Vollrath Stoelting O431, Service Manual

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A. REFRIGERANT RECOVERY
1. Disconnect the machine from electrical supply
before removing any panels for servicing.
2. Remove all panels.
3. Connect the recovery unit to the suction and
discharge service valves of the compressor.
4. Locate the compressor contactor behind the
header panel and disconnect the red wire #90.
5. Wrap electrical tape around wire to insulate it.
6. Remove the belts from the pulleys to allow the
drive motors to spin freely.
7. Connect power to the machine.
8. Turn the Main Power OFF/ON switch and Freezing
Cylinder OFF/ON switches to the ON position.
9. Press the Push To Freeze button on both IntelliTec
controls. This will energize the solenoid valves.
10. Operate the recovery unit per manufacturer’s
instructions
NOTE
If recovery is not completed after 20 minutes, press
the Push To Freeze button again. This will keep the
solenoid valves open.
B. EVACUATING THE REFRIGERATION SYSTEM
1. Close any open ports in the refrigeration system.
2. Connect a vacuum gauge to one of the Schrader
valves next to an evaporator.
3. Connect the evacuation unit to the suction and
discharge service valves of the compressor.
4. Locate the compressor contactor behind the
header panel and disconnect the red wire #90.
5. Wrap electrical tape around wire to insulate it.
6. Remove belts from the pulleys to allow drive
motors to spin freely.
7. Connect power to the machine.
8. Turn the Main Power OFF/ON switch and Freezing
Cylinder OFF/ON switches to the ON position.
9. Press the Push To Freeze button on both IntelliTec
controls. This will energize the solenoid valves
10. Evacuate the system until the gauge reads 300 μ
Hg for 5 continuous minutes.
NOTE
If evacuation is not completed after 20 minutes,
press the Push To Freeze button again. This will
keep the solenoid valves open.
11. If the system will not maintain a standing vacuum
test with the vacuum pump off (gauge increases
towards atmosphere),
fi nd the leak, fi x it, and
evacuate again.
5.3 REFRIGERANT CHARGING
Refer to the following procedures to properly charge
the refrigeration system. Stoelting recommends liquid
refrigerant charging.
NOTE
For qualifi ed service personnel only. Anybody work-
ing with refrigerants must be certifi ed as a Techni-
cian TYPE I as required by 40 CFR 82 Subpart F
and hold all State and/or local refrigerant handling
certifi cations. In addition, all handling, storage, and
disposal of refrigerants must be in accordance with
Environmental Protection Agency (EPA) guidelines
and standards and all State and local guidelines
and standards.
A. Ensure the electrical supply has been removed
before continuing.
B. If the system has been opened or if there was a
leak, refer to Section 5.2 - Refrigerant Recovery
and Evacuation to evacuate the system prior to
charging.
C. Refer to machine’s information plate for total
charge requirements.
NOTE
The refrigeration system of the O431 is critically
charged. Be sure to charge the system to the weight
listed on the machine’s information plate.
D. For liquid refrigerant charging, connect refrigerant
cylinder to the discharge Schrader valve of the
compressor.
E. Energize all fi ve solenoid valves. There are three
liquid line solenoids and two suction line solenoids.
F. Add the proper amount of refrigerant according
to the machine’s information plate.
CAUTION
The solenoid valves must be energized to allow all
refrigerant to be recovered and to prevent injury
when brazing.
WARNING
Hazardous voltage
The Main Freezer Power switch must be placed in
the OFF position when disassembling for servicing.
The machine must be disconnected from electrical
supply before removing any access panel. Failure
to disconnect power before servicing could result
in death or serious injury.