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44
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'19 • PAC-SM-332
(5) Defrost operation
(a) Starting conditions
If all of the following defrost conditions A or
conditions B are satisfied, the defrost operation
starts.
(i) Defrost conditions A
1) Cumulative compressor operation time after
the end of defrost operation has elapsed 37
minutes, and the cumulative compressor
operation time after the start of heating
operation (remote control ON) has elapsed 30
minutes.
2) After 5 minutes from the compressor ON
3) After 5 minutes from the start of outdoor fan
4) After satisfying all above conditions, if
temperatures of the outdoor heat exchanger temperature sensor (Tho-R1, R2) and the outdoor air temperature
sensor (Tho-A) become lower than the defrost operation starting temperature as shown by the right figure for 15
seconds continuously, or the suction gas saturation temperature (SST) and the outdoor air temperature (Tho-A),
which are obtained from the value detected by the low pressure sensor (LPT) stay for 3 minutes within the range
below the defrost operation start temperature as shown by the right figure.However, it excludes for 10 minutes
after the startof compressor and the outdoor air temperature is as shown by the lower figure.
LPT detection
Outdoor air temperature (°C)
2
4
LPT invalid
(ii) Defrost conditions B
1) When previous defrost ending condition is the time out of defrost operation and it is in the heating operation after
the cumulative compressor operation time after the end of defrost operation has become 30 minutes.
2) After 5 minutes from the start of compressor
3) After 5 minutes from the start of outdoor fan
(b) Ending conditions
When any of the following conditions is satisfied, the heating operation starts.
(i) When it has elapsed 10 minutes and 20 seconds after the start of defrost operation.
(ii) When the outdoor heat exchanger temperatures (Tho-R1, R2), whichever the lower, becomes 12°C or higher for 10
seconds continuously.
Outdoor air temp
erature
(
℃
)
[
Tho-A
]
Suction saturation temp
erature
(
℃
)
[
SST
]
-20
-25
-27
-30
-15
-10
-6
-5
-35
-15
-18
-10
-5
0
5 6
10
-25
-20
Defrost operation start temperature (SW3-1 ON)
Defrost operation start temperature (Standard)
Defrost operation start
temperature zone
Model FDC71