Hot Gas Bypass - Stoelting F431 Service Manual

HIGH PRESSURE CUTOUT REMOVAL
A. Remove the left side and top panels.
B. Recover refrigerant charge per instructions in
Section 5.2.
C. Leave the suction and discharge ports open to
prevent pressure buildup during removal.
D. Unsweat capillary tube from suction line.
E. Remove two screws from top of machine (Refer
to Figure 5-6).
Figure 5-6 High Pressure Cutout Removal
F. Disconnect terminals from high pressure cutout.
HIGH PRESSURE CUTOUT REPLACEMENT
A. With the suction and discharge ports open, braze
the capillary tube to the discharge line.
C. Replace the drier per the instructions in Section
5.9.
D. Braze bulb into place on suction line.
E. Evacuate the system per the instructions in Section
5.2.
F. Recharge the system per the instructions in
Section 5.3.
G. Connect the pink wire to the COM terminal and
the brown/gray wires to the #2 terminal.
H. Attach the high pressure cutout to the top of the
inside of the header panel using the two screws
with star washers.
D. HOT GAS BYPASS
The hot gas bypass valve is installed in parallel to the
compressor and helps to regulate the compressor tem-
perature (Refer to Figure 5-7). When the cab evaporator
is the only part of the system requiring refrigerant, the
bypass valve will allow discharge gas to bypass into the
suction line to prevent liquid refrigerant from entering the
compressor.
Figure 5-7 Hot Gas Bypass
HOT GAS BYPASS ADJUSTMENT
Before adjusting the hot gas bypass, check the EPR
valve and adjust if necessary.
A. Turn the Main Power OFF/ON switch and both
Freezing Cylinder OFF/ON switches in the OFF
position.
B. Connect a gauge to the Schrader valve on the
suction line next to the compressor.
C. Open the cab door and place a piece of tape on
the cab door interlock switch.
The cab door remains open for this test. The rela-
tively warm ambient air will keep the cab refrigera-
tion running.
D. Turn the Main Power OFF/ON switch to the ON
position.
E. Wait 5 minutes to allow the gauge to stop moving.
F. Unscrew the seal cap from the top of the valve.
G Using a 5/16" Allen wrench, adjust the valve
counterclockwise to decrease pressure and
clockwise to increase pressure. (Refer to Figure
5-8)
38
NOTE
NOTE