Airwell VVFA Series Service Manual page 42

4. Defrosting control
In order to have the effect heating operation, need defrosting control.
4.1 Entering condition:
• &
4.2 Defrosting control
During defrosting, four-way valve power off, outdoor fan stop, indoor fan stop, outdoor PMV open to 470pls.
4.3 Quit defrosting
• OR
• OR
• OR
5. Oil return control
5.1 Entering condition:
A: In cooling mode
The master unit compressor cumulative
• &
operation time
• OR
Note:
load rate=∑indoor HP(Thermo ON) / ∑indoor HP*100%
Ta≤20°C
After heating startup 60min
• OR
Last defrosting~ heating cumulative operation time is more than 60 minutes
A: Ta≥6°C, Te≤-10°C For 5min continuously
• OR
B: -15≤Ta<6°C, Te≤(5Ta-72)/7 For 5min continuously
C: -23≤Ta<-15°C, Te≤(Ta-69)/4 For 5min continuously
D: Tao<-23°C, Te≤-23°C For 5min continuously
X: During the oil return operation meets the following condition, the
cumulative operation time reset
• After defrosting operation 10min
• Outdoor Te≥15°C, for 1min continuously
• Outdoor Te≥20°C, for 30s continuously
• Outdoor Te≥30°C, for 5s continuously
• Tc ≥ 54°C
Load rate≤30%
• &
After the outdoor unit startup
Load rate ＞ 30%
• &
Finish the outdoor startup control~ after 20min
Outdoor Te≥10°C, for 1min continuously
OR
Outdoor Te≥15°C, for 10min continuously
When load rate<20%: after 2 hours
• OR
When load rate≥20%: after 4 hours
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