RWB II ROTARY SCREW COMPRESSOR UNITS
MAINTENANCE
070.200-IOM (DEC 11)
Page 43
BARE COMPRESSOR MOUNTING
The following procedure is required only when a bare com‑
pressor is replaced in the field.
1. Thoroughly clean the compressor feet and mounting pads
of burrs and other foreign matter to ensure firm seating of
the compressor.
2. Clean the discharge flange surfaces on the compres sor
and separator.
3. Install a gasket on the compressor discharge connec tion
of the separator.
4. Set the compressor on its base and tighten the dis charge
flange bolts. The feet of the compressor should lift off the
mounting base. If the compressor feet do not raise off
the mounting base install a thicker discharge gasket and
reinstall the discharge flange bolts. Check the clearance
between the feet and the base with a feeler gauge. Shim the
compres sor feet (gauge reading plus .002").
5. Tighten compressor hold down bolts.
6. Complete compressor/motor coupling alignment (see
INSTALLATION section).
7. Complete tubing, piping and wiring per the P & I and wir‑
ing diagrams.
SHUTDOWN DUE TO IMPROPER OIL
PRESSURE (HIGH STAGE and BOOSTER)
The compressor must not operate with incorrect oil
pressure.
1. For units with QUANTUM™LX Control Panels, refer
to CONTROL SETUP ‑ "OIL SETPOINTS DISPLAY" in
090.022‑O.
2. For units with Microprocessor Control Panels, install a
pressure transducer to monitor the pressure of the oil supply
to the balance piston. The correct pressure with the solenoid
closed is 50 psi below discharge pressure (+/‑15 psi). The
correct pressure with the solenoid valve open is within 20 psi
of oil pressure as measured at the oil manifold.
At 60 psi and less differential pressures, with the solenoid
valve closed, the oil pressure should be 1.1 times suction
pressure (+/‑15 psi). Differential pressure is defined as de‑
fined as discharge pressure minus suction pressure.
The shutdown should occur if the condition persists for 2
minutes. For the first 5 minutes after compressor start has
been confirmed, this safety shutdown may be ignored.
3. For units with Electromechanical Control Panels, a safety
shutdown on balance piston oil pressure may be omitted.
GREASE COMPATIBILITY
If it becomes necessary to mix greases, be careful not to
combine different oil bases or thickeners. DO NOT mix a
mineral oil‑base grease with a synthetic oilbase grease. Also,
a grease with a lithium thickener should not be mixed with
one containing a sodium thickener. The table illustrates the
compatibility of various types of grease based on results by
National Lubricating Grease Institute (NLGI). The chart indi‑
cates a great variance in compaibility with the greases tested.
NLGI Grease Compatibility Chart
Install the valve and adjust the spring tension accordingly
to maintain the predetermined oil temperature. The recom‑
mended oil temperature for ammonia is 130°F. Check with
Frick service for recommended oil temperatures for other
refrigerants.
If all of the above steps have been properly performed and
the desired oil temperature can not be achieved, contact
Frick Service.
Aluminum Complex
Barium
Calcium
Calcium 12‑hydroxy
Calcium Complex*
Clay
Lithium
Lithium 12‑hydroxy
Lithium Complex
Polyurea
Aluminum Complex – I I C I I I I C I
Barium I – I C I I I I I I
Calcium I I – C I C C B C I
Calcium 12‑hydroxy C C C – B C C C C I
Calcium Complex I I I B – I I I C C
Clay I I C C I – I I I I
Lithium I I C C I I – C C I
Lithium 12‑hydroxy I I B C I I C – C I
Lithium Complex C I C C C I C C – I
Polyurea*
I I I I
C
I I I I –
B = Borderline Compatibility
C = Compatible
I = Incompatible
* Standard
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