Carrier X4 7300 Operation & Service Manual page 153

00053 BOX TEMP OUT-OF-RANGE - CONTINUED
CORRECTIVE ACTIONS:
1. Check Compartment Doors
Inspect all compartment doors. Must be closed, and not allowing any air leakage.
2. Defrost Evaporator
Initiate manual defrost cycle. Must terminate automatically. Verify that all ice cleared from evaporator
coil.
3. Check for any Shutdown Alarm(s)
Check the Alarm List for any shutdown alarms. Alarm conditions must be corrected and the alarm
cleared to continue.
4. Check for Alarm 00018 (Low Refrigerant Pressure Alarm)
Check for Alarm 00018 LOW REFRIGERANT
the alarm cleared to continue.
5. Check Refrigerant Charge
Refer to Section 8.7.2. Charge must be correct.
6. Check System Pressures
Install manifold gauge set and check and compare compressor discharge & suction pressures with
those shown in Unit Data. Refer to
7. Check for Alarm 00056 (Low Evaporator Airflow)
Check for Alarm 00056 CHECK EVAPORATOR AIR
the alarm cleared to continue.
8. Perform Pretrip Check
Clear Active Alarm list, then run Pretrip & check for any new alarms. Any active alarms must be cor-
rected and cleared before proceeding.
9. Check for Low Delta-T
Read delta-t from Unit Data. In Cool, the delta-t must be greater than (cooling more than) -1°F (-
0.56°C). In Heat the delta-t must be greater than 0 (SAT must be higher than RAT).
PRESSURE. Alarm conditions must be corrected and
Section 8.9.12 for instruction on comparison.
FLOW. Alarm conditions must be corrected and
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