Never smoke or have any open flame when working with the air conditioning system.
Never open or loosen a connection before discharging the system properly.
When loosening a connection, if any residual pressure is evident, allow it to leak off before opening the fitting fully.
Keep service tools and work area clean.
Before disconnecting a component from the system, clean the outside of the fittings thoroughly.
A system which has been opened to replace a component or one which has discharged through leakage must be evacuated before charging the system.
Immediately after disconnecting a component from the system, seal the open fittings with a cap or plug.
Before connecting an open fitting, always install a new seal ring. Coat the seal with refrigerant oil before connecting.
Because of the potential risk to the environment, many regions of the country have tight regulations as to the service or repair of A/C systems. Before serving any part of the A/C system, check with the local authorities as to what regulations apply.
Fig. Fig. 1: Air conditioning system configuration