5
1.5 Ambient Conditions
The screw compressor is designed for the
following specified ambient temperature ranges:
Non-Operating
-40°F To 130°F
(-40°C To 54°C)
Start-Up
-40°F To 130°F
(-40°C To 54°C)
Operating
-25°F To 130°F
(-32°C To 54°C)
1.6 Installation Environment
The intended installation modes for the screw
compressor are:
Machine Rooms—Enclosed Atmosphere
External Environment—Sheet Metal Enclosure
NOTE: The electrical terminal box is not
approved for external applications.
1.7 Pressure Relief Valve
All compressor models contain an automatic
reset high pressure relief valve. The pressure
relief valve is located inside the compressor and
will internally vent the compressor discharge
to the compressor suction when it relieves.
The valve opens at a pressure differential of
400 psi (27.6 bar). The relief valve is not
field serviceable.
1.8 Discharge Check Valve
All compressor models are supplied with an
internal discharge check valve. This check
valve prevents the reverse flow of refrigerant
through the compressor during compressor off
cycles. A check valve in the discharge line is
not required for parallel applications. It may be
required for pump down on single compressor
systems.
The discharge check valve is field serviceable.
1.9 Compressor Inlet Screens
Filter screens are applied at all locations where
liquid or gas enters the compressor, i.e., suc-
tion, economizer and oil connections.
For systems that operate below -25F (-32c), it
is recommended that the suction screen be
removed after 48 hours of system startup as
the viscous oil can damage the screen.
The compressor inlet screens are field
serviceable and available through Carlyle
distribution.
1.10 Service Valves
Suction and discharge connections will
interface with the 2-1/2" bolt pattern service
valves currently being used on the Carlyle
reciprocating compressors. Rotalock
®
service
valves are used for the economizer line shut
off. The line sizes are as follows:
Connection Size
Connection
Max.
Min.
Suction
1-5/8"
1-1/8"
Discharge
1-5/8"
1-1/8"
Economizer
7/8"
7/8"
All compressor models are supplied with the 1-5/8"
suction and discharge service valves and the 7/8"
economizer valve.
All 05T compressors and 06T compressors
between 65cfm and 88cfm use a barstock
service valve, (06TA680008) which is physically
larger than the standard service valve
(06TA660001) used on all 06T compressors
between 33cfm - 54cfm (see compressor
physical dimensions on pages 2 & 3).
1.11 Condenser Pressure Control
Important!
Large variations in head pressure will
result in very poor oil separation which
may result in nuisance oil level switch
tripping. The condenser pressure must
be controlled such that fluctuations are
gradual. Carlyle screw compressors
must be applied with a minimum of one
condenser fan (preferably variable speed)
active at all times and a means of minimum
head pressure control for low ambient
operation. For alternate methods of con-
denser control, please contact Carlyle
Application Engineering.
