Lennox LIUH018021T431E-1 Service Manual page 123

T3 temperature sensor open or short circuit
T5 temperature sensor open or short circuit
Outdoor EEPROM malfunction (for some units)
Outdoor fan speed malfunction
T2B temperature open or short circuit (for free-match indoor units)
Communication error between auto-lifting panel and slim cassette
Auto-lifting panel is faulty (for slim cassettes with an auto-lifting panel)
Auto-lifting panel is not closed (for slim cassettes with an auto-lifting
panel)
IPM module malfunction
DC voltage too high/too low protection
High temperature protection of compressor top
Low ambient temperature protection
Inverter compressor drive protection
Compressor low pressure protection
Outdoor IGBT sensor is faulty
2.3 Outdoor Unit Malfunctions
For 18~60K:
Display
E1 Communication malfunction between indoor and outdoor units
F0 Overcurrent protection
F1 Ambient temperature sensor (T4) malfunction
F2 Outdoor heat-exchanger temperature sensor (T3) malfunction
F3 Discharge temperature sensor (T5) malfunction
F4 Outdoor EEPROM malfunction
F5 Outdoor fan speed malfunction
P0
IPM module protection
P1 DC voltage too high/too low protection
P2 High temperature protection of compressor top
P3 Ultra-low ambient temperature protection
P4 Compressor rotor position protection
J0 Evaporator high temperature protection
J1 Condenser high temperature protection
J2 High discharge temperature protection
J3 PFC module protection
J4 Communication error between outdoor main chip and compressor driven chip
J5 High pressure protection
J6 Low pressure protection
P7 IGBT sensor malfunction
J8 AC power input voltage protection
In low ambient cooling mode, the LED displays " LC" or alternates between running frequency and "LC" (each
appears for 0.5s).
Electrical Control System
O (on) X(off) ☆(flash at 2Hz)
Malfunction or Protection
F2 O
F3 O
F4 O
F5 O
F6 O
F7 O
F8 O
F9 O
P0
☆
P1 ☆
P2
☆
P3 ☆
P4
☆
P6 ☆
P7
☆
Troubleshooting
3
4
5
6
7
8
9
10
1
2
3
4
5
7
8
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