Lennox LM009CI-100T432-1 Service Manual page 43

6. High temperature and overload protection (AP1 below means control board of outdoor unit) E8
Main detection points:
● If the outdoor ambient temperature is in normal range;
● If the indoor and outdoor fan are running normally;
● If the radiating environment of indoor and outdoor unit is good.
Malfunction diagnosis process:
Start
If the outdoor ambient temperature is
higher than 53°C?
No
If the airflow of indoor and outdoor unit
is good?
No
If the indoor and outdoor fan are
running normally?
Yes
Replace outdoor
mainboard
End
40
Normal protection, please use it
Yes
after improving the outdoor ambient
temperature
No
Improve the radiating environment of
unit (clean the heat exchanger and
remove surrounding obstacles)
No
Connect normally?
Yes
Fan capacitor is broken?
No
Motor is broken?
No
Replace mainboard
Service Manual
Unit restarts Yes
normally
Yes
Unit restarts
normally
Yes
Adjust the
connection
Replace fan
Yes
capacitor
Yes
Replace motor
Installation and Maintenance