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Algorithm & Control
27
09 class
12 class
18 class
24 class
A (minute)
20 - 25
20 - 25
25
25
B
(°C)
2 - 20
2 - 20
6 - 30
6 - 30
(°F)
35.6 – 68.0
35.6 – 68.0
42.8 – 86.0
42.8 – 86.0
C (Hz)
64
64
48
48
D (Hz)
64
64
42
42
E (seconds)
40
40
60
60
F (seconds)
60
60
60
60
G (seconds)
630
630
490
490
H (seconds)
40
50
60
90
J (seconds)
8
8
5
5
K (pulse)
400
400
450
450
L (pulse)
300
300
300 – 450
300 – 450
M (pulse)
200
350
200
200
2.20 Indoor Coil Freeze Prevention
Only available in cooling mode.
When the indoor coil temperature < 2°C (35.6°F), the compressor starts to drop the frequency.
This protection will cut in when:
• Indoor coil temperature < 0°C (32°F) for more than 180s. Compressor will stop, outdoor fan stop after
30s and indoor fan can only run at lowest fan speed.
The unit can only be restarted after 3 minutes.
When the indoor coil temperature > 13°C (55.4°F), the compressor frequency will be reset based on the
outdoor ambient, room and set temperature.
2.21 High Pressure Protection
To prevent high pressure in the system.
Compressor operating frequency is adjusted based on upper limit of coil temperature.
Upper Limit Coil
Temperature
Compressor frequency
A
64°C / 147.2°F
B
C
The compressor frequency is adjusted based on coil temperature:
•
During cooling mode : outdoor coil temperature.
•
During heating mode : indoor coil temperature.
This protection is activated when the coil temperature > 64°C (147.2°F), the compressor stops and outdoor
fan stops after 30s.The unit can only be restarted after 3 minutes.