Vogt P18AL TUBE-ICE, Service Manual

Page: 71 / 88

P18AL Service Manual
SERVICE OPERATIONS
3/6/07
9-7
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 (22). 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.
Oil Trap Draining Procedure
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.
Removing Excess Water from Ammonia
If excessive water is in the ammonia, it will cause frost on the suction line to the compressor, and
dilution of the oil. This condition should not go uncorrected and the water needs to be removed.
Water Removal Procedure
1.
Perform a total pumpdown of the freezer. See “Pumpdown” page 9-4.
2. A total pumpdown is accomplished when there is no frost or ice on the freezer or oil trap and the
freezer pressure is below that pressure relative to the surrounding temperature. Refer to the
Temperature-Pressure chart for ammonia.
3. With the freezer pressure below 25 PSIG, attach a hose to the oil trap drain valve and extend the
other end into a container (5 gallon bucket, etc.).
4. Open the drain valve a little and drain out the oil and water that is present.
5. Continue to drain oil/water, and purge the freezer and compressor to 0 PSIG.