Welbilt FB081TF, Service Manual

Page: 48 / 96

48 Part Number REV00 04/08/2020
Troubleshooting Section 5
ANALYZING SUCTION PRESSURE OR TEMPERATURE
NOTE: Analyze discharge pressure/temperature before
analyzing suction pressure/temperature. High or low
discharge pressure/temperature may be causing high
or low suction pressure/temperature. See “24-Hour Ice
Production/ Refrigerant Pressure Charts” on page 85 for
charts.
Suction Pressure/Temperature High Checklist
Problem Cause
Improper installation Refer to Installation procedures.
Discharge pressure Discharge pressure/temperature is too
high and is affecting suction pressure/
temperature.
Refer to “Discharge Pressure/
Temperature High Checklist.”
Improper refrigerant
charge Overcharged
Wrong type of refrigerant
Non condensible in system
Other Non-OEM components in system
TXV flooding (check bulb mounting and
insulation).
Defective compressor
Suction Pressure/Temperature Low Checklist
Problem Cause
Improper installation Refer to Installation procedures.
Discharge pressure/
temperature Discharge pressure/temperature is too
low and is affecting suction pressure/
temperature. Refer to “Discharge
Pressure/Temperature Low Checklist.”
Improper refrigerant
charge Undercharged.
Wrong type of refrigerant.
Other Non-Manitowoc components in system.
Restricted/plugged liquid line drier.
Restricted/plugged tubing in suction
side of refrigeration system.
Expansion valve starving.
No water or insufficient pressure.
Moisture in refrigeration system.
Dirty evaporator.
Defective fan cycle control.
NOTE: Do not limit your diagnosis to only the items listed in
the checklists.
Water System Checklist
A water-related problem often causes the same symptoms
as a refrigeration system component malfunction.
Water system problems must be identified and eliminated
prior to replacing refrigeration components.
Water area (evaporator) is dirty
• Clean as needed
Water inlet pressure not between 20 and 80 psig
(1-5 Bar, 138-552 kPa).
• Install water regulator or increase water pressure
Incoming water temperature is not between 40°F (4°C)
and 90°F (32°C)
• If too hot, check the hot water line check valves in other
store equipment
Water filtration is plugged (if used)
• Install a new water filter
Water fill valve is stuck open or closed
• Clean/replace as needed
Water is leaking out of the float reservoir overflow tube
• Adjust or replace float