Gardner Denver ELECTRA-SAVER G2 Service manual

13-21-611
Version: 00
January 7, 2019
ELECTRA-SAVER G2 &
ELECTRA-SAVER II G2
STATIONARY BASE-MOUNTED
COMPRESSOR
AirSmart™G2 Controller
CONFIGURATOR
SAV75-100G2A - 75, 100 HP
ST75-100G2A - 75, 100 HP
OPERATING AND
SERVICE MANUAL

13-21-611 Page 1
MAINTAIN COMPRESSOR RELIABILITY AND PERFORMANCE WITH
GENUINE GARDNER DENVER® COMPRESSOR PARTS AND SUPPORT SERVICES
Gardner Denver® Compressor genuine parts, manufactured to design tolerances, are developed for optimum
dependability –specifically for Gardner Denver compressor systems. Design and material innovations are the result
of years of experience with hundreds of different compressor applications. Reliability in materials and quality assurance
is incorporated in our genuine replacement parts.
Your authorized Gardner Denver Compressor distributor offers all the backup you’ll need. An AirSmartnetwork of
authorized distributors provides the finest product support in the air compressor industry.
Your authorized distributor can support your Gardner Denver air compressor with these services:
1. Trained parts specialists to assist you in selecting the correct replacement parts.
2. Factory warranted new and remanufactured rotary screw airends. Most popular model remanufactured
airends are maintained in stock at the factory, for purchase on an exchange basis with liberal core credit
available for the replacement unit.
3. A full line of factory tested AEON™ compressor lubricants specifically formulated for use in Gardner Denver
compressors.
4. Repair and maintenance kits designed with the necessary parts to simplify servicing your compressor.
Authorized distributor service technicians are factory trained and skilled in compressor maintenance and repair. They
are ready to respond and assist you by providing fast, expert maintenance and repair services.
To Contact Gardner Denver or locate your local distributor:
visit: www.contactgd.com/compressors
or
call: [phone]
INSTRUCTIONS FOR ORDERING REPAIR PARTS/REMANUFACTURED AIRENDS
Whenever an airend requires replacement or repair, Gardner Denver offers an industry unique, factory remanufactured
airend exchange program. From its modern factory, Gardner Denver is committed to supplying you with the highest
quality, factory remanufactured airends that are guaranteed to save you time, aggravation and money
When ordering parts, specify Compressor MODEL, Method of Cooling, POWER and SERIAL NUMBER (see nameplate
on unit). The Airend Serial Numbers are also stamped on top of the discharge bearing carrier castings.
All orders for Parts should be placed with the nearest authorized distributor.
Where NOT specified, quantity of parts required per compressor or unit is one (1); where more than one is required per
unit, quantity is indicated in parenthesis. SPECIFY EXACTLY THE NUMBER OF PARTS REQUIRED.
DO NOT ORDER BY SETS OR GROUPS.
To determine the Right-Hand and Left-Hand side of a compressor, stand at the motor end and look toward the
compressor. Right-Hand and Left- Hand are indicated in parenthesis following the part name, i.e. (RH) and (LH), when
appropriate.

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WARNING –PROHIBITION –MANDATORY LABEL INFORMATION
Gardner Denver Rotary Screw compressors are the result of advanced engineering and skilled
manufacturing. To be assured of receiving maximum service from this machine, the owner must exercise
care in its operation and maintenance. This book is written to give the operator and maintenance
department essential information for day-to-day operation, maintenance and adjustment. Careful
adherence to these instructions will result in economical operation and minimum downtime.
Boxed text formats are used, within this manual, to alert users of the following
conditions:
Safety Labels are used, within this manual and affixed to the appropriate areas of
the compressor package, to alert users of the following conditions:
Indicates a hazard with a high level of risk, which if not avoided, WILL result in death or serious
injury.
Equipment starts automatically
Cutting of Finger or Hand Hazard –Rotating
impeller blade
Cutting of Finger or Hand Hazard –Rotating fan
blade
Health Hazard –Explosive Release of Pressure
High Voltage –Hazard of Shock, Burn, or Death
Present until Electrical Power is Removed
Entanglement of Fingers or Hand/Rotating Shaft

