Fujitsu ASUH18LMAS Service Manual page 171

8-6. Low outdoor temperature protection
→hen the outdoor temperature sensor detects lower than the trigger condition below, the compres-
sor is stopped.
Operation mode
Trigger condition
Release condition
8-7. High temperature and high pressure release control
The compressor is controlled as follows.
• Cooling mode
Indoor unit heat exchanger
temperature rises
AB
BC
Zone C
Zone
Zone A Compressor is stopped.
Zone B The compressor frequency is decreased.
Zone C
The protection is released and the operation is returned to normal mode.
Zone D
• Heating mode
Indoor unit heat exchanger
temperature rises
AB
BC
CD
Zone D
Zone
Zone A Compressor is stopped.
Zone B
The compressor frequency is decreased.
Zone C
Zone D
The protection is released and the operation is returned to normal mode.
Zone E
8-6. Low outdoor temperature protection
Indoor unit heat exchanger
temperature drops
Zone A
Zone B
Stable zone
CD
Zone D
Indoor unit heat exchanger
temperature drops
Zone A
Zone B
Zone C
Stable zone
DE
Zone E
- (04-33) -
Cooling/Dry
-4°F (-20°C)
5°F (-15°C)
AB: 149.0°F (65°C)
BC: 143.6°F (62°C)
CD: 140.0°F (60°C)
Operation
AB: 145.4°F (63°C)
BC: 131.0°F (55°C)
CD: 127.4°F (53°C)
DE: 122.0°F (50°C)
Operation
-7 rps/120 sec.
-15 rps/120 sec.
-2 rps/120 sec.
8. Various protections