MXS Service Manual

SiUS121736EA Control Specification
Functions and Control 102
4.11 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 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°C (C°F))
Frequency
Compressor
Four way valve
Fan
ON
OFF
ON
OFF
ON
OFF
0 Hz 0 Hz
D Hz
E Hz
5 sec.
PI control
5 sec.
J sec.
(R21926)
F sec.
G sec.
H sec.
Electronic
expansion valve
opening
(operating room)
Electronic
expansion valve
opening (stop
room)
Normal
control
K pulse
zone
N pulse
zone
L pulse
zone
M pulse
zone
Starting
control
Normal
control
P pulse zone
Q pulse
zone
Starting
control