13-21-611 Page 3
Indicates a hazard with a medium level of risk which, if not avoided, COULD result in death or
serious injury.
Asphyxiation Hazard –Poisonous Fumes or Toxic Gases in Compressed Air
Indicates a hazard with a low level of risk which, if not avoided, MAY result in a minor or
moderate injury.
Burn Hazard –Hot surface
PROHIBITION/MANDATORY ACTION REQUIREMENTS
Do not Operate Compressor with Guard
Removed
Do Not Lift Equipment with Hook –No Lift Point
Handle Package at Forklift Points Only
Lockout Electrical Equipment in De-Energized
State
Loud Noise Hazard –Wear Ear Protection
Read the Operator’s Manual Before Proceeding
with Task

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SAFETY PRECAUTIONS
Safety is everybody’s business and is based on your use of good common sense. All situations or
circumstances cannot always be predicted and covered by established rules. Therefore, use your past
experience, watch out for safety hazards and be cautious. Some general safety precautions are given
below:
Failure to observe these notices could result in injury to or death of personnel.
Keep fingers and clothing away from rotating fan, drive coupling, etc.
Disconnect the compressor unit from its power source, lockout and tagout before working on the
unit –this machine is automatically controlled and may start at any time.
Do not loosen or remove the oil filler plug, drain plugs, covers, the thermostatic mixing valve or
break any connections, etc., in the compressor air or oil system until the unit is shut down and
the air pressure has been relieved.
Electrical shock can and may be fatal.
Perform all wiring in accordance with the National Electrical Code (NFPA-70) and any applicable
local electrical codes. Wiring and electrical service must be performed only by qualified
electricians.
Open main disconnect switch, lockout and tagout before working on the control, wait 10 minutes
and check for voltage.
Failure to observe these notices could result in damage to equipment.
Stop the unit if any repairs or adjustments on or around the compressor are required.
Do not use the air discharge from this unit for breathing –not suitable for human consumption.
An Excess Flow Valve should be on all compressed air supply hoses exceeding 1/2 inch
inside diameter (OSHA Regulation, Section 1926.302).
Do not exceed the rated maximum pressure values shown on the nameplate.
Do not operate unit if safety devices are not operating properly. Check periodically. Never
bypass safety devices.

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TABLE OF CONTENTS
Maintain Compressor Reliability And Performance With Genuine Gardner Denver Compressor Parts And
Support Services...........................................................................................................................................1
Instructions For Ordering Repair Parts/Remanufactured Airends................................................................1
Warning –Prohibition –Mandatory Label Information..................................................................................2
Safety Precautions........................................................................................................................................4
Index..............................................................................................................................................................6
List Of Illustrations.........................................................................................................................................7
Section 1, General Information .....................................................................................................................8
Section 2, Installation..................................................................................................................................12
Section 3, Starting & Operating Procedures...............................................................................................22
Section 4, Controls & Instrumentation ........................................................................................................33
Section 5, Lubrication, Oil Cooler, Oil Filter & Separator............................................................................66
Section 6, Air Filter......................................................................................................................................87
Section 7, Coupling.....................................................................................................................................89
Section 8, Maintenance Schedule ..............................................................................................................92
Section 9, Troubleshooting .........................................................................................................................95
This book covers the following models:
HP
PSIG
Model
Parts List
Controller Manual
75, 100
100, 125, 150
SAV75-100G2A
13-21-504
13-17-613
75, 100
100, 125, 150, 175, 200
ST75-100G2A
13-21-504
13-17-613

