Heating and Air Conditioning: Fundamentals and Basics

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 system.
- Switch on existing exhaust/ventilation systems when working on the refrigerant system.
- Discharge A/C system before removing any refrigerant system component.
- Always use an Underwrite's Laboratory (UL) approved refrigerant recovery/recycling /recharging unit such as Kent-Moore ACR4, or equivalent, whenever 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 O-rings, DO NOT reuse. Use only the correct size and type of O-rings specified for use with R-134a refrigerant Lubricate O-ring with refrigerant (PAG) 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 become contaminated with moisture or if the container has been left open.
- Always reinstall cap(s) over A/C service valve(s).

Flush Refrigerant System With Compressed Air And Nitrogen (available Locally) If:
- Moisture or dirt have entered the refrigerant system (i.e. following an accident).
- Refrigerant oil is dark and thick
- Too much refrigerant oil is in the system following compressor replacement.
- The compressor is replaced due to internal damage (i.e. noises).

When Flushing The Refrigerant System:
- DO NOT flush the refrigerant system with R-71.
- Evacuate the refrigerant system for a minimum of 30 minutes.

CAUTION:
- DO NOT top-off a charged refrigerant system instead, discharge, evacuate and recharge the system.
- After system recharge, manually rotate A/C compressor approx. 10 turns before starting engine. Start engine with A/C OFF After idle speed has stabilized, switch A/C ON and let engine idle (compressor running) for a minimum of two minutes before raising engine speed.

NOTES:
- For information on A/C wiring See Electrical Wiring Diagrams, Testing and Inspection and Locations (Components).
- A/C refrigerant system safety measures, [1][2]Service Precautions.
- Green label in engine compartment indicates A/C system is charged with refrigerant R-134a.