Before you have opened the system
Beware

When discharging air conditioning system, use only approved refrigerant recovery recycling equipment make sure you make every attempt to avoid discharging refrigerant into the atmosphere.

DISCHARGING THE A/C SYSTEM
The EPA indicates that R-11, R-12 and R-113 are very harmful to the Earths Ozone layer. Make sure you make every attempt possible to avoid discharging R-11, R-12 or R-113 into the atmosphere.
1. Remove service valve and install gauges. For high side gauge hose, Adapter must be used to connect to high side service valve.
2. Slightly open low side gauge valve and let refrigerant escape slowly without loosing refrigerant oil.
3. When system is nearly discharged, using approved refrigerant recovery recycling equipment, open high side gauge valve to release any pressure trapped in compressor. Close valves immediately after discharging to prevent entry of moisture.

DISCONNECTING LINES & FITTINGS
1. After system is discharged, using approved refrigerant recovery recycling equipment, carefully clean entire area around coupling nut to prevent dirt entering system. Always use two wrenches to avoid twisting or distorting lines and fittings
2. Cap or plug all LINES and FITTINGS immediately to prevent entry of air and moisture into system. Do not remove these caps until connections are being made make sure you make every attempt to avoid discharging refrigerant into the atmosphere.

COMPONENT REPLACEMENT
When components are replaced, system oil level must be adjusted. Add refrigeration oil to replacement component. See Compressor oil Check article, as well as, Component Oil Replacement Quantities" chart under "A/C SYSTEM SPECS" article in this HEATER AND AIR CONDITIONING

SYSTEM PRECAUTIONS

Before you have opened the system BE AWARE

When discharging air conditioning system, use only approved refrigerant recovery recycling equipment make sure you make every attempt to avoid discharging refrigerant into the atmosphere.

DISCHARGING THE A/C SYSTEM
The EPA indicates that R-11, R-12 and R-113 are very harmful to the Earths Ozone layer. Make sure you make every attempt possible to avoid discharging R-11, R-12 or R-113 into the atmosphere.
1. Remove service valve and install gauges. For high side gauge hose, Adapter must be used to connect to high side service valve.
2. Slightly open low side gauge valve and let refrigerant escape slowly without losing refrigerant oil.
3. When system is nearly discharged, using approved refrigerant recovery recycling equipment, open high side gauge valve to release any pressure trapped in compressor. Close valves immediately after discharging to prevent entry of moisture.

DISCONNECTING LINES & FITTINGS
1. After system is discharged, using approved refrigerant recovery recycling equipment, carefully clean entire area around coupling nut to prevent dirt entering system. Always use two wrenches to avoid twisting or distorting lines and fittings
2. Cap or plug all LINES and FITTINGS immediately to prevent entry of air and moisture into system. Do not remove these caps until connections are being made make sure you make every attempt to avoid discharging refrigerant into the atmosphere.

COMPONENT REPLACEMENT
When components are replaced, system oil level must be adjusted. Add refrigeration oil to replacement component. See Mercedes oil Check article, as well as, Component Oil Replacement Quantities chart under "A/C SYSTEM SPECS" article in this section.

USING R-12 REFRIGERANT.
1. Always wear eye protection when around air conditioning systems air conditioning systems and R-12. The system's high pressure can cause severe injury to eyes and skin if a hose were to burst. R-12 evaporates quickly when exposed to atmosphere, freezing anything it contacts.
2. Use care when handling refrigerant containers. DO NOT drop or strike containers or expose refrigerant containers to excessive heat. Containers must never be heated more than (52C) 125F. Never expose R-12 directly to open flame.
CAUTION: When R-12 is exposed to an open flame, drawn into a running engine, or detected with a Halide leak tester, poisonous phosgene gas is formed. Keep work areas ventilated.

INDIVIDUAL R-12 CANS
Disposable refrigerant cans have a flat type seal or a screw type seal, and proper can tap must be used for each type. Be sure sealing gasket on can tap is in good condition. A proper safety can tap will prevent refrigerant from flowing back into open can, as tap has a one-way flow control.

MULTI-CAN DISPENSING VALVES
A multi-can dispensing valve allows attachment of several cans of refrigerant, and is a good substitute when a bulk container is not available each leg has its own can tap cans are installed onto each leg of multi-can dispensing valve in the same manner as the individual cans.

CAN TAP INSTALLATION FLAT TYPE SEAL CANS
Recent findings by the EPA indicate that refrigerant is harmful to the Earth's protective Ozone layer. When discharging refrigerant avoid allowing refrigerant to enter the atmosphere. Refrigerant recovery system should be used when discharging the system.
First turn the handle outward to the fully open position. Securely engage locking lugs over the can flange, and lock them in place by turning cam lock or locking nut screw tap assembly into adapter so sealing gasket is fully seated against the can top.