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INDEX
Addition Of Oil Between Changes......................................74
Air Filter Element Life ........................................................88
Air Filter Vacuum Switch....................................................37
Air Filter, Heavy Duty (Standard).......................................87
Air Flow In The Compressor System....................................8
Air-Cooled Units, Location.................................................13
Auxiliary Air Receiver.........................................................16
Blowdown Valve................................................................35
Blowdown Valve Piping .....................................................17
Cold Ambient Operation ....................................................74
Cold Weather Operation....................................................15
Cold Weather Operation, Installation For...........................15
Compression Principle.........................................................8
Compressor.........................................................................8
Compressor Oil Cooler - Water-Cooled Heat Exchanger ...80
Control Piping....................................................................16
Controls & Instrumentation
Airsmart G2 Controller Operation..................................33
General Description.......................................................33
Cooling, Sealing And Lubrication.........................................9
Coupling............................................................................89
Daily Check.......................................................................24
Electrical Wiring.................................................................20
Emergency Stop Push-Button............................................38
Fan Starter ........................................................................39
Filter Element ....................................................................87
Foundation ........................................................................14
Fuse Blocks.......................................................................39
Grounding..........................................................................20
Heat Exchanger (Oil) Piping ..............................................72
High Temperature Operation.............................................67
Inlet Line............................................................................16
Inlet Tube ..........................................................................88
Inlet Valve..........................................................................36
Installation For Cold Weather Operation............................15
Lifting Unit .........................................................................12
Location.............................................................................12
Air-Cooled Units............................................................13
Water-Cooled Units.......................................................14
Lubricant
Recommended..............................................................66
Lubricant Change Procedure.............................................74
Lubrication
Motor.............................................................................21
Main Starter.......................................................................39
Minimum Discharge Pressure Valve..................................35
Moisture In The Oil System................................................67
Moisture Separator/Trap....................................................16
Oil Change Interval............................................................75
Oil Cooler - Radiator Type.................................................80
Oil Filter.............................................................................79
Oil Level Gauge.................................................................75
Oil Reservoir......................................................................83
Drain.............................................................................14
Filling ............................................................................78
Oil Sampling Valve............................................................76
Oil Separator
Compressor (GD Eliminator) .........................................83
Inspection.....................................................................84
Oil Carryover ................................................................ 83
Pressure Differential Gauging.......................................84
Removal For Inspection Or Replacement .....................85
Oil Specifications............................................................... 66
Oil System
Compressor..................................................................66
Draining And Cleaning.................................................. 77
Oil System Check.............................................................. 85
Air And Oil Discharge Temperature .............................. 85
Oil Cooler Oil Pressure Differential (Air-Cooled Radiator)
.................................................................................86
Oil Cooler Oil Pressure Differential (Water-Cooled Heat
Exchanger)............................................................... 86
Oil Cooler Temperature Differential (Air-Cooled Radiator)
.................................................................................86
Oil Cooler Temperature Differential (Water-Cooled Heat
Exchanger)............................................................... 86
Oil Cooler Water Pressure Differential (Water-Cooled
Heat Exchanger) ......................................................86
Oil Inlet Pressure.......................................................... 85
Oil Inlet Temperature....................................................85
Piping
Water Piping (Parallel).................................................. 20
Water Piping (Series)....................................................19
Power Supply....................................................................39
Pressure Regulator........................................................... 36
Pressure Transducer
Plant Delivery ............................................................... 37
Reservoir......................................................................37
Separator...................................................................... 37
Prestart-Up Instructions.....................................................22
Quick Start Guide (Controller)........................................... 25
Remote Mounted Elevated Cooler Assembly ....................71
Safety Precautions..............................................................4
Service Check List ............................................................92
Every 1000 Hours Operation.........................................92
Every 125 Hours Operation...........................................92
Every 8 Hours Operation .............................................. 92
Every 2000 Hours Operation.........................................92
Service Check List ...........................................................93
Shuttle Valve.....................................................................36
Solenoid Valves IVC And IVO...........................................36
Starting The Unit............................................................... 24
Unit Cold.......................................................................24
Unit Hot ........................................................................24
Stopping The Unit ............................................................. 24
Temperature Sensor
Discharge..................................................................... 38
Separator...................................................................... 38
Terminal Strip....................................................................39
Thermal Control (Thermostatic Mixing) Valve....................80
Warning –Prohibition –Mandatory Label Information .........2
Water Flow Control Valve For Heat Exchanger .................82
Water Piping ..................................................................... 18
Water Shutoff Valve - Water-Cooled Heat Exchanger .......83

