Service Manual

Control Specification SiUS041829E
54 Part 4 Functions and Control
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 defrosting.
Details 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 A 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.
Conditions for Canceling Defrost
The judgment is made with the outdoor heat exchanger temperature (B).
09/12 class 18 class
A (minute) 20 ~ 25 44
B (°C) 2 ~ 20 6 ~ 12
(°F) 35.6 ~ 68.0 42.8 ~ 53.6
C (Hz) 64 48
D (Hz) 64 70
E (seconds) 40 60
F (seconds) 60 60
G (seconds) 120 ~ 630 120 ~ 460
H (seconds) 50 60
J (seconds) 8 5
K (pulse) 400 450
L (pulse) 300 300 ~ 450
M (pulse) 350 300
Frequency
Compressor
Four way valve
Fan
ON
OFF
ON
OFF
ON
OFF
0 Hz 0 Hz
C Hz
D Hz
J sec.
PI control
8 sec.
H sec.
(R21661)
E sec.
F sec.
G sec.
L pulse zone
Electronic
expansion valve
opening
Normal
control
K pulse
zone
M pulse
zone
Starting
control