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

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Refrigerant Management
Recovery from air-conditioning system
Liquid transfer
Air-conditioning installations may have service stop valves installed
in the pipe lines. When recovering refrigerant from such a system,
liquid should be transferred first because the quantity can be rather
large. The push-pull method is recommended.
The system’s liquid pipe should be connected to the recovery
cylinder’s liquid side. The cylinder’s vapour side should be
connected to the recovery inlet (suction) side. The discharge side
recovery unit should be connected to the suction pipe on the air
conditioning system. If there are available valves on the systems
receiver (on the high pressure side), the recovery unit discharge side
could be connected here as well. Liquid flows now from the liquid
side of the air-conditioning system and into in the cylinder. The
recovery unit will keep the pressure inside the cylinder lower than in
the air-conditioning system and keep up the liquid flow.
Vapour transfer
When liquid transfer is completed there will still be some refrigerant
vapour left in the system. To transfer all refrigerant to the recovery
cylinder, connect the suction hose from the recovery unit to the
gas pipe on the air-conditioning system. Connect the recovery unit
discharge outlet hose to the recovery cylinder’s vapour side. Run
the recovery unit until the suction gauge reads –0.7 bar (0.3 bar
absolute) or lower.
Recovery from mobile air conditioning (MAC) system
Vapour transfer
MAC systems are normally equipped with service valves on the
compressor’s high and low-pressure sides. The refrigerant charge
on such system is rather small and therefore only vapour transfer
is required. Connect the hose from the recovery unit’s suction/
inlet side to the air-conditioning system’s compressor low-pressure
side and the discharge hose to the vapour valve on the recovery
cylinders. Run the recovery unit for 3 – 5 minutes. Connect another
hose to the system’s high-pressure side and complete the recovery.
Run the recovery unit until pressure gauges reads –0.7 bar (0.3 bar
absolute) or lower.
Refrigerant reclaiming
Reclamation means to reprocess used refrigerant, typically
by distillation, to conditions similar to that of virgin product
specifications. Reclamation removes contaminants such as
water, chloride, acidity, high boiling residue, particulates/solids,
non-condensable, and impurities including other refrigerants.
Chemical analysis of the refrigerant shall be required to determine
that appropriate specifications are met. The identification of
contaminants and required chemical analysis shall be specified by
reference to national or international standards for new product
specifications. Reclamation typically occurs at a reprocessing or
manufacturing facility. Commercial units are available for use with
R12, R22, R134a, etc, and are designed for the continuous use
required on a long run recovery recycling procedure.
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