13-21-611 Page 7
LIST OF ILLUSTRATIONS
Figure 1-1 –Compression Cycle....................................................................................................................................8
Figure 1-2 –Starter Box.................................................................................................................................................9
Figure 1-3 –Control Box................................................................................................................................................9
Figure 1-4 –Compressor / Motor Side.........................................................................................................................10
Figure 1-5 –Cooler / Reservoir Side............................................................................................................................10
Figure 1-6 –Air/Oil Flow Diagram................................................................................................................................11
Figure 2-1 –Typical Compressor Room ......................................................................................................................13
Figure 2-2 –Air Flow Chart..........................................................................................................................................13
Figure 2-3 –Cold Weather Installation.........................................................................................................................15
Figure 2-4 –Inlet Line Lengths.....................................................................................................................................16
Figure 2 5 –Heat Exchanger (Oil Cooler) Approximate Water Flow............................................................................17
Figure 2-6 –Aftercooler Approximate Water Flow .......................................................................................................18
Figure 2-7 –Series Piping............................................................................................................................................19
Figure 2-8 –Parallel Piping..........................................................................................................................................19
Figure 4-1 –Controller Keypad....................................................................................................................................33
Figure 4- 2–Schematic Tubing Diagram......................................................................................................................34
Figure 4- 3–Minimum Discharge Pressure/Check Valve.............................................................................................35
Figure 4- 4–Turn Valve - Electra Saver Only ..............................................................................................................37
Figure 4- 5–Compressor Package P&ID.....................................................................................................................41
Figure 4- 6–Compressor Package Control Component States ...................................................................................42
Figure 4- 7–Electra Saver Wiring Diagrams................................................................................................................43
Figure 4- 8–Electra Saver II Wiring Diagrams.............................................................................................................43
Figure 4- 9–Wiring Diagram –WYE DELTA (AIR–COOLED / WATER–COOLED)....................................................44
Figure 4- 10–Wiring Diagram –WYE DELTA (AIR–COOLED / WATER–COOLED)..................................................53
Figure 5-1 –Dew Point Chart F..................................................................................................................................68
Figure 5-2 –Dew Point Chart C..................................................................................................................................68
Figure 5-3 –Flow Diagram –Air/Oil System................................................................................................................69
Figure 5-4 –Oil Flow Diagram –Remote Overhead Mounted Cooler..........................................................................70
Figure 5-5 –Oil Level Gauge.......................................................................................................................................75
Figure 5-6 –Oil Change Interval..................................................................................................................................76
Figure 5-7 –Oil Sampling Valve Location....................................................................................................................76
Figure 5-8 –Approximate Oil System Capacities.........................................................................................................78
Figure 5-9 –Thermostatic Mixing Valve Element.........................................................................................................80
Figure 5-10 –Water Control Valve...............................................................................................................................81
Figure 5-11 –Oil Separator..........................................................................................................................................83
Figure 6-1 –Heavy Duty Air Filter................................................................................................................................87
Figure 7-1 –Installation Of Coupling Cushions............................................................................................................89
Figure 7-2 –Installation Of Coupling Cushions............................................................................................................90

