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Models C708/C709/C716/C717
Systems, Controls and Operations
Refrigeration System - Hot Gas Treatment
The refrigeration system utilizes a main compressor
that provides for heating and cooling of both the
freezing cylinder and the hopper. An AXV expansion
valve is used on the freezing cylinder to provide
consistent product quality by maintaining the
evaporating temperature at -15°F (-26°C).
A thermal expansion valve (TXV) is used on the
hopper system for the Cool Phase. The TXV
provides the required control of refrigerant mass flow
to control refrigerant floodback to the compressor.
There is a provision for liquid refrigerant injection to
the compressor suction to control excessive
compressor discharge temperature during the Cool
Phase. The bulb is located on the discharge line
near the compressor to sense when the discharge
temperature approaches 250°F (121°C). Note: The
valve opens at 230°F (110°C).
There are two liquid line solenoid valves to provide
control over the refrigeration to the hopper and
freezing cylinder during the Cool Phase. Both liquid
line solenoids are closed during the Hot Gas Heat
Phase.
Two hot gas solenoid valves are used during the
Heat Phase to direct the compressor discharge gas
to the freezing cylinder and hopper, bypassing the
condenser, freezing cylinder AXV and the hopper
TXV.
When only the hopper is being cooled, a hot gas
bypass valve is used to divert refrigerant gas to the
suction line.
In order to maintain product temperature above
150°F (65.5°C) for 35 minutes during the Hold
Phase, the compressor will cycle on and off.
The main system condenser is a 3-row 5/16” tube
and raised lance fin condenser. The liquid line
receiver helps control the variable amount of free
refrigerant in the system. A filter dryer is provided.
There is a liquid line - suction line heat exchanger on
the main refrigeration system.
Note: This information applies to both sides on the
C716 and C717 - independent systems.
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