Mitsubishi Electric PURY-M200YNW-A1 Service Handbook page 159

[5-3 HBC Control ]
(2) 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.
Outside temperature
(TH7)
Cumulative compressor
operation time
Pipe temperature
(TH6)
1) Outdoor unit pipe temperature (TH6)
SW3-3 OFF
SW3-3 ON
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 SW002-7 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.
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- chapter 5
Condition 1
-5ºC [23ºF] or above
50 minutes or more
90 minutes or more if the defrost prohibit timer is set to 90.
The pipe temperature has
stayed below the temperatures
in the table below (Note1) for
three minutes.
-8ºC
-5ºC
Condition 2
-5ºC [23ºF] or below
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.
Condition 3
250 minutes or more
The pipe temperature has
stayed below the temperatures
in the table below (Note1) for
three minutes
BS_05_M