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8
1-1
SECTION 1
GENERAL INFORMATION
Figure 1-1 –COMPRESSION CYCLE
COMPRESSOR - The Gardner Denver Rotary Screw compressor is a single stage, positive displacement
rotary machine using meshing helical rotors to effect compression. Both rotors are supported between high
capacity roller bearings located outside the compression chamber. Single width cylindrical roller bearings
are used at the inlet end of the rotors to carry part of the radial loads. Tapered roller bearings at the
discharge end locate each rotor axially and carry all thrust loads and the remainder of the radial loads.
COMPRESSION PRINCIPLE (Figure 1-1) - Compression is accomplished by the main and secondary rotors
synchronously meshing in a one-piece cylinder. The main rotor has five (5) helical lobes 72apart. The
secondary rotor has six (6) matching helical grooves 60apart to allow meshing with main rotor lobes.
The air inlet port is located on top of the compressor cylinder near the drive shaft end. The discharge port
is near the bottom at the opposite end of the compressor cylinder. It is then routed to the top of the
integrated cast housing. Figure 1-1 is an inverted view to show inlet and discharge ports. The compression
cycle begins as rotors unmesh at the inlet port and air is drawn into the cavity between the main rotor lobes
and secondary rotor grooves (A). When the rotors pass the inlet port cutoff, air is trapped in the interlobe
cavity and flows axially with the meshing rotors (B). As meshing continues, more of the main rotor lobe
enters the secondary rotor groove, normal volume is reduced and pressure increases.
Oil is injected into the cylinder to remove the heat of compression and seal internal clearances. Volume
reduction and pressure increase continues until the air/oil mixture trapped in the interlobe cavity by the
rotors passes the discharge port and is released to the oil reservoir (C). Each rotor cavity follows the same
“fill-compress-discharge” cycle in rapid succession to produce a discharge air flow that is continuous,
smooth and shock free.
AIR FLOW IN THE COMPRESSOR SYSTEM (Figure 5-3, page 69) - Air enters the air filter and passes
through the inlet unloader valve to the compressor. After compression, the air/oil mixture passes into the
oil reservoir where most of the entrained oil is removed by velocity change and impingement and drops
back into the reservoir. The air and remaining oil passes into the separator and separator housing where
the oil is separated and passes through tubing connecting the separator housing and compressor. The air
passes through the minimum pressure valve, discharge check valve and cooler, then to the plant air lines.
301EBD797-A
(Ref. Drawing)

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9
1-2
LUBRICATION, COOLING AND SEALING - Oil is forced by air pressure from the oil reservoir through the
oil cooler, thermostatic mixing valve, and oil filter and discharges into the compressor main oil gallery. A
portion of the oil is directed through internal passages to the bearings, gears and shaft oil seal. The balance
of the oil is injected directly into the compression chamber to remove heat of compression, seal internal
clearances and lubricate the rotors.
Figure 1-2 –STARTER BOX
Figure 1-3 –CONTROL BOX
309EBD797
(Ref. Drawing)

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10
1-3
Figure 1-4 –COMPRESSOR / MOTOR SIDE
Figure 1-5 –COOLER / RESERVOIR SIDE
309EBD797-B
(Ref. Drawing)

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11
1-4
Figure 1-6 –AIR/OIL FLOW DIAGRAM
307EBD797-B
(Ref. Drawing)

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12
2-1
SECTION 2
INSTALLATION
GENERAL - On receipt of the unit, check for any damage that may have been incurred during transit.
Report any damage or missing parts as soon as possible
Do not electric weld on the compressor or base; bearings can be damaged by
passage of current.
LIFTING UNIT - Proper lifting and/or transporting methods must be used to prevent damage. Lifting slots
are provided in the base for tow motor use. The unit may also be moved into location by rolling on bars.
Lift compressor package by base only. Do not use other places such as motors,
compressors or discharge manifold piping as lifting points.
The eyebolts or lugs provided on the motors are for lifting the motors only and
should not be used to lift any additional weight. All eyebolts must be securely
tightened. When lifting the motors, the lifting angle must not exceed 15 degrees.
Failure to observe this warning may result in damage to equipment or personal
injury.
Compressor, air/oil reservoir, separator chamber and all piping and tubing may
be at high temperature during and after operation.
LOCATION - The compressor should be installed, whenever possible, in a clean, well-lighted, well-
ventilated area with ample space all around for maintenance. Select a location that provides a cool, clean,
dry source of air. In some cases it may be necessary to install the air filter at some distance from the
compressor to obtain proper air supply.

