VOGT ICE 12A4171M12, Service Manual

Page: 41 / 100

MHG-LR Service Manual
HOW YOUR ICE MACHINE WORKS
1/6/2010
4-2
from constantly recirculating water during the freeze period. As the ice thickness increases, the
freezer suction pressure decreases. At a set time, the PLC initiates the harvest period.
Dry Out Period.
At the end of freeze, there is an optional brief period where the water pump is
stopped, but the refrigeration circuit still remains in freeze. This is used to slightly dry the ice prior
to harvest.
Harvest Period.
When the freeze time is reached, the water pump stops (optional). The solenoid
valve (2 and 20) close, the “D” solenoid valve (3) opens and the defrost time begins. As the ice
releases and drops through the ice slide, it is discharged through the side opening. The defrost time
is to be set for the time required to discharge all the ice plus
20 seconds longer (usually 60 seconds to
140 seconds) depending on water pump operation.
! CAUTION !
Make sure all the ice clears the freezer with at least 20 seconds to spare
before the next freeze period begins. This is to prevent refreezing.
! CAUTION !
1 Freezer Section 31 Hot Gas Strainer
2 Liquid Solenoid Valve 32 Regulator
3 2-Position Hot Gas Valve
4 Hot Gas Shut Off Valve
5 Service Valve
6 Gage
7 Thaw Gas Pressure Switch
8 Freezer plate
10 Check Valve
11 Water Pump
12 Blowdown Connection
13 Globe Valve
14 Overflow and Tank drain
15 Float Valve
16 Water Distribution Pan
17 Strainer
18 Gate Valve
20 Suction Solenoid Valve
21 Suction By-pass
22 Flange Union
23
24 Service valve
Piping Nomenclature
TABLE 4-1