
159 of 222 pages
Operating and service manual
870
PTI defrost
Alarm
Description
PTI Defrost Fault
Cause
Trouble
shooting
Possible causes:
•
Defect Tevap temperature sensor.
•
Defect Psuc pressure sensor.
•
Defect heaters.
•
Defect hot gas valve.
•
Evaporator was filled with too much ice.
Accompanied alarms:
•
N/A.
Trouble shooting:
1) Defrosting is terminated when Tevap rises above +15°C (+59°F). Check
Tevap and Psuc sensors according to trouble shooting in alarms AL 123 and
AL 207.
2) The heaters may be defect. Start the heaters in manual mode and see if the
current consumption is higher than 5 A per phase else the heaters or the
power cables for the heaters may be defect.
3) The hot gas valve is not working properly and the heaters may be defective.
Check trouble shooting for the hot gas valve in alarm AL 844.
4) See if the evaporator is filled with ice (through the inspection holes).
Be
careful with the evaporators fans!
Criteria
Defrost terminated on 45 min. time-out
Controller
action
None
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 Tset
Tact
Tevap
Tret