Defrost Control - Daikin FTXM-K Series Service Manual

SiBE041434E

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.
Detail Conditions for Starting Defrost
Conditions for Canceling Defrost
The judgment is made with the outdoor heat exchanger temperature. (B°C)
A (minutes)
B (°C)
C (Hz)
D (Hz)
E (seconds)
F (seconds)
G (seconds)
H (seconds)
J (pulse)
K (pulse)
L (pulse)
Function 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 (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.
Frequency
ON
Compressor
OFF
ON
Four way valve
OFF
ON
Fan
OFF
Electronic
expansion valve
Normal
opening
control
20/25/35 class
28
4 ~ 18
56
56
30
60
480
80
450
200 ~ 280
200
: The same value continues.
C Hz
0 Hz
F sec.
E sec. G sec.
5 ~ 8 sec.
J pulse K pulse zone
zone
42/50 class
20 ~ 25
6 ~ 30
64
72
40
210
450
90
400
350 ~ 400
400
Control Specification
D Hz
0 Hz
H sec.
5 ~ 8 sec.
Starting
L pulse
control
zone
PI control
(R21278)
46