heat.
Check for refrigerant leakage and
check piping length.
Charge with additional refrigerant.
(2)(3)
Turn off power and restart operation
and check if U3 is displayed within 8
minutes.
When U3 is displayed, carry out U3 pro-
cessing.
(Do not replace board at U2 display
only.)
(1) Repair shorting connector.
(1) Check connector contact and ther-
mistor wire.
(2) Check thermistor resistance value, or
check temperature by microcomputer.
(Check using SW2 self-diagnosis func-
tion.)
See page 54.
(3) Replace outdoor-side controller board.
(Replace board after sufficiently check-
ing 1 and 2.)
(1) Check connector contact and ther-
mistor wire.
(2) Check thermistor resistance value or
check temperature by microcomputer.
(Check using SW2 self-diagnosis func-
tion.)
See to page 54.
(3) Replace outdoor-side controller board.
(Replace board after sufficiently check-
ing 1 and 2)
(1) Check usage conditions.
(Check for short cycle operation.)
(2) Check power supply voltage.
(3) Check wiring for breaks and faulty con-
tact.
(4) Check motor winding resistance (See
page 53.)
(5) Replace
(8) Absence of energization in the
crankcase heater
compressor.
(6)(7)
After checking connections, restart and
check operation.
UE
High Pressure Abnormality (63H1
operation)
Considered abnormal when 63H1
goes into operation during compres-
sor operation (3.3 MPa or above)
63H1:Pressure switch (High Pres-
sure)
OFF:3.3 (MPa)
ON :2.65
±
0.2(MPa)
(1) Short cycle on the indoor-side
(2) Clogged filter on the indoor-side
(3) Reduced air flow on the indoor-side
due to dirty fan
(4) Dirty heat exchanger on the indoor-
side
(5) Fan motor lock on the indoor-side
(6) Fan motor malfunction on the indoor-
side
(7) Clogged or broken pipe
(1)~(6):During heating operation
Check the unit on the indoor-side,
and correct the problems.
(7) Check the piping, and correct the
problems.
+0
-0.15
+0
-0.15
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