General Functions
SiBE04-101
36
Main Function
1.15
Freeze up Prevention Function in Cooling
Outline
During Cooling/Dry operation, when the heat exchanger’s temperature falls down excessively, the capacity
supply will be reduced (frequency step down) so as to prevent freeze of the heat exchanger and the
creation of dew on a rotor caused by a excessive capacity supply to the indoor unit.
Details of the
Control
This air conditioner is equipped with a guard timer to retard the anti-freezing control for 6 to 10 min.
even when the heat exchange temperature has been lowered, in consideration of unstable condition
which may be seen after the operation is started or the thermostat starts to work.
When 6 to 10 min. elapses, anti-freezing control is conducted for each zone in accordance with the heat
exchange temperature.
∗
DTO : Freeze protection temperature of heat exchanger
The restriction for frequency is not conducted in the return area by means of freeze protection control.
Frequency is increased approximately every 2 Hz/min. in the up-area.
Frequency alteration in the steady area is not conducted.
Frequency - down is carried out in the step down area approximately every 2 ~ 4 Hz/min..
Compressors stop in the stop area. After compressor stops, fan keeps operating in 700 rpm for H type
and 800 rpm for J type (LL operation), aiming at rising heat exchanger’s temperature.
Setting a constant
50 Class
60 Class
70 Class
DTO4
13˚C
DTO3
6˚C
DTO2
5˚C
DTO1
3˚C
DTO0
0˚C
Return
at the descent of
heat exchanger temp.
at the ascent of heat exchanger temp.
Return from stop.
DTO0
DTO1
DTO2
DTO3
DTO4
Step down area
Steady area
Stop area
Up-area
(R1228)
SiBE04-101.book Page 36 Monday, October 15, 2001 3:08 PM
