Indoor Unit Fan Motor Over Temperature Protection; Compressor Temperature Protection (For 12/18 Model); Low Outdoor Temperature Protection - Fujitsu ACUH09LUAS1 Service Manual

8-4. Indoor unit fan motor over temperature protection

→hen satisfy the following conditions, the protection works.
• After the 90 seconds from the fan operation, detect less than 300 rpm for 10 seconds.
• IPM trip protection works.
• Current overload protection works.
→hen detecting the above condtion, recheck the condition after 6 minutes. →hen count the twice,
the protection works.
• Protection contents
Reduce the static pressure 20 Pa. →hen it does not dissolve even the minimum static pressure
condition, work the following operation.
– Fan motor error displayed when less than 300 rpm for 10 seconds is detected after the 90 sec-
onds from the fan operation.
– Fan stop 40 seconds when IPM trip protection works.
– Fan stop 50 seconds when corrent overload protection works.

8-5. Compressor temperature protection (for 12/18 model)

→hen the compressor temperature sensor detects higher than the trigger condition below, the com-
pressor is stopped. →hen the compressor temperature sensor detects the release condition, the pro-
tection is released.
Trigger condition
Release condition

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
8-4. Indoor unit fan motor over temperature protection
(3 minutes after compressor stop)
- (04-34) -
226.4°F (108°C)
176.0°F (80°C)
Cooling/Dry
5°F (-15°C)
14°F (-10°C)
8. Various protections