Lennox LIUH018021T431E-1 Service Manual page 129

2.4.1.7 Outdoor IGBT sensor is faulty
Check the connection
between temperature
sensor and PCB. Is it
properly wired?
Yes
Measure the resistance
value of the sensor. Is it
within acceptable
parameters?
Yes
Replace outdoor main PCB
2.4.1.8 Communication malfunction between indoor and outdoor units
The same as E1 in outdoor.
Electrical Control System
No
Ensure proper connection
No
Replace the sensor
Troubleshooting
127