Turn tap inward to pierce the can and close the tap. DO NOT open tap until ready to purge the service hose or dispense refrigerant into the system. Be certain tap handle is turned fully inward to the closed position. Check that locking base is turned to its outer limit. Securely engage locking lugs over the can flange. Turn entire tap assembly downward into the locking base to pierce the can. DO NOT open tap until ready to dispense into system.

DO NOT open high side hand valve while air conditioning system is in operation. This high pressure could rupture can or fitting at safety can valve, resulting in damage and personal injury.

CONNECTING LINES & FITTINGS
A new "O" ring should be used in all instances when connecting lines and fittings. Always use two wrenches to avoid twisting or distorting lines and fittings, tighten coupling nuts securely.

PLACING SYSTEM IN OPERATION
1. Evacuate the system using a vacuum pump.
2. Charge the system with new R-12 according to each individual vehicle to Refrigerant Capacity.
3. Leak test the system, with particular attention to all new connections and components.
4. Make a performance test of the system.

COMPRESSOR REMOVAL INFORMATION
On systems which have compressors equipped with stem-type service valves, it is possible to isolate the compressor for removal.

Turn both high and low pressure manual valves to extreme clockwise position. Loosen cap on high pressure manual valve connection to compressor and allow gas to escape until compressor is relieved of pressure.

COMPRESSOR REMOVAL INFORMATION - DISCHARGE METHOD
This procedure is to be used on vehicles which have compressor equipped with Schrader valves. In these cases, the compressor cannot be isolated and the system must be discharged, using approved refrigerant recycling equipment.

USING R-12 REFRIGERANT.
1. Always wear eye protection when around air conditioning systems and R-12. The system's high pressure can cause severe injury to eyes and skin if a hose were to burst. R-12 evaporates quickly when exposed to atmosphere, freezing anything it contacts.
2. Use care when handling refrigerant containers. DO NOT drop or strike containers or expose refrigerant containers to excessive heat. Containers must never be heated more than (52C) 125F. Never expose R-12 directly to open flame.

CAUTION: When R-12 is exposed to an open flame, drawn into a running engine, or detected with a Halide leak tester, poisonous phosgene gas is formed. Keep work areas ventilated.

INDIVIDUAL R-12 CANS
Disposable refrigerant cans have a flat type seal or a screw type seal, and proper can tap must be used for each type. Be sure sealing gasket on can tap is in good condition. A proper safety can tap will prevent refrigerant from flowing back into open can, as tap has a one-way flow control.

MULTI-CAN DISPENSING VALVES
A multi-can dispensing valve allows attachment of several cans of refrigerant, and is a good substitute when a bulk container is not available each leg has its own can tap cans are installed onto each leg of multi-can dispensing valve in the same manner as the individual cans.

CAN TAP INSTALLATION FLAT TYPE SEAL CANS
Recent findings by the EPA indicate that refrigerant is harmful to the Earth's protective Ozone layer. When discharging refrigerant avoid allowing refrigerant to enter the atmosphere. Refrigerant recovery system should be used when discharging the system.
First turn the handle outward to the fully open position. Securely engage locking lugs over the can flange, and lock them in place by turning cam lock or locking nut. Screw tap assembly into adapter so sealing gasket is fully seated against the top. Turn tap inward to pierce the can and close the tap. DO NOT open tap until ready to purge the service hose or dispense refrigerant into the system.
Be certain tap handle is turned fully inward to the closed position. Check that locking base is turned to its outer limit. Securely engage locking lugs over the can flange. Turn entire tap assembly downward into the locking base to pierce the can. DO NOT open tap until ready to dispense into system.

DO NOT open high side hand valve while air conditioning system is in operation. This high pressure could rupture can or fitting at safety can valve, resulting in damage and personal injury.

CONNECTING LINES & FITTINGS
A new "O" ring should be used in all instances when connecting lines and fittings. Always use two wrenches to avoid twisting or distorting lines and fittings, tighten coupling nuts securely.

PLACING SYSTEM IN OPERATION
1. Evacuate the system using a vacuum pump.
2. Charge the system with new R-12 according to each individual vehicle to Refrigerant Capacity.
3. Leak test the system, with particular attention to all new connections and components.
4. Make a performance test of the system.

COMPRESSOR REMOVAL INFORMATION
On systems which have compressors equipped with stem-type service valves, it is possible to isolate the compressor for removal.

Turn both high and low pressure manual valves to extreme clockwise position. Loosen cap on high pressure manual valve connection to compressor and allow gas to escape until compressor is relieved of pressure.

COMPRESSOR REMOVAL INFORMATION - DISCHARGE METHOD
This procedure is to be used on vehicles which have compressor equipped with Schrader valves. In these cases, the compressor cannot be isolated and the system must be discharged, using approved refrigerant recycling equipment.