Installation manual

[ VII Control ]
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HWE10050 GB
Defrost Operation 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 <Condition 1>, <Condition 2>, or <Condition 3> are met.
1) Pipe temperature(TH6)
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 SW2-7 to ON.
Even if the defrost-prohibit timer is set to 90 minutes (or 150 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. 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.
Condition 1 Condition 2 Condition 3
Outside temperature
(TH7)
-5ºC [23ºF] or above -5ºC [23ºF] or below
Cumulative compressor
operation time
50 minutes or more
90 minutes or more if the defrost prohibit timer is set to 90.
250 minutes or more
Pipe temperature
(TH6)
The pipe temperature has
stayed below the temperatures
in the table below (Note1) for
three minutes.
The pipe temperature (TH6)
has stayed at or below the val-
ue obtained from the formula
"Outside temperature (TH7) -
10ºC [18ºF]" for three minutes.
or the 63LS reading has stayed
below the value obtained from
the formula "1.5 + 0.02 x
(20+TH7)" for three minutes.
The pipe temperature has
stayed below the temperatures
in the table below (Note1) for
three minutes
P200 - P300, EP200 P350, P400, EP250, EP300 P450, EP350
SW3-3 OFF -10ºC -8ºC -8ºC
SW3-3 ON -5ºC -5ºC -5ºC