Vogt P118F/HE100, Service Manual

Page: 41 / 126

05TA Service Manual
HOW YOUR TUBE-ICE

MACHINE WORKS
7/19/2013
4-1
4. How Your Tube-Ice
®
Machine Works
Principle of Operation
For a detailed description of the functions of each control panel component,
see Section 6. Operation of the machine is controlled by “Clean/Off/Ice”, “Start” and “Stop”
switches located in the control panel of the freezing unit. Automatic operation can be controlled by
an optional ice bin thermostat which will automatically stop and start the ice maker by the level of
the ice in the storage bin (NOTE: See FIGURE 3-8, “Ice Bin Thermostat Location” for instructions
on installation of the control sensor of the ice bin thermostat(s)). The type ice produced (cylinder or
crushed) is determined by how the machine cutter is set-up (cylinder is standard, crushed or
automatic is optional). The control wiring is arranged so that the unit will stop only upon the
completion of a thawing period whether by action of the “Clean/Off/Ice” switch in the “Off”
position or the ice bin thermostat.
The “Clean/Off/Ice” switch must always be set in the “Ice” position during normal ice-making
operation. It is set in the “Clean” position only when the equipment is to be cleaned as outlined in
the “Cleaning Procedure” (Section 7) and instructions shown on the water tank cover.
If it should become necessary to instantly stop the machine, push the “Stop” button. To restart the
machine, push the “Start” button. The machine will restart in a harvest, to clear out any ice
remaining in the freezer, if stopped during a freeze period.
FIGURES 4-1 & 4-2 illustrate the piping diagram of the refrigerant and water circuits of the Tube-
Ice
®
machine with numbers for easy reference. Throughout this manual, the numbers you see in
parentheses refer to the numbers in this piping schematic.
The freezer (2) is a shell and tube-type vessel. During the freezing period, water is constantly
recirculated through the vertical tubes of the freezer by a centrifugal pump (6). Make-up water is
maintained by a float valve (12) in the water tank (7). The liquid feed solenoid valve (20),
sometimes referred to as the “A” valve, is open and the thawing gas solenoid valve (18), sometimes
referred to as the “D” valve, is closed.
Refrigerant gas from the top of the freezer (2) passes through the suction accumulator (88), the heat
exchanger (13), and to the compressor (3). Here the cool gas is compressed to a high temperature,
high pressure gas which discharges through the oil separator (14) and into the condenser (15). In the
condenser, heat is removed and the gas is condensed to a high temperature, high-pressure liquid.
The high-pressure liquid goes through the accumulator boil out coil (88) and suction line heat
exchanger (13) where it gives up heat to the suction gas for compressor protection. In addition, this
liquid is subcooled and carried to the receiver (15R). Liquid refrigerant from the receiver flows
through the filter/drier (46), thawing chamber (16), liquid feed solenoid valve (“A” valve) (20) and
hand expansion valve (17) into the freezer. The float switch (22) is wired to the “A” solenoid valve
(20). The float switch energizes and de-energizes the “A” solenoid in response to the level of
refrigerant in the freezer. The cold liquid refrigerant enters the freezer where it absorbs heat from
the circulating water. Cool gas is pulled out of the freezer at the suction outlet thereby completing
the cycle.
The freezing period is completed by action of the freezer pressure switch in the control panel. The
water pump (6) is stopped and solenoid valve “A” (20) is closed. The thawing period then begins.
Solenoid valve “D” (18) is opened, the cutter motor (5M) is started and the harvest (thaw) timer is
activated. Warm gas from the receiver is discharged into the freezer through valve (18), thereby
slightly thawing the outer edge of the ice, which drops on the rotating cutter for sizing. See “Freezer
Period and Harvest Period” for more detailed description of operation.