Vogt P18AL TUBE-ICE, Service Manual

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P18AL Service Manual
SERVICE OPERATIONS
3/6/07
9-6
Non-condensable Gases. Satisfactory operation of the machine is not possible if non-condensable
gases (usually air) are present in the system. Excessive condensing pressure is an indication of such
gases. Excessive condensing pressure in water cooled condensers may also be due to the
accumulation of scale in the cooling coil or due to insufficient cooling water or excessive water
temperature. See “Water Cooled Condensers”, Section 7.
Purging Non-Condensables
. Air and other non-condensable gases in a refrigeration system are not
desirable. Purging air from your Tube-Ice
®
machine will greatly improve system performance and
save money.
Non-condensable gas effects are:
1.
Higher condensing pressure than desired.
2. Greater electrical power consumption.
3. Reduced refrigeration capacity.
4. Longer than normal compressor running time.
5. Slow ice release and long thaw cycle.
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 line, but should be done only
during the thaw cycle or after the system has been idle at least two hours.
Purging Procedure 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.