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[5-2 Outdoor Unit Control ]
5-2-7
Defrost Operation Control
(1) Starting the defrost operation
The defrost cycle will start when all of the following three conditions are met: outside temperature, cumulative compressor
operation time, and evaporating temperature under <Condition 1>, <Condition 2>, or <Condition 3> are met.
Outside temperature
(TH7)
Cumulative compressor
operation time
Evaporating tempera-
ture (Te)
1) Evaporating temperature (Te)
SW4 (915) OFF
SW4 (915) ON
2) <Condition 1> and <Condition 2> Cumulative compressor operation time in the Heating mode
Function setting
SW4 (916) OFF
ON
3) <Condition 3> Cumulative compressor operation time in the Heating mode
Function setting
SW4 (916) OFF
ON
The defrost cycle will not start if other outdoor units are in the defrost cycle or until a minimum of 10 minutes have passed
since the completion of the last defrost cycle.
If 10 minutes have passed since compressor startup or since the completion of a defrost cycle, a forced defrost cycle can be
started by setting DIP SW4(913) to ON.
Under <Condition 1> or <Condition 2>, even when the defrost-prohibit timer is set to 90 minutes, the actual defrost-prohibit
time for the next defrost cycle will be 50 minutes if the last defrost cycle took 12 minutes or 15 minutes (when SW4 (916) and
SW4 (918) are set to ON).
Under <Condition 3>, even when the defrost-prohibit timer is set to 250 minutes, the actual defrost-prohibit time for the next
defrost cycle will be 150 minutes if the last defrost cycle took 12 minutes or 15 minutes (when SW4 (916) and SW4 (918) are
set to ON).
Under <Condition 3>, even when the defrost-prohibit timer is set to 150 minutes, the actual defrost-prohibit time for the next
defrost cycle will be 50 minutes if the last defrost cycle took 12 minutes or 15 minutes (when SW4 (916) and SW4 (918) are
set to ON).
All units in the heating mode will simultaneously go into the defrost cycle in a system with multiple units. The units that are
not in operation may or may not go into the defrost cycle, depending on the cumulative operation time of their compressors.
BS_05_L
Condition 1
-5ºC [23ºF] or above
After the time shown in the table below has elapsed (Note 2) After the time shown in the ta-
The evaporating temperature
has stayed below the tempera-
ture in the table below (Note1)
for 3 minutes
HP200, 250
-11 ºC
-8 ºC
SW4 (918)
OFF
ON
50
90
50
40
250
150
Condition 2
-5ºC [23ºF] or below
(Te ≤ 1.1 × TH7 - 7.5) continued
for 3 minutes or [{1.5 + 0.02 x
(20+TH7)} > 63LS] continued
for 3 minutes
Condition 3
ble below has elapsed
(Note 3)
The evaporating temperature
has stayed below the tempera-
ture in the table below (Note1)
for 3 minutes
13
chapter 5 -
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