technical & service manual dc inverter multi-system air conditioner

Control/conditions
HEAT When defrost operation
begins, frost has formed
on the outdoor unit
(when the ambient air
temperature is low).
Non-stop defrost
Unit operation Explanation
Indoor fan : Stopped
Outdoor fan : Stopped
Compressor : 70 Hz
Solenoid valve (for hot gas bypass): ON
4-way valve : Remains ON
Operation lamp : Red and orange ON
alternately
Defrost release Indoor fan turns ON.
After 10 seconds, the solenoid valve
(for hot gas bypass) turns OFF.
STOP
[Clean defrost]
Defrost is performed
when the outdoor unit is
stopped, and the
temperature of the
outdoor unit coil is at or
below the L1 line.
(Refer to Fig. 1.)
Operation is restarted
within 4 hours (only when
AUTO mode is selected
with the remote
controller).
Operation starts after 4
hours or more have
passed.
Outdoor heat
exchanger temperature
L2
L1
(–20) 0
Fig. 1
When the cold air feel has disappeared,
the indoor fan starts and gradually increases
speed until it reaches the set speed.
All indicator lamps turn OFF. The indoor and
outdoor units stop.
Starts operating in the same operating mode
(HEAT) and with the same temperature
settings as before operation was stopped.
New operation begins based on the
temperature conditions at the time the
ON/OFF button is pressed.
Outdoor air
temperature
(– 6)
(– 7)
(– 16)
(– 25)
Temperature of releasing
Defrost operation time
Heat exchanger
temperature for
releasing defrosting
18
Defrost operation begins based on outdoor heat
exchanger temperature and outdoor air
temperature conditions.
Non-stop defrost (Refer to Fig. 1)
1. After HEAT operation begins, the temperature
of the outdoor heat exchanger is at or below the
L1 line for 48 minutes.
(If outdoor air temperature is less than –3 °C,
the time is 48 minutes)
2. After HEAT operation begins, the temperature
of the outdoor heat exchanger is at or below the
L2 line for 120 minutes.
The 4-way valve remains ON during defrost.
The outdoor fan stops and the solenoid
valve turns ON, allowing the refrigerant to
bypass the indoor unit.
The operating frequency during defrost is
70 Hz. (Frequency is lowered if the current
peak cut-off function is activated.)
The maximum length of a single defrost
operation is 12 minutes.
For the outdoor heat exchanger temperature
conditions for ending defrost, refer to Table 1.
Within 4 hours after operation was stopped, it is
assumed that there has been no significant
change in the indoor and outdoor temperatures,
and the previous conditions (HEAT) are stored.
Less than 2 minutes 2 minutes or more
No releasing 14 °C or higher (*1)
*1 The temperature for releasing of defrosting is (20 °C) or higher when the
outdoor air temperature is less than 0 °C.
Table 1