Carrier 42QZA009DS-1 Service Manual page 38

Auto fan action in heating mode:
8.4.4.3 High evaporator coil temp.T2 protection:
If T2>63℃, the indoor unit has no capacity demand and resume till 48℃.
8.4.4.4 Prevent Over-Heating
In heating mode, when the indoor unit has no capacity requirement due to indoor room temperature
increased, the Indoor fan will run in super breeze. (Anti-cold wind function has the priority)
8.4.4.5 Defrosting mode：
Condition of defrosting:
AC will enter the defrosting mode according to the value of temp. of T3 and the value range of temp. change
of T3 and also the compressor running time.
Condition of ending defrosting:
If any one of the following items is satisfied, the defrosting will finish and the machine will turn to normal
heating mode.
----T3 rises to be higher than TCDE1℃.
----T3 keeps to be higher than TCDE2℃ for 80 seconds.
----The machine has run for 10 minutes in defrosting mode.
Defrosting action：
T1-Td
35
L
(H+-L)*0.2+L
(H+-L)*0.4+L
(H+-L)*0.6+L
(H+-L)*0.6+L
(H+-L)*0.8+L
H+