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(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 unit fan
4)
A f t e r s a t i s f y i n g a l l a b o v e c o n d i t i o n s , i f
temperatures of the outdoor unit heat exchanger
temperature thermistor (Tho-R1, R2) and the
outdoor air temperature thermistor (Tho-A)
become lower than the defrost operation
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 start of compressor and the outdoor air
temperature is as shown by the lower figure.
LPT detection
(ii)
Defrost conditions B
1)
When previous defrost ending condition is the time out of defrosting 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 unit fan
(b) Ending conditions
When any of the following conditions is satisfied, heating operation starts.
(i)
When it has elapsed 8 minutes and 20 seconds after the start of defrost operation.
(ii)
When the outdoor unit heat exchanger temperatures (Tho-R1, R2), whichever the lower, becomes 12°C or higher for
10 seconds continuously.
(c) Switching of defrost control with SW3-1
(i)
If SW3-1 on the outdoor unit control PCB is turned to ON, it becomes easier to enter the defrost operation. Use this
when installing a unit at snowing regions.
(ii)
Control contents
1)
It allows entering the defrost operation under the defrost condition A when the cumulative heating operation
time becomes 30 minutes. It is 37 minutes at SW3-1 OFF (Factory default).
2)
It allows entering the defrost operation under the defrost condition B when the cumulative heating operation
time becomes 25 minutes. It is 30 minutes at SW3-1 OFF (Factory default).
3)
It allows the defrost operation with the outdoor unit heat exchanger temperature (Tho-R) and suction pressure
saturation temperature (SST) being higher than normal.
LPT invalid
2
4
Outdoor air temp. (°C)
-
-25
-27
-30
-25
-20
-18
Model 71 ~ 250
-2
Model 71
-8
-5
-6
-10
-10
-15
-15
-20
-24
-20
-25
-30
-31
-25
-27
-35
-25
-20
-18
-30
-25
-20
-18
Model 100 ~ 250
Model 71
-8
-8
-10
-10
-15
-15
-20
-20
-24
-24
-25
-25
-30
-28.6
-31
-30
-25
-20
-18
-35
-25
-20
-18
Model 100 ~ 250
-8
-10
-15
-20
-24
-25
-28.6
-30
-18
-25
-20
183
-
'17 • PAC-T-257
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
Defrost operation start
temperature zone
Defrost operation start
temperature zone
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
Defrost operation start
temperature zone
Defrost operation start
temperature zone
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
Defrost operation start
temperature zone
-15
-10
-5
0
Outdoor air temp. (℃)［Tho-A］
5 6
10
5 6
10
5 6
10
5 6
10
5 6
10
5 6
10
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