Lennox LI018CI-180P432 Service Manual page 52

Service Manual
3.Diagnosis for anti-high temperature, overload protection (AP1 below is control board of outdoor unit)
Main detection point:
● If the outdoor ambient temperature is in normal range;
● If the indoor and outdoor fan is running normal;
● If the radiating environment of indoor and outdoor unit is well.
Malfunction diagnosis process:
Installation and Maintenance
Anti-high temperature,
overload protection
If the outdoor ambient temperature is
higher than 127.4 °F?
N
After the unit de-
energized for 20min
If the radiating of outdoor
and indoor unit is well?
N
If the indoor and outdoor
fan work well?
Y
Replace
control board
AP1
End
Normal protection, please use
Y
it after improve the outdoor
ambient temperature
Improve the
radiating
Y
environment of
unit
1. Check if fan terminal
OFAN is connected well
N 2. Test if resistance value
of any two terminals is less
than 1k with ohmic meter
Replace fan
capacitor C1
Replace
outdoor fan
49