Carrier 42QHF009DS Service Manual page 52

(3) Indoor evaporator high-temperature protection in heating mode
For A5 duct, A3
four-way cassette (compact):
T2>63℃, the compressor will stop and restart when T2<48℃.
For the other types
T2>60℃, the compressor will stop and restart when T2<48℃.
11.7.4.4 High evaporator coil temp.T2 protection:
If T2>63℃, the indoor unit has no capacity demand and resume till 48℃.
Prevent Over-Heating(except for old four-way cassette (compact))
11.7.4.5
For console, A5 Duct and A3
requirement due to indoor room temperature increased, the Indoor fan will run in breeze. (Anti-cold wind function
has the priority)
For A2 four-way cassette (compact): In heating mode, when the indoor unit has no capacity requirement due to
indoor room temperature increased, if outdoor fan and compressor stop, the Indoor fan will run in setting fan speed,
otherwise, the Indoor fan will run in low. (Anti-cold wind function has the priority)
11.7.4.6 Defrosting mode：
Condition of defrosting:
If any one of the following items is satisfied, AC will enter the defrosting mode.
After the compressor starts up and keeps running, mark the minimum value of T3 from the 10th minutes to
15th minutes as T30.
1)If the compressor cumulate running time is up to 29 minutes and T3< TCDI1, T3＋T30SUBT3ONE≦T30.
2)If the compressor cumulate running time is up to 35 minutes and T3< TCDI2, T3＋T30SUBT3TWO≦T30.
3)If the compressor cumulate running time is up to 29 minutes and T3< TCDI3 for 3 minutes.
4)If the compressor cumulate running time is up to 120 minutes and T3<-15℃.
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.
T1-Ts
3
2
1
:
four-way cassette (compact)
Low
Medium
High
: In heating mode, when the indoor unit has no capacity
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