Fujitsu AS*G24LFCA Service Instruction page 50

For AOTG34LFT
Trouble shooting 23
OUTDOOR UNIT Error Method:
Low Pressure Error
Detective Actuators:
Suction pressure sensor
Outdoor unit Main PCB
Forecast of Cause :
1. 3-way valve not opened
3. Outdoor unit fan operation defective, foreign matter at heat exchanger
4. EEV defective, strainer clogged
6. Low pressure sensor characteristics defective
8. Main PCB failure
<Cooling operation>
Check Point 1 : Check if 3-way valve(gas side) is open.
If the 3-way valve(gas side) was closed, open the
3-way valve(gas side) and check operation.
OK
Check Point 2 : Check the EEV, strainer clogging
EEV operation check
Strainer not clogged?
Refer to PARTS INFORMATION 3
OK
Check Point 5 : Check the suction pressure sensor
Suction pressure sensor characteristics check
* For the characteristics of the suction pressure sensor.
(Refer to PARTS INFORMATION 8)
OK
Check Point 6 : Check the refrigerant amount
Leak check
OK
Check Point 7 : Replace Main PCB
If Check Point 1- 6 do not improve the symptom, replace Main PCB.
Indicate or Display:
Refer to error code table.
Detective details:
"Protection stop by suction pressure
repeats 5 times within 2 hours.
<Heating operation>
Check Point 1 : Check if 3-way valve(liquid side) is open.
If the 3-way valve(liquid side) was closed, open the
3-way valve(liquid side) and check operation.
Check Point 2 : Check the outdoor unit ambient temperature
Outdoor ambient temperature lower than operating range?
Check Point 3 : Check the outdoor unit fan operation,
No foreign object in air passage?
Heat exchange fins clogged
Fan rotates?
Outdoor unit fan motor check
Check Point 4 : Check the EEV, strainer clogging
EEV operation check
Strainer not clogged?
(Refer to PARTS INFORMATION 3)
02-25
0.02MPaG continued for 5 minutes
2. Outdoor unit ambient temperature too low
5. Solenoid valve defective
7. Insufficient refrigerant
OK
OK
heat exchanger
OK