York YHKJXH012BAM--FX Service Manual page 107

exchanger and make defrosting control.
3.5.1 Enter condition:
After the unit is in heating for 10 minutes and compressor run for 45 minutes in all , according
to check the defrosting temp. sensor Te and outdoor ambient temp. sensor Tao, if they can
meet the following condition, entering in defrosting operation.
1、 5℃（E）<Tao，Te<=-6℃（E） ；
2、 -6℃（E）<=Tao<=5℃，Te≤C×Tao－α；
Herein ：α=8（E）;C：Tao＜0℃，C=0.8; Tao≥0℃，C=0.6
3.Tao<-6℃，Te≤-15℃（E）and defrosting compressor run for 48 minutes in all。
3.5.2 Cancel condition:
It will take max. 10minutew from beginning defrosting to quit it. Te sensor will measure the
condition of outdoor heat exchanger, if the temp. is over 10℃ for 60s or is up to 14℃ for 30s,
the defrosting will be over.
3.5.3 Defrosting operation flow chart:
inverter compressor
outdoor fan motor
4-way valve
Unload valve SV1
PMV auto open angle
Indoor fan motor
Beginning
60s
30s
indicated FQY
50HZ
10s
ON
OFF
ON
OFF
ON
OFF
ON
OFF
defrosting FQY 85 Hz （E）
32HZ
send signal to indoor unit
250pulse（E）
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End
60s
soft startup
auto
auto
auto open angle
anti-cold air function