Operating and service manual
146 of 222 pages
801
Controller
Alarm
Description
Controller Internal Voltage Reference Fault
Cause
Trouble
shooting
Possible causes:
• Power supply for controller PCB defect.
• Controller PCB defect.
Accompanied alarms:
• Check for AL 951 up to AL 996
• There may be other accompanied alarms.
Trouble shooting:
1) See trouble shooting for accompanied alarms. If none appears, then
proceed with 3).
2) Clear other active alarms with sensors.
3) The power supply or power-cable for controller PCB defect. Measure
voltage for the controller PCB.
a. If voltage is ok, the controller PCB is defect and controller door must be
replaced.
b. Measure voltage for all sensors. Should be between 4.80V DC and 5.20V
DC for temperature and pressure sensors. Humidity sensor must be
between 12.00V DC and 34.00V DC. If not ok, the sensor or cable is
defect. Replace sensor.
c. Measure outlet on transformer between T3 and T4. Correct range 15.30V
AC – 24.30V AC. Measure between T5 and T6. Correct range 18.86V AC
– 30.00V AC. If within range transformer is ok.
d. Replace controller door.
Criteria
One or more of the internal reference voltages are out of limits
Controller
action
FC will soon trip with AL 516 and stop compressor
Log
X
Alarm
X
Alarm light
Slow flash
Consequence
Test failed
Elimination
Alarm may then be deleted after test completed
Log data
Parm 1
Parm 2
Parm 3
Parm 4
Parm 5
Active/Inactive Step no.