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18.3 Defrost control
Defrosting control is required for effective heating operation.
• &
•
Tao≤20°C
• OR
Y: Tao≤-5°C, Te1 or Te2≤ -1°C, accumulate for 2 hours, and after the last defrosting
(including the initial power on) ~ Heating accumulated time exceeds 4 hours;
Tao
＞
-5°C
,
Te1 or Te2≤ -1°C, accumulate for 2 hours, and after the last defrosting
(including the initial power on) ~ Heating accumulated time exceeds 2 hours.
Note: When time for defrosting, if outdoor units Te1 & Te2≥ 10°C and last for 1 minute,
or outdoor units Te1 & Te2≥15°C and last for 10 seconds, then time reset. Before
heating start, Te1 & Te2≥ 10°C, the previous timing will be reset.
• OR
•
30 minutes after heating start, and Te1 or Te2≤ -1°C, the accumulated time
exceeds 30 minutes
•
The last defrosting~Heating and compressor operates, Te1 or Te2≤ -1°C, the
accumulated time exceeds 50 minutes
• &
• OR
•
A: Tao≥ 6°C, Te1 or Te2≤ -6°C and last for 5 minutes
•
B: -5°C≤Tao
＜
6°C, Te1 or Te2≤(5Tao-72)/7 and last for 5 minutes
• X: If oil return operation mey the following conditions, the
accumulated running time will be cleared
• OR
•
Outdoor units Te1 & Te2≥10°C and last for 1 minute
•
Outdoor units Te1 & Te2≥15°C and last for 4 seconds
•
N: Two-Twi<=TW* (hz/hz0), last for 5 minutes;
(Note: "hz" indicates the current frequency; hz0 indicates the hightest
frequency 20 or 25 minutes after the last time 4-way valve switch to
ON; TW indicates the corresponding value of (Ttwo-Twi)*0.5 at hZ0, the
range is (1-5)°C
•
C: -15°C≤Tao
＜
-5°C, Te1 or Te2≤(5Tao-72)/7 and last for 5 minutes
•
D: -23°C≤Tao
＜
-15°C, Te1 or Te2≤(Tao-77)/4 and last for 5 minutes
• E: Tao
＜
-23°C, Te1 or Te2≤(5Tao+15)/4 (minimum-30°C), and last
for 5 minutes