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2-2
Both the air-cooled and water-cooled units require cooling air as well as air to the compressor inlet. Proper
ventilation MUST be provided; hot air must be exhausted from the compressor operating area. A typical
inlet-outlet air flow arrangement is shown in Figure 2-1.
Figure 2-1 –TYPICAL COMPRESSOR ROOM
Air-Cooled Units - A combination oil/aftercooler is supplied as standard equipment on all air-cooled units.
The air-cooled unit with the standard enclosure requires sufficient flow, Figure 2-2, for the compressor
oil/after cooling system and for electric motor cooling. Air is drawn into the unit at the motor side of the
enclosure and is exhausted at the oil cooler side. Do not block the air flow to and from the unit. Allow three
and one-half (3-1/2) feet (1.1 M) to the nearest obstruction on the starter end and control box end of the
unit. Allow three (3-1/2) feet (1.1 M) to the nearest obstruction above and on other sides of unit. For
continuous efficiency, oil cooler cores must be periodically cleaned with either vacuum or compressed air.
If wet cleaning is required, shield motor and spray on a mild soap solution and flush with clean water.
Minimum Air Flow * For Compression and Cooling –Cubic Feet/Minute
(Cubic Meters/Minute)
HP (kW)
Air Cooled
Water Cooled
75 HP
7114 (202)
1621 (46)
100 HP
7141 (202
1621 (46)
* 80F (27C) Inlet Air
Figure 2-2 –AIR FLOW CHART

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14
2-3
For aluminum oil coolers, do not use any cleaning solution that is not compatible
with aluminum. Use of improper solution may result in damage to the cooler.
Water-Cooled Units - The water-cooled unit with the standard enclosure requires sufficient air flow, Figure
2-2, for electric motor cooling. Air is drawn into the unit at the top of the enclosure and is exhausted at the
motor side. Do not block air flow to and from unit. Allow three and one-half (3-1/2) feet (1.1 m) to the
nearest obstruction on the starter end and control box side of the unit. Allow three (3-1/2) feet (1.1 m) to
the nearest obstruction above and on other sides of the unit.
FOUNDATION - The Gardner Denver Rotary Screw compressor requires no special foundation, but should
be mounted on a smooth, solid surface. Whenever possible install the unit near level. Temporary
installation may be made at a maximum 10angle lengthwise or 10sidewise.
Mounting bolts are not normally required. However, installation conditions such as piping rigidity, angle of
tilt, or danger of shifting from outside vibration or moving vehicles may require the use of mounting bolts
and shims to provide uniform support for the base.
OIL RESERVOIR DRAIN - The oil drain is piped from the bottom of the reservoir with a ball valve and a
flexible hose.
If the compressor unit base is raised above floor level, the space between the
floor and the base bottom must be closed with solid material all around to prevent
recirculation of hot air from the oil cooler end and over temperature operation.
ENCLOSURE - The compressor, electric motor, oil cooler and aftercooler are mounted inside the
enclosure. Service doors are provided for maintenance access. Be sure to allow enough space around
the unit for the doors to open completely. Any of the enclosure doors may be removed by opening the door
and lifting it up slightly to disengage the hinges.
Do not operate the compressor with the fan and coupling guard removed.
Exposed fan and couplings may cause injury to personnel.

