2. protective functions, Overload prevention during heating, Freeze prevention – Sanyo KHS2472 User Manual
Page 40
Overload prevention during heating
During HEAT operation, the temperature of the indoor heat
exchanger is used to control the frequency and lessen the load
on the compressor before the protective device is activated.
Cold-air prevention during heating
Compressor discharge temperature control
During heating, the fan speed is set to "LL" (very low) or stopped.
As the temperature of the indoor heat exchanger rises, the fan
speed is changed to the set speed.
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 Point A has been exceeded, the operation frequency is
reduced by a certain proportion.
c.
Area: Frequency increase is prohibited.
d.
At Point B and below, overload prevention is ended and
control is the same as in the
a
area.
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.
Approx.
127
(53)
At stability of operation
At start of operation
A
High
LL
Stopped
A
*
B
C
B
Indoor heat exchanger
A. Control start
B. Control end
Set fan speed
77
(25)
86
(30)
Approx. 104
(40)
a
b
c
d
a
b
c
d
Indoor heat exchanger
temperature °F(°C)
Indoor heat exchanger
temperature
°F
(
°C
)
Indoor heat exchanger
temperature °F(°C)
Approx.
117
(47)
36
(2)
43
(6)
46
(8)
•
The fan speed is forcibly changed to "LL" beginning 30 seconds
after the thermostat turns OFF.
•
At stability of operation refers to operation when the room
temperature has approached the set temperature.
•
When HEAT operation starts, the indoor fan is stopped until the
temperature of the indoor heat exchanger reaches 68°F(20°C)
or higher, or until the room temperature reaches 59°F(15°C) or
higher.
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
a
b
c
d
Compressor discharge temperature
°F
(
°C
)
Approx.
201
(94)
NOTE
8-2. Protective Functions
40