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[ VII Control ]
-7- Defrost Operation Control
(1) Starting the defrost operation
The defrost cycle will start when all of the three conditions (outside temperature, cumulative compressor operation time, and
pipe temperature) under , , or are met.
Outside temper-
ature (TH7)
Cumulative
compressor op-
eration time
The pipe temperature has stayed at or be-
low -10ºC for three minutes or the 63LS
reading has stayed below the value ob-
Pipe tempera-
tained from the formula "1.5 + 0.02 x TH7"
ture (TH3)
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 SW2-7 to ON.
Even if the defrost-prohibit timer is set to 90 minutes (or 250 minutes for "Condition 3" to be met), the actual defrost-prohibit
time for the next defrost cycle is 50 minutes if the last defrost cycle took 12 minutes.
All units in the heating mode will simultaneously go into the defrost cycle in a system with multiple units. Units that are not in
operation will remain stopped.
(2) Defrost operation
Outdoou unit
BC controller
HWE10020
Condition 1
-5ºC [23ºF] or above
90 minutes or more if the defrost prohibit timer is set to 90.
for three minutes.
Compressor frequency
Outdoor unit fan
SV1a
SV2
SV5b
21S4a
SV9
LEV1
LEV3
SVM1
SV B
SV A
Condition 2
50 minutes or more
The pipe temperature has stayed below the
value obtained from the formula "Outside
temperature (TH7) -5ºC" for three minutes,
or the 63LS reading has stayed below the
value obtained from the formula "1.5 + 0.02
x TH7" for three minutes.
Model
RP200 model
RP250 model
RP300 model
G type: 1000, GB type: 60 (full closed)
Ports that are connected to the indoor units in cooling Thermo-ON
Other ports : OFF
- 121 -
-5ºC [23ºF] or below
250 minutes or
The pipe tem-
Compressor frequency
120 Hz
103 Hz
103 Hz
Stopped
ON (open)
ON (open)
ON (open)
OFF
OFF (closed)
G type: 4000
ON
OFF
Condition 3
more
perature has
stayed at or
below -10ºC
for three min-
utes.
GB
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