4.1 Suction and Interstage Piping
The suction and interstage manifold should be
piped in such a way that liquid cannot gravity
drain into any compressor. Carlyle recom-
mends that the manifold be located below the
compressor body. An inverted trap must be
used coming off the top of the suction header
if it is above the compressor body. Common
interstage manifolds used in rack applications
must be center fed by the economizer. End
feeding the interstage manifold results in poor
Section 4 — Refrigerant Management System
liquid distribution to the compressors if flooding
occurs. Please see the refrigerant piping schematic
below.
Steel refrigerant piping is not recommended with
screw compressor applications. The contaminant’s
associated with the steel pipe will overload the
3 micron filters used on the oil system causing
excessive and costly filter changes and increasing
the chances of oil related compressor failures.
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HPS
LPS
HPS
LPS
EVAPORATOR
LEAD COMPRESSOR
HPS
LPS
HPS
LPS
OIL SEP.
DISCHARGE
CONDENSER
ECONOMIZER
EXPANSION VALVE
SOLENOID
CHECK VALVE
MOTOR COOLING
VALVE
HPS HIGH PRESSURE
SWITCH
LPS LOW PRESSURE
SWITCH
SYSTEM WITHOUT LIQUID INJECTION INTO ROTORS
(TYPICAL FOR USE WITH OIL COOLERS)