Heating and Air Conditioning: Fundamentals and Basics

Basics When Working On Refrigerant System R-134a

CAUTION:
- Keep work area and all tools clean.
- Use only tools, equipment and parts specified for use with R-134a.
- Always wear protective glasses and gloves when working on A/C refrigerant system.
- Switch on existing exhaust and ventilation systems when working on the refrigerant system.
- Discharge A/C system before removing any A/C refrigerant system component.
- Always use an Underwriter's Laboratory (UL) approved refrigerant recovery, recycling and recharging unit, such as Kent- Moore ACR4, or equivalent when discharging an R-134a A/C system.
- Immediately plug open connections on A/C components to prevent dirt and moisture contamination. Likewise, do not remove new component from packaging until ready to install. Immediately tighten component connections after installation.
- Always replace 0-rings, do not reuse. Use only the correct size and type of 0-rings specified for R-134a refrigerant. Lubricate 0-ring with R-134a refrigerant oil before installing.
- Use only the specified PAG oil from a sealed container and always reseal oil container immediately after use. Do not use oil if it has been contaminated with moisture or if the container has been left open.
- Always reinstall caps over A/C service valves.
- Do not flush refrigerant system with R-11.
- Evacuate refrigerant system for a minimum of 30 minutes.
- After system recharge, manually rotate A/C compressor. approximately 10 turns before starting engine. Start the engine with A/C switched off. After the idle speed has stabilized, switch A/C on and let engine idle (compressor running) for at least two minutes before raising engine speed.
- Do not top-off a charged refrigerant system. Instead, discharge, evacuate and recharge system.

Note:
- For information on A/C wiring see applicable wiring diagram.
- See also A/C refrigerant system safety measures. [1][2]Service Precautions
- Green label in engine compartment indicates that A/C system is charged with R-134a refrigerant.
- Only a high pressure service valve is used for A/C system servicing A low pressure service valve is not installed in the A/C system. Perform all A/C system service operations such as discharging, evacuating, recharging through the high pressure service valve only.