Unit Operation; Operator Responsibilities; Oil Compressor Load - Trane CXAO Installation Operation & Maintenance

Unit operation

4 Unit operation
4.1

Operator Responsibilities

It is important that the operator is properly trained and
become familiar with the equipment before working on
the unit. In addition to reading this manual, the operator
must study the manual operation of the microprocessor
and the wiring diagram to understand the sequence
of start-up, operation, shutdown sequences, and the
criterion of operation of all safety devices. During the
initial start-up of the unit an authorized technician is
available to answer any questions and educate on
the proper functioning. We recommend the operator
to maintain a record of the operating data for each
unit installed. Moreover, another record should be
maintained for all maintenance activities and periodic
service. If the operator checks abnormal or unusual
operating conditions, it is recommended to consult an
authorized technician.
4.2

Oil compressor load

Screw compressor
Oil circuit
The circulation of the oil is obtained by exploiting the
pressure difference between the discharge pressure
and the suction pressure In the starting phase, since the
pressures are always equalized inside the compressor,
there is no circulation of oil, but the bearings and the
screws are designed to tolerate short periods (a few
seconds) of operation "dry" , waiting for it to establish the
necessary pressure difference. The lubricating oil has the
following functions:
• Bearing lubrication
• Dynamic seal between the screws and the
cylindrical chambers
• Control of the sliding drawer (throttle) for
adjusting the capacity
• Cooling of bearings and temperature uniformity
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Inside the compressor the oil is contained in the sump,
fl owing in the lubrication circuit via a fi lter and reaches
the injection points on the bearings and on the screw
and towards the cylinder of the sliding drawer that
regulates the capacity control
Capacity control
Pressure control oil circulation.
The correct amount of oil, so the oil performs all its
functions (lubrication, sealing, sliding drawer control
(throttle), cooling), is ensured when the compressor
operates within the scope set with fi lter normally clean
and oil with its own physical characteristics intact.
The total volumetric fl ow rate of the oil is due to
the operating conditions (pressure) and the type of
refrigerant.
The oil circuit of the compressor is designed for:
• Minimum volumetric fl ow rate of 4 liters / min
(calibration set of the oil fl ow switch)
• Maximum volumetric fl owrate of 24 liters / min
The amount of oil loaded at the factory in the
compressor are listed in the card catalogs and technical.
Depending on the type of plant and the working
conditions of the compressor may be necessary to add a
certain amount of oil to the initial charge. Consider also
the presence of the oil cooling circuit. The oil level in the
compressor must be examined when the compressor is
running. The compressor is equipped with two LEDs to
display the oil level, made on cast iron in the vicinity of
the oil sump.
• The upper indicator indicates the optimal level for
the correct operation
• The lower indicator indicates the minimum level
below which it can not work
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RF-SVX003A-GB