Compressor discharge temperature control
Freeze prevention
During COOL or DRY operation, freezing is detected and
operation is stopped when the temperature of the indoor heat
exchanger matches the conditions below.
1.
Freeze-prevention operation is engaged when the
temperature of the indoor heat exchanger is below 43°F(6°C).
2.
Restart after freeze-prevention operation occurs when the
temperature of the indoor heat exchanger reaches 46°F(8°C)
or above.
a.
Area: Automatic capacity control
b.
When the temperature drops below Point A, the operation
frequency is reduced by a certain proportion.
c.
Area: Frequency increase is prohibited.
d.
When the temperature reaches Point C or above, freezing
prevention is ended and control is the same as in the
a
area.
* When the temperature drops to below 36°F(2°C)
(continuously for 2 minutes or longer), the compressor stops.
Once the freeze condition is detected, the air conditioner will
work less than the maximum frequency until it is turned off.
The Freeze Prevention Control during the Low Ambient Cooling
Mode (outside air temperature:59
°F(
15
°C)
or lower) is as follows.
The compressor stops when the temperature of indoor heat
exchanger becomes less than 36°F(2°C).
The compressor restarts when the temperature of indoor heat
exchanger becomes 46°F(8°C) or higher.
A
*
B
C
abcd
Indoor heat exchanger
temperature °F(°C)
36
(2)
43
(6)
46
(8)
This function controls the operation frequency to prevent the
compressor discharge temperature from rising more than a
specified temperature.
a.
Area: Automatic capacity control.
b.
When the temperature rises above Point A, the operation
frequency is reduced at a specified rate.
c.
Area: Further frequency increase is prohibited.
d.
When the temperature falls below Point B, prevention of a rise
in frequency is released and the air conditioner operates as in
a
area.
* The compressor will stop if the temperature of the compressor
discharge exceeds 248°F(120°C) due to shortage of gas or
other reason.
Approx.
214
(101)
A
B
abc d
Compressor discharge temperature °F(°C)
Approx.
201
(94)
NOTE
8-2. Protective Functions
This function prevents the circuit breaker or fuse from operating
to open the circuit. This function works when electrical current
has increased due to an increase in the cooling load,
or to a decrease in the power supply voltage. In these cases,
operation frequency is reduced or operation is interrupted auto-
matically to control the electrical current for operation.
When the cause of the increase in electrical current is rectified,
the system will resume operation in the original mode.
Cooling Dry
Peak current cut-off trips 22.5
Hz down 14.0
(A)
CT (Peak current cut-off control)
Cooling Dry
Peak current cut-off trips 17.5
Hz down 11.0
(A)
< CS-KS24NKU >
< CS-KS18NKU >
(CLxx models only)
46