Subaru R-134A, R-12 manual General Preparations, Discharging, Evacuating

General Preparations

Always conduct a visual inspection of the air conditioning system to identify any damage, excessive wear, refrigerant leaks (oil residue), improper belt adjust- ment, improper pulley alignment, and plugged condenser cooling fins.

Note: Never use water to clean the condenser or radiator fins. Using compressed air is the approved method.

Observe the refrigerant flow through the receiver/dryer sight glass (if equipped), use the correct gauges to check all systems, verify all system compo- nents and controls are operable, check for loose fittings, replace defective, worn, or damaged drive belts, and repair system leaks.

Note: The use of the sight glass alone to determine system charge level can be misleading. Normally operating and correctly charged variable displacement compressors and R-134a systems will have bubbles showing in the sight glass under certain conditions.

Discharging

Caution: Refrigerant R-12 has been identified as a compound which causes damage to the ozone layer. It is unlawful to discharge R-12 into the atmosphere. Subaru of America encourages you to handle R-12 in a responsible and safe manner, and according to Federal EPA guidelines and any local and state regulations. Always follow approved recovery/recycling procedures and utilize approved recovery/recycling equipment.

Discharging and recovery of the system refrigerant is required before replacement of major components of the system. It is also required when the system has a leak, or for the replacement of refrigerant oil. Discharging and recovery of the system refrigerant is the first step in preparing for major servicing, repair,

or replacement of components; the second step is evacuation.

Evacuating

Evacuating the system removes air and moisture from the system. Discharge and recover the system refrigerant first; then follow the steps listed below to evacuate the system:

•Fully close both valves of the manifold gauge set.

•Connect a vacuum pump to the center charging hose of the manifold gauge set.

•Start the vacuum pump.

•Open the low- and high pressure valves slowly.

•When the pressure reading has reached approximately 29.00 in Hg, fully close both valves.

•Stop the vacuum pump.

•Wait 10 minutes, the pressure reading should not change. If it changes, there is a leak in the system.

Note: Certain types of system leaks such as loose fittings may not be discovered using this method. Always recheck the system with a leak detector after the system is charged.

	Evacuating The System
Elevation		Vacuum of System
m (ft)		mm Hg, in Hg
0 (0)	710		27.95
300 (1,000)	685		26.97
600 (2,000)	660		25.98
900 (3,000)	635		25.00

Note: Values show readings of the low-pressure gauge.

Elevation/Pressure Relationship

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