070.750-IOM2 (JUN 22)
Page 14
HPS 273 and 407 Rotary Screw Compressor
Installation
Other connections are available for instrumentation and
service as noted on the compressor connections and di-
mensional outline drawing. See Figure 11 and Figure 12.
Note: Total pressure drop is the difference between dis-
charge pressure and oil pressure at the compressor
ports.
This is critical for the correct operation of the balance
piston, which is used to ensure the life of the male and
female axial bearing.
Compressor oil
Warning
Do not mix oils of different brands, manufacturers, or
types. Mixing of oils can cause excessive oil foaming,
nuisance oil level cutouts, oil pressure loss, gas or oil
leakage, and catastrophic compressor failure. Cool-
Ware selects a specic Frick oil for the refrigerant
being used. Depending on the application, a differ-
ent oil can be selected, provided it is of the correct
viscosity and is compatible with the refrigerant and
compressor elastomers.
Notice
Bare compressors are usually shipped without an oil
charge. The oil specified for the compressor opera-
tion is critical. Select the appropriate oil based on
requirements in 160.802-SPC, Compressor Oil Speci-
cations.
Oil system
The entire oil supply system for the compressor must be
designed for a total pressure drop of no more than 1.0 bar
(14.5 psig) with a new oil lter element. This is critical for
the correct operation of the balance piston, which ensures
the life of the male and female axial bearing.
Note: Total pressure drop is the difference between dis-
charge pressure and oil pressure at the compressor
ports.
Oil pump
If your HPS compressor application requires an oil pump,
mount a strainer upstream because this can protect the
pump.
Oil heaters: heating wires and
insulation
Your package must be equipped with oil heaters that
provide sufcient heat to prevent condensation from oc-
curring during startup and shutdown cycles. Insulate the
whole system.
Oil filters
Johnson Controls-Frick engineering must approve in writ-
ing the use of lter elements other than Johnson Controls-
Frick, or a warranty claim may be denied. Oil lter speci-
cation b
5
= 75 according to ISO 4572 is required to obtain
oil cleanliness class 16/14/11 according to ISO 4406.
Oil cooling requirements
Compressor oil needs to be cooled to control the dis-
charge temperature, maintain correct oil viscosity, and
to preserve the life of the oil. The discharge temperature
depends on application and operation conditions. Refer to
CoolWare. For a CO
2
compressor, it is usually around
60°C (140°F). For an ammonia heat pump, it can be
120°C (250°F) or higher.
There are applications that it is normal to have discharge
temperatures as high as 150°C (300°F) An ammonia heat
pump is one example. The higher discharge temperature
permits higher process uid temperatures to be achieved.
Another application that can require higher discharge
temperatures as high as 150°C (300°F) is natural gas
gathering at the wellhead. Moisture is present in the gas
and it is imperative that the discharge temperature is least
17°C (30°F) higher than the dew point of the component,
including water vapor, within the gas stream that has the
highest discharge dew point temperature.
Notice
The discharge temperature requirement is at any load-
ing
and capacity, any speed, not only at full load.
1. Open CoolWare and from the Wet/Dry Mode list, se-
lect Water Saturated.
2. Select Calculate to get the discharge dew point tem-
perature for your application.
Oil temperatures as high as 130°C (266°F) can achieve
the necessary discharge temperature to prevent moisture
from condensing in the oil separator. Contact Johnson
Controls–Frick for additional information for natural gas
compression.
The main oil injection line that connects to port SM-1 or
SM-2 must have a regulating valve so it can adjust the oil
ow to maintain the appropriate discharge temperature
at all times. A non-return valve is also required in order
to prevent gas from owing backward into the oil system
under start-up and transition of operating conditions
The regulating valve may need to have a motor so the
actual opening or ow can be controlled by the control
panel. This is often necessary for heat pumps where a
certain capacity, water temperature, and efciency is
expected. It may also be a requirement when the speed
turndown is signicant, from 4,200 rpm to 1,000 rpm for
example for HPS 273 models, because the relative oil ow
may get too high at the lower speed range. Turndown
above 3 requires an automatic valve. Consult CoolWare
and the factory.
When considering minimum supply oil temperature, do
not use a thermostatic three-way bypass mixing valve. For
alternate methods consult Frick Engineering.
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