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2-4
Figure 2-3 –COLD WEATHER INSTALLATION
INSTALLATION FOR COLD WEATHER OPERATION (Figure 2-3) - It is recommended that the unit be
installed inside a shelter that will be heated to temperatures above freezing (32F, 0C). This will eliminate
many of the problems associated with operating units in cold climates where freezing rain, drifting snow,
freezing condensate and bitter cold temperatures are encountered.
Refer to Engineering Data Sheet 13-9-411 for the advantages of using the heat recovered from rotary
compressors. This heat recovery could easily pay for an adequate shelter for the unit.
When an outside installation must be made, the precautions required will depend on the severity of the
environment. The following are general guidelines for outside installations:
Cold Weather (Down To +10F, -12C)
1. Be sure all drains, traps, and control lines, including pressure transducer lines are heated to avoid
freezing of condensate. Heat tape with thermostat control is generally satisfactory for this purpose
and can be obtained at various local plumbing or hardware outlets at nominal cost.
2. If an air-cooled aftercooler is to be used, provisions to bypass the aftercooler must be made. Since
cold air contains very little moisture, successful operation can be achieved without the aftercooler.
3. Provide at least some simple shelter such as a plywood windbreak to protect against drifting snow.
4. Use only Gardner Denver AEON 9000 SP lubricant.
5. Monitor the unit carefully during start-up and operation to be sure it is functioning normally.

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16
2-5
Extreme Cold Weather Operation (Down To -10F, -23C)
In addition to the above, the following should be provided:
1. It will be necessary to provide shutters or to block off part of the cooler in some manner since the
cooler is greatly oversized for operation in these low temperatures. Since shutters are not provided
as a factory option, blocking off a portion of the cooler with plywood should be satisfactory.
2. Auto operation should not be used in extreme environments.
3. Some means of providing heat during shutdown. Start-up should be provided. There are various
methods to accomplish this, but since openings are not provided for sump heaters, the use of radiant
heaters is recommended. The heaters should be sized to provide at least a +10F (-12 C) environment
for coolers, motor and sump. Figure 2-3, page15, shows how these might be located in a typical
installation and sizes required.
Remember unsheltered (outside) installations should be avoided where possible. Installation next to a
heated building where enough heat can be used to keep the compressor room above freezing will save
many complications in the operation and installation of the unit.
Refer to Engineering Data Sheet 13-9-411, available from an authorized Gardner Denver distributor, for the
advantages of using the heat recovered from rotary compressors. This heat recovery could easily pay for
an adequate shelter for the unit.
AUXILIARY AIR RECEIVER - An auxiliary air receiver is not required if the piping system is large and
provides sufficient storage capacity to prevent rapid cycling. When used, an air receiver should be of
adequate size, provided with a relief valve of proper setting, a pressure gauge and a means of draining
condensate.
MOISTURE SEPARATOR/TRAP –The unit can be provided with an optional stand-alone combination
moisture separator and trap that is field-installed downstream of the aftercooler. The moisture separator
and trap are not required, but are strongly recommended due to the built-in aftercooler.
CONTROL PIPING - Control piping is not necessary since the Rotary Screw compressor unit is factory
wired and piped for the control system specified.
INLET LINE - Where an inlet line is used between the air filter and the compressor, it must be thoroughly
cleaned on the inside to prevent dirt or scale from entering the compressor. If welded construction is
used, the line must be shot blasted and cleaned to remove welding scale. In either case, the inlet line
must be coated internally by galvanizing or painting with a moisture and oil-proof sealing lacquer. Up to
ten (10) feet (3 meters) in length, the inlet line should be the full size of the inlet opening on the compressor.
If an extra-long line is necessary, the pipe size should be increased according to Inlet Line Length Chart,
Figure 2-4, page 16.
Accessibility for inlet air filter servicing must be considered when relocating the filters from the unit to a
remote location.
INLET LINE LENGTHS
Length of Inlet Line
Diameter of Pipe Size
0 to 10 Feet (0 to 3 Meters)....................
Same as Compressor Inlet Opening
10 to 17 Feet (3 to 5 Meters)...................
One Size Larger Than Inlet Opening
17 to 38 Feet (5 to 11.5 Meters)..............
Two Sizes Larger Than Inlet Opening
Figure 2-4 –INLET LINE LENGTHS

