Flooding Expansion Valve; Starving Expansion Valve/Low Refrigerant Charge; Overcharged System - Manitowoc SM050 Technician's Handbook

FLOODING EXPANSION VALVE

A flooding expansion valve will have discharge and
suction line temperatures 20°F (-7°C) lower than
normal freeze cycle temperatures. Normal suction line
temperature and low discharge line temperature DO
NOT verify a flooding valve. Both discharge line
temperature and suction line temperature must be low
to verify a flooding expansion valve. Ice fill pattern is
thin on the left hand side of the evaporator.
STARVING EXPANSION VALVE/LOW
REFRIGERANT CHARGE
Confirm water float valve is set correctly. An
overflowing standpipe mimics these symptoms
exactly.
SYMPTOMS:
• Ice Fill Pattern
• Thin on top two rows of the evaporator
• Thin on entire left side of the evaporator
• Thick on the bottom of the evaporator
• Freeze time longer than normal
Diagnosis can be confirmed by adding 2 oz (56.7 g) of
refrigerant: if the Suction line temperature drops or the
ice fill pattern on the top two rows fills in, the ice
machine is low on refrigerant. Refer to charging
procedures for access valve installation procedure.

OVERCHARGED SYSTEM

Suction line temperature will be slightly low during
freeze cycle 5°F (-15°C). Discharge line temperature
is normal. Actual amperage readings will be higher
than nameplate rating.
Part Number 8001119 10/19
Important
143