There are two major hazards associated with air conditioning systems and
they both relate to the refrigerant gas. First, the refrigerant gas (R-12)
is an extremely cold substance. When exposed to air, it will instantly freeze
any surface it comes in contact with, including your eyes. The other hazard
relates to fire. Although normally non-toxic, the R-12 gas becomes highly
poisonous in the presence of an open flame. One good whiff of the vapor formed
by burning R-12 can be fatal. Keep all forms of fire (including cigarettes)
well clear of the air conditioning system.
Because of the inherent dangers involved with working on air conditioning
systems and R-12 refrigerant, these safety precautions must be strictly followed.
Avoid contact with a charged refrigeration system, even when working on another
part of the air conditioning system or vehicle. If a heavy tool comes into contact
with a section of tubing or a heat exchanger, it can easily cause the relatively
soft material to rupture.
When it is necessary to apply force to a fitting which contains refrigerant,
as when checking that all system couplings are securely tightened, use a wrench
on both parts of the fitting involved, if possible. This will avoid putting
torque on refrigerant tubing. (It is also advisable to use tube or line wrenches
when tightening these flare nut fittings.)
NOTE: R-12 refrigerant is a chlorofluorocarbon which, when
released into the atmosphere, can contribute to the depletion of the ozone
layer in the upper atmosphere. Ozone filters out harmful radiation from the
sun.
Do not attempt to discharge the system without the proper tools. Precise control
is possible only when using the service gauges and a proper A/C refrigerant
recovery station. Wear protective gloves when connecting or disconnecting service
gauge hoses.
Discharge the system only in a well ventilated area, as high concentrations
of the gas which might accidentally escape can exclude oxygen and act as an
anesthetic. When leak testing or soldering, this is particularly important,
as toxic gas is formed when R-12 contacts any flame.
Never start a system without first verifying that both service valves are
properly installed, and that all fittings throughout the system are snugly connected.
Avoid applying heat to any refrigerant line or storage vessel. Charging may
be aided by using water heated to less than 125°F (50°C) to warm the
refrigerant container. Never allow a refrigerant storage container to sit out
in the sun, or near any other source of heat, such as a radiator or heater.
Always wear goggles to protect your eyes when working on a system. If refrigerant
contacts the eyes, it is advisable in all cases to consult a physician immediately.
Frostbite from liquid refrigerant should be treated by first gradually warming
the area with cool water, and then gently applying petroleum jelly. A physician
should be consulted.
Always keep refrigerant drum fittings capped when not in use. If the container
is equipped with a safety cap to protect the valve, make sure the cap is in
place when the can is not being used. Avoid sudden shock to the drum, which
might occur from dropping it, or from banging a heavy tool against it. Never
carry a drum in the passenger compartment of a vehicle.
Always completely discharge the system into a suitable recovery unit before
painting the vehicle (if the paint is to be baked on), or before welding anywhere
near refrigerant lines.
When servicing the system, minimize the time that any refrigerant line or
fitting is open to the air in order to prevent moisture or dirt from entering
the system. Contaminants such as moisture or dirt can damage internal system
components. Always replace O-rings on lines or fittings which are disconnected.
Prior to installation coat, but do not soak, replacement O-rings with suitable
compressor oil.
