Vogt TUBE-ICE 05TA, Service Manual

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05TA Service Manual
SERVICE OPERATIONS
8/13/01
9-4
Turn the adjusting screws clockwise to raise the pressure setting. Turn counter-clockwise to lower
the setting. Adjust the switch to the indicated pressure settings and test with an accurate gage to be
sure the switch functions properly before installation.
Head Pressure. The head pressure should be maintained at 190-210 psig for R-22 and 230-250 psig
for R-404a during the freeze cycle. This pressure can be checked at the test connection in the high
pressure line near the high-low pressure switch.
Water-Cooled Units.
A water regulating valve (FIGURE 9-3A) located in the condenser water inlet
line is used to control the water flow through the condenser. This valve should be adjusted to
maintain a head pressure of 195 psig for R-22 and 235 psig for R-404a. Increasing the water flow
lowers the head pressure and decreasing the water flow raises the head pressure. The valve is
adjusted during the factory test. The valve stem should not be opened as far as it will go or the valve
will not close fully when the head pressure drops below its setting.
Air-Cooled Units.
The condenser fan switch mounted to the frame (lower right side) (FIGURE 9-
3B) (CPS) is used to regulate the head pressure. This is an adjustable pressure switch located on the
right-hand front of machine. It controls the operation of the condenser fan motor(s) through a
contactor (FC) (FIGURE 6-1) located in the control panel. The switch is set to cycle the fan
motor(s) “On” at 210 psig and “Off” at 190 psig for R-22 and “On” at 250 psig and “Off” at 230 psig
for R-404a. Higher settings may be necessary for 0
°
F and below ambient conditions to assure there is
enough warm gas for ice harvesting.
FIGURE 9-3A. Water Regulating Valve FIGURE 9-3B. Condenser Fan Switch
Compressor Crankcase Heater.
When electrical power is supplied to terminals L1, L2 & L3 of the
control panel, the crankcase heater is energized when the machine is not operating. It is de-energized
when the compressor is operating.
Compressor Motor Protector, Electronic. Copeland compressors using solid state protection have
PTC (Positive Temperature Coefficient) internal sensors with an avalanching resistance in the event of
high temperatures. The sensors are calibrated for proper motor protection.