Carrier 619FB Service Manual page 29

3. High temperature and overload protection (E8) (AP1 below means control board of outdoor unit)
Main detection points:
S Is the outdoor ambient temperature in normal range?
S Is the indoor and outdoor fan running normally?
S Is the condensing unit blocked with dirt and debris?
E8 is displayed
If the outdoor
ambient temperature is higher
than 127°F?
Is the unit clear of debris
and the coil is clean?
No
Are the indoor and outdoor
fan running normally?
Yes
Replace outdoor
mainboard
End
Yes
No
Yes
Fig. 32 – Troubleshooting
Normal protection, unit starts
when ambient temperature
lowers.
No
Clean the heat exchanger
and remove surrounding obstacles
No
Are the connections
tight?
Yes
Fan capacitor is broken?
No
Motor is broken?
No
Replace mainboard
29
Unit restarts
Yes
normally
Unit restarts
Yes
normally
Adjust the
Yes
connection
Replace Fan
Yes
capacitor
Replace Motor
Yes