SiUS041111
Control Specification
Function and Control
43
3.10 Defrost Control
Outline
Defrosting is carried out by the cooling cycle (reverse cycle). The defrosting time or outdoor heat
exchanger temperature must be more than a certain value to finish.
Detail
Conditions for Starting Defrost
The starting conditions are determined with the outdoor temperature and the outdoor heat
exchanger temperature.
The system is in heating operation.
The compressor operates for 6 minutes.
More than 28 minutes of accumulated time pass since the start of the operation, or ending the
previous defrosting. (09/12 class)
More than 15 ~ 25 minutes (depending on the duration of the previous defrost control) of
accumulated time have passed since the start of the operation, or ending the previous
defrosting. (15/18/24 class)
Conditions for Canceling Defrost
09/12 class
The judgment is made with outdoor heat exchanger temperature. (4 ~ 22°C, 39.2 ~ 71.6°F)
Frequency
Compressor
Four way valve
Fan
ON
OFF
ON
OFF
ON
OFF
0 Hz
72 Hz
84 Hz
90 Hz
5 sec.
380 pulse
360 pulse
450 pulse
450 pulse
Initial opening
PI control
5 sec.
40 sec.
40 sec.
630 sec.
60 sec.
(R14666)
Electronic expansion
valve opening
