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45
TROUBLESHOOTING
This unit has on−board diagnostics. Error codes are displayed on the wired remote controller and the outdoor unit microprocessor board with
colored LED lights. Table 42 explains the error codes on both.
Sizes 18 and 24
Table 42—Malfunction Status Table
MALFUNCTION NAME
MALFUNCTION TYPE
NIXIE
TUBE
Zero cross detection circuit malfunction (for indoor unit)
Hardware malfunction
U8
Malfunction protection of jumper cap (for indoor unit)
Hardware malfunction
C5
Feedback of without IDU motor(for indoor unit)
Hardware malfunction
H6
Indoor ambient temperature sensor is open/short circuited
Hardware malfunction
F1
Indoor evaporator temperature sensor is open/short circuited
Hardware malfunction
F2
Liquid valve temperature sensor is open/short circuited
Hardware malfunction
b5
Gas valve temperature sensor is open/short circuited
Hardware malfunction
b7
Modular temperature sensor is open/short circuited
Hardware malfunction
P7
Outdoor ambient temperature sensor is open/short circuited
Hardware malfunction
F3
Outdoor condenser middle pipe temperature sensor is
open/short circuited
Hardware malfunction
F4
Outdoor discharge temperature sensor is open/short circuited
Hardware malfunction
F5
Communication malfunction
Hardware malfunction
E6
Malfunction of phase current detection circuit for compressor
Hardware malfunction
U1
Module high temperature protection
Viewing malfunction code through remote controller within 200s;
displayed directly on nixie tube after 200s
P8
Refrigerant lacking or blockage protection of system (not
available for residential ODU)
F0
Charging malfunction of capacitor
Hardware malfunction
PU
High pressure protection of system
Hardware malfunction
E 1
Low pressure protection of system (reserved)
Hardware malfunction
E3
Compressor overload protection
Viewing malfunction code through remote controller within 200s;
displayed directly on nixie tube after 200s
H3
Indoor unit and outdoor unit do not match
Hardware malfunction
LP
Malfunction of memory chip
Hardware malfunction
E E
Wrong connection of communication wire or malfunction of
electronic expansion valve
Hardware malfunction
dn
Malfunction protection of outdoor fan 1
Hardware malfunction
L3
Detection status of wrong connection of communication wire or
malfunction of electronic expansion valve
Operation status
dd
Mode conflict
Operation status
E7
Refrigerant recycling mode
Operation status
Fo
X-fan
Operation status
AL
Defrosting or oil return in heating mode
Operation status
H 1
Start failure of compressor
Viewing malfunction code through remote controller within 200s;
displayed directly on nixie tube after 200s
Lc
High discharge temperature protection of compressor
E4
Overload protection
E8
Whole unit over-current protection
E5
Compressor phase current protection
P5
Compressor de-synchronizing
H7
Compressor phase-lacking/phase-inverse protection
Ld
IPM modular protection
H5
DC bus-bar low voltage protection
PL
DC bus-bar high voltage protection
PH
PFC protection
HC
The four-way valve is abnormal
U7