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2-6
DISCHARGE SERVICE LINE - The discharge service line connection on both water-cooled and air-cooled
units is made at the right hand corner of the unit, viewed from the opposite end from control panel side.
When two or more rotary screw units are manifolded on the same line, each unit should be isolated by a
check valve in the unit discharge line. If a rotary screw unit is manifolded to another compressor, be sure
the other compressor has a check valve in the line between the machine and the manifold. If a rotaryscrew
and a reciprocating compressor are manifolded together, an air receiver must be located between the two
units.
Discharge air used for breathing will cause severe injury or death.
Consult filtration specialists for additional filtration and treatment equipment to
meet health and safety standards.
BLOWDOWN VALVE PIPING - The blowdown valve is piped back into the airend between the inlet valve
and air filter.
HEAT EXCHANGER
Water Temperature to Heat
Exchanger
Gallons/minute
(Minimum)
Maximum Water
Flow
Gallons/minute *
Approximate Water
Pressure Drop @ 90F
Water Temperature PSI
HP
Model
60F
70F
80F
90F
75
SAV75-100G2A
10.6
12.2
14.3
17.4
26
9.6
100
SAV75-100G2A
14.1
16.2
19.1
23.2
26
17
75
ST75-100G2A
10.6
12.2
14.3
17.4
26
9.6
100
ST75-100G2A
14.1
16.2
19.1
17.4
26
17
* Flows exceeding "Maximum Water Flow" will cause severe erosion and will void unit warranty.
Figure 2-5 –HEAT EXCHANGER (OIL COOLER) APPROXIMATE WATER FLOW

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2-7
AFTERCOOLER
Water Temperature to Heat
Exchanger
Gallons/minute
(Minimum)
Maximum Water
Flow
Gallons/minute *
Approximate Water
Pressure Drop @ 90F
Water Temperature PSI
HP
Model
60F
70F
80F
90F
75
SAV75-100G2A
2.2
2.5
2.9
3.6
26
Less than 1 PSI for any
flow rate shown in the table
100
SAV75-100G2A
2.9
3.3
3.9
4.7
26
75
ST75-100G2A
2.2
2.5
2.9
3.6
26
100
ST75-100G2A
2.9
3.3
3.9
4.7
26
* Flows exceeding "Maximum Water Flow" will cause severe erosion and will void unit warranty.
Figure-2-6 –AFTERCOOLER APPROXIMATE WATER FLOW
WATER PIPING (Water-Cooled Heat Exchanger Models Only) - On machines equipped with water-
cooled heat exchangers, the water inlet and outlet connections are located in the unit enclosure flange on
the end of the unit opposite the control box.
It is mandatory that any water cooled unit be installed in a shelter heated to
temperatures above freezing (32F., 0C).
The water source should be capable of supplying up to the maximum flow shown in Figure 2-5, Page 17,
and Figure-2-6, page18, at a minimum pressure of 40 psig (2.8 bar); maximum allowable water pressure is
150 psig (10.3 bar). The water flow rates shown are approximate and a guide to sizing piping, cooling
tower and other water system equipment.

13-21-611 Page
19
2-8
The heat exchanger system is designed to operate with water inlet temperatures from 60F to 90F (16
C to 32C) and a water outlet temperature not to exceed 110F (43C). If water colder than 60F is used,
high water outlet temperatures (over 110F, 43C) will be experienced along with shortened heat
exchanger life caused by tube fouling and corrosion. If water warmer than 90F (32C) is used, higher
compressor oil inlet temperatures and high water usage will result.
Most water systems will require control of impurities: filtration, softening or other treatment. See Section 5,
“Compressor Oil Cooler - Water-Cooled Heat Exchanger” for more information on the water system.
Figure 2-7 –SERIES PIPING
SERIES PIPING (Figure 2-7) - Water flow must be through aftercooler first for effective cooling of discharge
air and is so piped on the standard water-cooled unit.
Figure 2-8 –PARALLEL PIPING
304EBD797-C
(Ref. Drawing)
304EBD797-C
(Ref. Drawing)