Manitowoc Q130 series, Technician'S Handbook

Page: 142 / 236

142 Part Number 8001119 10/19
5. Install thermometer thermocouples on Suction
and Discharge line:
• Digital thermometers with remote
thermocouples must be used to obtain
temperatures
• Suction and Discharge line thermocouples
must be within 3" (76.2 mm) of the compressor
• Thermocouples must be insulated
• Doors and all panels must be in place
• Initial freeze cycle is not used for diagnostics.
Start monitoring temperatures 3 minutes into
the second freeze cycle.
6. Compare Suction and Discharge temperatures to
“QM45 Operating Temperatures” on page 207.
The charts list Normal suction and discharge
temperatures.
Analysis
Discharge
Line Temp
Suction
Line
Temp
Ice Fill
Pattern
Refer to
Diagnostics
for:
Normal Normal
Less fill on the
left side of the
evaporator
This is normal
operation
Low (20°F
[-7°C] or
more)
Low
(20°F
[-7°C] or
more)
Less fill on the
left side of the
evaporator
Expansion
Valve
Flooding
Normal or
High
High
(10°F
[-12°C] or
more)
Less fill on the
left side and
top 2 rows of
the
evaporator
Low on
Refrigerant/
Expansion
Valve Starving
Normal
Low (5°F
[-15°C] or
less)
Less fill on the
left side of the
evaporator
Refrigerant
Overcharge