Protective Functions - Sanyo SAP-KMV91G-S Technical & Service Manual

10-2. Protective Functions

10-2-1. Freeze Prevention
If the temperature of the indoor heat exchanger drops to the following level while the air conditioner is operating
in Cooling or Dry mode, it will detect a freeze condition and stop operation as long as necessary.
1. When the temperature of the indoor heat exchanger is less than 6°C, the air conditioner enters Freeze
Prevention mode.
2. Release of freeze prevention mode occurs when the temperature of the indoor heat exchanger is over 8°C.
8
A
6
2
(a)
If the temperature falls below 2°C (for more than 2 minutes) the compressor will stop operating.
NOTE
Once the freeze condition is detected, the air conditioner will work less than the maximum fre-
quency until it is turned off.
10-2-3. Compressor Discharge Temperature Control
This function controls the operating frequency to prevent the compressor discharge temperature from rising more
than the specified temperature.
Compressor discharge temperature
About
108¡C
About
86¡C
(a)
The compressor will stop if the temperature of the compressor discharge exceeds 120°C due to
NOTE
shortage of gas or other reason.
10-2-4. CT (Peak Current Cut-Off Control)
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 automatically 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 origi-
nal mode.
Operation at 230V
Peak current cut-off trips
Hz down Normal
C
B
(b) (c)
A
B
(b) (c) (d)
(A)
Cooling • Dry
22
Free 18.2
11A 11.0
8.5A 8.5
(a) Area — the air conditioner follows auto performance
control.
(b) When the temperature falls below point A, the oper-
ating frequency is reduced at a specified rate.
(c) Area — further frequency rise is not allowed.
(d) When the temperature rises above point C, freeze
prevention is released and the air conditioner oper-
(d)
ates as in (a).
(a) Area — the air conditioner follows auto performance
control.
(b) When the temperature rises above point A, the operat-
ing frequency is reduced at a specified rate.
(c) Area — further frequency rise is not allowed.
(d) When the temperature falls below point B, prevention of
a rise in frequency is released and the air conditioner
operates as in (a).
36