Manual for Refrigeration Servicing Technicians - UNEP - Division of ...

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Refrigerant Management
CHAPITRE 3
PAGE 24
Recovery from a domestic refrigerator
It is possible to recover refrigerant from a hermetically sealed
system, which has no service valve. A line-tap valve (piercing
valve) should be fitted to the system, and a recovery unit used to
remove the refrigerant from the unit via the line-tap as with the
larger system. Line-tap valves should never be left permanently in
place, but removed after use if placed on the process tube (if the
equipment is going for disposal). Because of the small charge of
refrigerant, only vapour recovery is needed.
It is recommended to install tap-valves on both and low pressure side, as
shown here:
Recovery from a domestic refrigerator
Recovery from commercial cold room system
Liquid transfer
Connect the recovery cylinder’s hose to the system’s outlet stop
valve on the condenser/receiver. To control liquid flow, install a
sight glass to the hose and cylinder. From the recovery cylinder’s
vapour side, use a drier. Outlet/discharge side of the recovery unit
goes to the system’s high-pressure side at the inlet condenser
or compressor high-pressure stop valve. All of the system’s stop
valves have to be opened, including the solenoid valves.
Run the recovery unit and keep an eye on the sight glass. When
there is no more liquid transferred through the sight glass, and there
is no icing left on the compressor shell, on the receiver or anywhere
else, this indicates there is negligible amounts of refrigerant left in
the system.
Vapour transfer
When liquid transfer is completed, connect the hoses from the
recovery unit suction/inlet side to the compressor low or highpressure
side. For better recovery, connect hoses to both the high
and low pressure sides using a service manifold. The recovery
discharge/outlet side should be connected to the recovery
cylinder’s vapour side. Be sure that all service/shut off valves are
open to avoid “locking” refrigerant into the system.
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