Using Disposable Cans or Refrigerant Drum

Fig. 3 Charging A/C System:

Never use these cans to charge into the high pressure side of the system (compressor discharge port) or into a system that is at high temperature, because the high system pressures could be transferred into the charging can causing it to explode.
If R-12 drum is used, place on scale and note total weight before charging. During charging, watch scale to determine amount of R-12 used.
If 14 ounce R-12 cans are used, close tapping valve, then attach cans following instructions included with manifold adapter.

Charging Of System

1. Start engine and allow to warm up (choke "OFF," normal idle). Set A/C control lever to "OFF."
2. With R-12 drum or cans inverted, open R-12 supply valve and allow 1 lb. of liquid R-12 to flow into system through low-side service fitting on accumulator, Fig. 3.
3. When 1 lb. of refrigerant has entered system, engage compressor by setting A/C lever to NORM and blower switch to HI to draw in remainder of charge. Cooling condenser with a large fan will speed up charging procedure by maintaining condenser temperature below charging cylinder temperature.
4. Close refrigerant supply valve and run engine for 30 seconds to clear lines and gauges.
5. With engine running, remove charging low side hose adapter from accumulator service fitting. Unscrew rapidly to avoid excessive refrigerant loss. Do not remove a gauge line from its adapter when line is connected to A/C system. To disconnect line, always remove line adapter from service fitting. Do not remove charging hose at gauge set while attached to accumulator, as system will be discharged due to depressed Schrader valve.
6. Replace protective cap on accumulator fitting and turn engine "OFF."
7. Check system for leaks.
8. Start engine and check for proper system pressures.