VOGT ICE TUBE-ICE P-24A, Service Manual

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P24A & P34A Service Manual
SERVICING OPERATIONS
12/18/12
9-19
Air collects mostly in high pressure condensers, receivers, and other high-pressure components. It
collects mostly in the coolest, lowest-velocity area of these components.
Evaporative condensers usually have purge points at the top of the outlet header of each circuit.
Receivers usually have a purge point at the top, away from the inlet, where it is coolest and the gas
velocity is the lowest.
The freezer can be purged through the valve at the top of the suction accumulator, but should be
done only during the thaw cycle or after the system has been idle at least two hours.
Follow this procedure when purging:
1. Connect a suitable hose to the purge valve and place the other end in water.
2. Open (slightly) the purge valve and allow air to escape.
3. Air will appear as bubbles in the water rising to the surface.
4. The larger the bubbles, the more air is escaping.
5. DO NOT leave the purge hose unattended.
6. When air bubbles are reduced to a minute size (smaller than 1/16), it can be considered that most
of the air has escaped and purging can be ceased at this point.
7. Additional purging can be done at other purge points.
8. When purging is completed, close the valve, disconnect the hose, and install a plug in the purge
valve.
Draining the Oil Trap.
After many hours of operation, the oil which escapes the oil separator will
pass through the receiver and to the freezer where it will settle in the oil trap, #36. Indication of oil
in the trap will be evident by the frost line. At the end of a freeze cycle, frost (or ice) will form on
that part of the oil trap where oil is not present. When frost is seen only on the top 1/4 to 1/2 of the
oil trap, the oil trap should be drained. Do not allow the oil trap to fill completely with oil, or it will
cause loss of ice production and possible refrigerant floodback to the compressor.
1. Stop the machine and wait 12 hours or more.
2. Attach a suitable hose to the oil trap drain valve #61. Make sure there are no kinks or restrictions
in the hose.
3. Open the valve slightly until oil begins to drain.
4. Continually observe the oil flow, being ready to close the valve quickly.
! DANGER !
Do not leave the oil trap drain valve opened or unattended--severe injury may result
! DANGER !
5. When a small amount of liquid ammonia begins to spew out, immediately close the valve.
6. Remove the hose and install a plug in the valve. DO NOT attempt to reuse any oil taken from
the system unless it is properly reclaimed and meets the proper specifications.