Midea MCD-18HRFN1-QRC4 Service Manual page 109

1.3.3.4 Defrosting mode：
For 12K units：
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.
Defrosting action：
on
Compressor
off
on
4-way valve
off
on
Outdoor fan
off
on
Indoor fan
off
Indoor fan breeze(10s)
xx=90
Electrical Control System
Frequency F3 FrequencyF16
10s
xx
10s
no longer than 10m
Electrical Control Function
30s
115