Defrost Control - Daikin 4MXS-R Series Service Manual

SiUS121736EA

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
Conditions for Canceling Defrost
The judgment is made with the outdoor heat exchanger temperature. (B°C (C°F))
Functions and Control
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.
Frequency
ON
Compressor
OFF
ON
Four way valve
OFF
ON
Fan
OFF
Electronic
expansion valve
Normal
opening
control
(operating room)
Electronic
expansion valve
Normal
opening (stop
control
room)
E Hz
D Hz
0 Hz
G sec.
F sec. H sec.
5 sec.
K pulse L pulse M pulse
zone zone zone
P pulse zone
Control Specification
PI control
0 Hz
J sec.
5 sec.
Starting
N pulse
zone control
Q pulse Starting
zone control
(R21926)
102