7–5
T-340
7.6 Evacuation and Dehydration
7.6.1
General
Moisture is detrimental to refrigeration systems. The presence of moisture in a refrigeration system can have many
undesirable effects. The most common are copper plating, acid sludge formation, “freezing-up” of metering devices
by free water, and formation of acids, resulting in metal corrosion.
7.6.2
Preparation
1. Evacuate and dehydrate only after pressure leak test (see
).
2. Essential tools to properly evacuate and dehydrate any system include a vacuum pump (8m3/hr = 5 cfm vol
-
ume displacement) and an electronic vacuum gauge. The pump is available from Carrier Transicold, P/N
07-00176-11. The micron gauge is P/N 07- 00414- 00.
3. If possible, keep the ambient temperature above 15.6°C (60°F) to speed evaporation of moisture. If the
ambient temperature is lower than 15.6°C (60°F), ice might form before moisture removal is complete. Heat
lamps or alternate sources of heat may be used to raise the system temperature.
4. Additional time may be saved during a complete system pump down by replacing the filter drier with a sec
-
tion of copper tubing and the appropriate fittings. Installation of a new drier may be performed during the
charging procedure.
Figure 7.4 Refrigeration System Service Connections
1) Liquid Service Connection
2) Receiver or Water Cooled Condenser
3) Compressor
4) Discharge Service Connection
5) Suction Service Connection
6) Vacuum Pump
7) Electronic Vacuum Gauge
8) Manifold Gauge Set
9) Refrigerant Cylinder
10) Reclaimer
- - - - -
7.6.3
Evacuate and Dehydrate - Complete System
NOTE
Refer to Partial System procedure for information pertaining to partial system evacuation and dehydration.
1. Remove all refrigerant using a refrigerant recovery system.
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