Vollrath Stoelting O431, Service Manual

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H. Adjust the hot gas bypass valve to 18 psig ±1.
I. Wait 2 minutes to ensure pressure remains stable.
J. Hand-tighten seal cap to valve.
HOT GAS BYPASS REMOVAL
A. Remove the side and rear panels.
B. Recover refrigerant charge per instructions in
Section 5.2.
C. Remove insulation around hot gas bypass and
tubing.
D. Leave the suction and discharge ports open to
prevent pressure buildup during hot gas bypass
removal.
E. Apply a heat sink (wet cloth) to the hot gas bypass.
F. Unsweat the hot gas bypass and remove.
HOT GAS BYPASS REPLACEMENT
To replace the hot gas bypass, perform the following
procedures:
A.
Apply a heat sink (wet cloth) to the hot gas bypass.
B. With an open port, braze the hot gas bypass into
the system using appropriate brazing material.
C. Remove the heat sink from the hot gas bypass.
D. Replace the fi lter drier. Refer to Section 5.8 for
details.
E. Evacuate and recharge system per instructions
in Section 5.2.
E. WATER VALVE (WATER COOLED MODELS ONLY)
The water valve monitors refrigerant pressure and opens
on an increase of pressure. The opening point pressure
is the refrigerant pressure required to lift the valve disc
off the valve seat. (Figure 5-12)
WATER VALVE ADJUSTMENT
A. Remove the back panel.
B. Connect a gauge to the compressor discharge
Schrader valve.
C. Connect the machine to the electrical supply, start
the refrigeration cycle, and read the pressure.
D. The proper gauge reading should be 225-235 psig.
The exit water temperature should be 95-107°F.
E. If the water temperature and high side pressure
are too low, the opening point pressure should
be increased to slow the water
fl ow. Turn the
adjustment screw counterclockwise.
F. If the water temperature and high side pressure
are too high, the opening point pressure should
be decreased to increase the
fl ow of water. Turn
the adjustment screw clockwise.
WATER VALVE REMOVAL
The water valve is connected to the refrigeration system
by capillary tube brazed to the discharge line.
A.
Turn off and disconnect the water supply. Blow
out the water lines with compressed air or CO
2
.
B. Recover refrigerant charge per instructions in
Section 5.2.
C. Leave the suction and discharge ports open
to prevent pressure buildup during water valve
removal.
D. Unsweat the capillary tube from the discharge
line.
E. Remove the clamps from the water lines at the
valve.
F. Remove the two screws holding the water valve
to the frame and remove the valve.
WATER VALVE REPLACEMENT
To replace the water valve, perform the following proce-
dures:
A.
Position the water valve and attach to the frame
using the two screws.
B. Install the water lines onto the valve with hose
clamps.
C. Leave the suction and discharge ports open
to prevent pressure buildup during water valve
installation.
D. Braze the capillary tube into the system using
appropriate brazing material.
E. Connect the water supply line and turn on the
water supply.
F. Check for leaks in the water lines. If there are no
leaks, turn off the water supply.
G. Replace the fi lter drier. Refer to Section 5.8 for
details.
H. Evacuate and recharge system per instructions
in Section 5.2.
I. Turn on the water and check for leaks in the water
lines with the refrigeration system running.
J. Adjust the valve as necessary.
Figure 5-12 Water Valve