Purging Air From Service Hoses
The purpose of this procedure is to remove all the
air trapped in the hoses prior to actual system test-
ing. Environmental regulations require that all ser-
vice hoses have a shutoff valve within 12 inches of
the service end. These valves are required to
ensure only a minimal amount of refrigerant is lost
to the atmosphere. R-134a gauge sets have a com-
bination quick disconnect and shutoff valve on the
high and low sides. The center hose also requires a
valve.
The initial purging is best accomplished when con-
nected to recovery or recycle equipment. With the
center hose connected to the recovery station, ser-
vice hoses connected to the high and low sides of
the system, we can begin the purging. The manifold
valves and service valves should be closed. Activat-
ing the vacuum pump will now pull any air or mois-
ture out of the center hose. This will require only a
few minutes of time. The hose is the only area that
is being placed in a vacuum and this will not require
a lengthy process. Closing the valve will then insure
the hose is purged. It is now safe to open the other
manifold valves.
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