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alumina suction line filter drier is recommended but must be removed after 72 hours. When a single
compressor or tandem is exchanged in the field, it is possible that a major portion of the oil may still
be in the system. While this may not affect the reliability of the replacement compressor, the extra oil
will add to rotor drag and increase power usage.
6.4.2
Start-up of a new or replacement compressor
Rapid charging only on the suction side of a scroll-equipped system can occasionally result in a
temporary no-start condition for the compressor. The reason for this is that, if the flanks of the scrolls
happen to be in a sealed position, rapid pressurisation of the low side without opposing high-side
pressure can cause the scrolls to seal axially. As a result, until the pressures eventually equalise,
the scrolls can be held tightly together preventing rotation. The best way to avoid this situation is to
charge on both the high and low sides simultaneously at a rate which does not result in axial loading
of the scrolls.
A minimum suction pressure specified in the published operating envelope must be maintained
during charging. Allowing the suction pressure to drop below that value may overheat the scrolls and
cause early drive bearing and moving parts damage. Never install a system in the field and leave it
unattended when it has no charge, a holding charge, or with the service valves closed without
securely electrically locking out the system. This will prevent unauthorised personnel from
accidentally operating the system and potentially ruining the compressor by operating with no
refrigerant. Do not start the compressor while the system is in a deep vacuum. Internal arcing
may occur when a scroll compressor is started in a vacuum causing burnout of the internal lead
connections.
6.4.3
Compressor return procedure
Compressors from systems with A1 refrigerant can be sent back to Emerson for diagnosis with closed
connections and the oil filling inside. However, the refrigerant should be removed.
For all systems with A2L refrigerants, if a compressor has to be returned to the manufacturer for
analysis, the refrigerant and the oil have to be removed completely. For the shipping process, all
compressor connections must remain open and warning stickers for flammable refrigerant must be
placed on the shipping box.
▪ During the entire working procedure continuously check if the ambient atmosphere is flammable.
If a flammable atmosphere is detected, ensure proper ventilation of the working space and
immediately cut-off the power supply.
▪ Resume working after the atmosphere is no longer dangerous.
▪ Recover the refrigerant from the system using a suitable recovery unit. During this action, the
compressor crankcase heater could be energized – immediately de-energize in case a flammable
atmosphere is detected.
▪ Recover to 3 mbar absolute pressure or lower. For best results and to recover also the refrigerant
dissolved in the oil, run the recovery unit two or three times as necessary.
▪ Flush the whole system with oxygen-free dry nitrogen.
▪ Open the system with a cutting tool and flush the entire system with dry nitrogen.
▪ Disassemble the compressor with a cutting tool. Drain and recover compressor oil properly. Flush
the compressor with dry nitrogen again for a few minutes.
▪ The compressor should be returned free of oil and with connections open – do not close
connections with plugs.
▪ Collect and secure the oil properly. Provide information about the quantity of oil drained from the
compressor and its colour. Ideally, send a good picture.
▪ Dispose of the oil according to local rules and regulations.
▪ Use a proper cardboard box package when preparing the compressor for shipment. Place
warning icons
the box: "Warning! Flammable A2L refrigerant compressor for analysis".
▪ The compressor must be kept in the upright position – mark the box accordingly.
▪ If more than one compressor have to be returned, each compressor must be packed individually.
NOTE: Check with the transport company that all the requirements that apply to such
shipments are complied with.
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on each side and on the top of the box. Mention the following message on
AGL_Ref_DG_YBDK1E_EN_Rev04
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