Operating Systems; Refrigeration System; Water System - Sub-Zero UC-15I Service Manual

Model UC-15I (Undercounter Ice Machine)

OPERATING SYSTEMS

There are three operating systems in the ice machine:

• Refrigeration System

• Water System

• Electrical (Electronic Control) System
Refrigeration System
The following components have been listed in the order
of refrigerant flow, with an explanation of their function
as part of the refrigeration system. (See Figure 3-2)
• Compressor: The compressor creates a high side
and low side pressure difference in the refrigeration
system by compressing the refrigerant gas, thus rais-
ing the pressure and temperature. During the ice
making cycle the compressor pushes this high-pres-
sure/high-heat gas to the condenser.
• Condenser: The high-pressure/high-heat gas travels
through the condenser, where the heat is dissipated
by cooler air being drawn over the condenser tubing
by the condenser fan. This changes the gas into a
high-pressure/warm liquid that then enters the filter-
drier.
• Filter-Drier: The high-pressure/warm liquid travels
through the filter-drier, which removes moisture from
the refrigerant before it enters the capillary tube.
Accumulator
Suction Line
Compressor
Figure 3-2. Refrigeration System (During Ice Making Cycle)
Filter Drier
Capillary Tube
• Capillary Tube: The warm liquid refrigerant travels
through the skinny capillary tube which is attached to
the suction tube and wrapped around the base of the
accumulator. As the warm liquid refrigerant travels
through the capillary tube it gives up heat to the cool
vapor refrigerant in the accumulator and to the cool
refrigerant gas traveling through the suction line. As
the refrigerant in the capillary tube gives up heat, the
pressure drops, so it is a low-pressure/cool liquid
before it enters the evaporator.
• Evaporator: A dramatic pressure drop occurs as the
low-pressure/cool liquid refrigerant leaves the small
diameter capillary tube and enters the larger diameter
evaporator tubing, and the refrigerant begins to
vaporize. This vapor travels through the evaporator
absorbing heat from the water being sprayed on the
evaporator. This cool vapor then enters the accumu-
lator.
• Accumulator: Another pressure drop occurs as the
cool vaporized refrigerant leaves the evaporator tub-
ing and enters the larger diameter accumulator tub-
ing. Any liquid or vaporized refrigerant that may
remain at this point is converted to gas. The capillary
tube is wrapped around the accumulator base to give
up heat to the refrigerant in the accumulator before it
enters the suction line.
Evaporator
Hot Gas Valve
Condenser
3-3
Theory of Operation
• Suction Line: The cool gas trav-
els through the suction line,
absorbing heat from the warm liq-
uid refrigerant traveling through
the capillary tube. This assures
that it is a luke warm gas before
it enters the compressor, where
the process begins again.
NOTE: There is an additional com-
ponent in the ice machine refrigera-
tion system which is used during
the harvest cycle, this component is
called the hot gas solenoid valve.
Its function is described below:
• Hot Gas Valve: During a harvest
cycle, the hot gas solenoid valve
interrupts the flow of high-pres-
sure / high-heat gas from the
compressor, diverting it past the
condenser, filter-drier and capil-
lary tube, directly to the evapora-
tor. This high-pressure/high-heat
gas warms the evaporator so that
the ice cubes release from the
cube molds.
#7012423 - Revision A - August, 2009