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5. Defrost operation control
(1) Starting the defrost operation
• Defrost operation is started when the pipe temperature (TH5) of -10˚C or below (-8˚C or below for P400-
type and above) has continuously been detected for 3 minutes after the integrated compressor operation
time of 50 minutes have passed.
• If 10 minutes have passed since compressor start-up or since the completion of defrost operation, forced
defrost operation will start by turning on the forced defrost switch (DIPSW2-7).
• Even if the defrost prohibit timer is set to 90 minutes, the actual defrost prohibit time for the next operation
will be 50 minutes if defrosting took 15 minutes.
(2) Defrost operation
(3) Completion of defrost operation
• Defrost operation will stop when 12 minutes have past since the beginning of defrost operation (15 minutes
when the defrost prohibit timer is set to 90 minutes), or when the piping temperature (TH5) of 10˚C or above
has been continuously detected for 2 minutes. (TH5 above 7˚C for 2 minitues for P400 models and above)
• Defrost operation will not stop its operation for 2 minutes once started unless the piping temperature
exceeds 25˚C within 2 minutes, in which case the operation will stop.
(Above 20˚C within 2 minitues for P400 type models and above)
(4) Problems during defrost operation
• If a problem is detected during defrost operation, the operation will be stopped, and the defrost prohibition
time based on the integrated compressor operation time will be set to 20 minutes.
(5) Change in the number of operating indoor units during defrost operation
• Even when there is a change in the number of operating indoor units during defrost operation, the operation
will continue, and an adjustment will be made after the completion of the defrost operation.
• Defrost operation will be continued, even if the indoor units stop or if thermo is turned off, until it has run its
course.
Compressor frequency
Outdoor unit fan
Stopped
SV1
ON
SV3 (P450-P650 types only)
ON
21S4a
OFF
21S4b
OFF
21S4c (P400-P650 types only)
OFF
SV5b
OFF
SV5c (P400-P650 types only)
OFF
LEV1
480 pulses
Model
No.1 Compressor
No. 2 Compressor
P200 type
72
–
P250 type
53
–
P300 type
65
–
P350 type
65
–
P400 type
114
–
P450 type (50/60Hz)
110/100
ON (50/60Hz)
P500 type (50/60Hz)
110/100
ON (50/60Hz)
P550 type (50/60Hz)
110/100
ON (50/60Hz)
P600 type (50/60Hz)
110/100
ON (50/60Hz)
P650 type (50/60Hz)
110/100
ON (50/60Hz)