– 30 –
8-15-2. Current Limit Control and High-tempera-
ture Limit Control (during Heating)
When the load increases (overload) or the line volt-
age drops during operation of the air conditioner, the
operating current increases, and when the power ca-
pacity is exceeded, the circuit breaker is activated.
This control is performed automatically when the cur-
rent (heat exchanger temperature) exceeds a certain
value so that it is decreased automatically to prevent
overload to the supply. Control is performed as de-
scribed in (1) and (2).
(1) Current limit control'
Control is performed as shown below by detect-
ing the compressor operation current with a cur-
rent sensor.
Fig. 8-28
(2) High-temperature limit control
Control is performed as shown in Fig. 8-29 by
detecting the heat exchanger temperature with a
heat exchanger sensor (TC).
Fig. 8-29
8-16. Cool Airflow Prevention Control
(1) When control is performed with a thermostat, and
the thermostat is set to off, the indoor fan stops
operating, and restarts at the ultra low speed af-
ter 2 minutes and 20 seconds.
Fig. 8-30
(2) When the heat operation starts, the indoor fan is
kept off until the indoor heat exchanger tempera-
ture reaches a set temperature.
Fig. 8-31
(3) As soon as the defrost operation starts, the in-
door fan stops.
When the value than I
2
point continues for 5 minutes
the compressor is tuned off.
When the value than I
3
point
continues for 3 seconds
the compressor is tuned off.
Outdoor fan operation
I
3
8.2
(A)
I
2
6.9
I
1
5.8
I
0
5.5
Compressor
Outdoor fan
ON
OFF
ON
ON
OFF
ON
Set temperature
-1
Indoor fan
ON
OFF
ON
Thermostat
ON
ON
ON(OFF)
Heat
exchanger
temperature
33
( C)
25
20
Fan ON
UL
UL
Fan OFF
(Control is performed
according to the air volume
changeover position.)
Fan stop
Heat
exchanger
temperature
60
53
52
Outdoor fan
Compressor
ON
ON
ON
ON
OFF
OFF
( C)
