Thermo Scientific XBF40-MD Series Installation, Operation And Service Manual page 39

Table 2: Troubleshooting Procedures
SYMPTOM
Unit runs but little or no
refrigeration.
Run times are getting longer.
Displayed temperature does not
match freezer temperature.
Thermo Scientific XBF40-MD Series Blast Freezers
POSSIBLE CAUSE
1. Loss of refrigerant.
2. Compressor will not pump.
3. Inoperative condenser fan.
4. Dirty insufficient air flow
5. High room temperature.
6. Refrigerant leak.
7. Condenser fan blade is loose.
8. Excessive ice on or in evaporator
9. Improper TXV settings
1. Needs calibration.
2. Defective sensor.
TEST AND CORRECTION
1. Check for the leak, repair, evacuate
and recharge.
2. Install low-side gauge. If running
pressure is no lower than starting
pressure, replace
evacuate and recharge.
3. Check for fan blade obstruction.
Replace fan motor if necessary.
4. Remove/Clean
ensure cabinet has a minimum of 6'
clearance all around it. Check for
fan blade obstruction. Replace fan
motor if defective.
5. Ensure room temperature is
< 32.2°C (90°F).
6. See Leak Check and Charging
procedures.
7. Tighten fan blade.
8. Check defrosts settings on the
controller. Defrosting required of
the evaporator.
9. Contact Service Support
1. Recalibrate per specified procedure.
2. Replace Sensor
Installation, Operation and Service Manual
Appendix
compressor,
condenser filter;
35