Fujitsu ASU18RLF Service Instructions Manual page 76

Trouble shooting 31
OUTDOOR UNIT Error Method:
4-Way Valve Error
Detective Actuators:
Indoor unit main PCB
Heat Ex. temperature thermistor
Room temperature thermistor
4-Way valve
Forecast of Cause:
1. Connector connection failure
5. Main PCB failure
Test 1 : Check connection of Connector
Check if connector is removed.
Check erroneous connection.
Check if thermistor cable is open.
>> Upon correcting the removed connector or miss-wiring, reset the power.
OK
Test 2 : Check thermistor of Indoor unit
Isn't it fallen off the holder?
Is there a cable pinched?
>> Check characteristics of thermistor, (Refer to Trouble shooting 7,8),
If defective, replace the thermistor.
OK
Test 3 : Check the solenoid coil and 4-way valve
[ Solenoid coil ]
Remove CN202 from PCB and check the resistance value of coil.
Resistance value is about 2085 +10% (68°F(20°C))
>> If it is Open or abnormalresistance value, replace Solenoid Coil.
[ 4-way valve ]
Check each piping temperature,
and the location of the valve by the temperature difference.
>> If the value location is not proper, replace 4-way valve.
OK
Test 4 : Check the voltage of 4-way valve
Check the CN202 voltage of Main PCB
Check if AC187V(AC208V-10%) - 253V(AC230V+10%) appears at CN 202 of Main PCB.
[ Heating operation ]
>> If it is not voltage, Replace Main PCB. (SERVICE PARTS INFORMATION 10)
[ Cooling operation ]
>> If it is voltage, Replace Main PCB. (SERVICE PARTS INFORMATION 10)
OK OK
Test 5 : Replace Controller PCB
If Test 1- 4 do not improve the symptom, replace Controller PCB of Indoor unit .
Indicate of Display:
Indoor Unit
Operation lamp : 9 time Flash
Timer lamp
ERROR CODE : [E : 99]
Detective details:
When the indoor unit Heat Ex. temperatrure is compared with the
room temperature, and either following condition is detected
continuously 2 times, compressor stops.
・
Cooling operation
[Indoor Heat Ex. temperature] - [Room temperature] >
・ Heating operation
[Indoor Heat Ex. temperature] - [Room temperature] <
If the same operation is repeated 5 times.
the compressor stops permanently.
2. Thermistor failure
6. Controller PCB failure
-
02-36
Outdoor Unit
A
: 9 time Flash
9
: Light ON
3. Coil failure 4. 4-way valve failure
Monitor
B C D E F
9
: Light OFF n : n time blinking
20°F(10°C)
-20°F(-10°C)