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VSG & VSSG
Single Screw Bare Shaft Compressor
TM
The World’s Best Compressors
For Gas Compression
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Important Message
READ CAREFULLY BEFORE INSTALLING AND STARTING YOUR COMPRESSOR.
The following instructions have been prepared to assist in installation, operation and removal of Vilter Single
Screw Compressors. Following these instructions will result in a long life of the compressor with satisfactory
operation.
The entire manual should be reviewed before attempting to install, operate, service or repair the compressor.
A compressor is a positive displacement machine. It is designed to compress gas. The compressor must
not be subjected to liquid carry over. Care must be exercised in properly designing and maintaining the
system to prevent conditions that could lead to liquid carry over. Vilter Manufacturing is not responsible
for the system or the controls needed to prevent liquid carry over and as such Vilter Manufacturing cannot warrant equipment damaged by improperly protected or operating systems.
Vilter screw compressor components are thoroughly inspected at the factory. However, damage can occur
in shipment. For this reason, the equipment should be thoroughly inspected upon arrival. Any damage
noted should be reported immediately to the Transportation Company. This way, an authorized agent
can examine the unit, determine the extent of damage and take necessary steps to rectify the claim with
no serious or costly delays. At the same time, the local Vilter representative or the home office should
be notified of any claim made.
All inquires should include the Vilter sales order number, compressor serial and model number. These can be
found on the compressor name plate on the compressor.
All requests for information, services or parts should be directed to:
Vilter Manufacturing LLC
Customer Service Department
P.O. Box 8904
5555 South Packard Ave
Cudahy, WI 53110-8904 USA
Telephone: 1-414-744-0111
Fax:1-414-744-3483
e-mail: info.vilter@emerson.com
Equipment Identification Numbers:
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
Vilter Order Number: _______________________Compressor Serial Number: _________________
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Table of Contents
Important Message ............................................................................................ 3
VSG STANDARD VILTER WARRANTY STATEMENT ................................................ 6
Long Term Storage Requirements ....................................................................... 7
Critical Applications Guidelines ........................................................................... 8
Instrumentation Requirements ...................................................................... 9
Alarm and Shutdown Readings ..................................................................... 11
VSG Package Requirements .............................................................................. 12
Description .................................................................................................. 13
installation ................................................................................................... 16
Installation & Calibration of Slide Valve Actuators ............................................. 18
Slide Valve Operation ................................................................................... 21
Slide Valve Actuator Trouble Shooting Guide ................................................ 22
Operation Section ............................................................................................ 26
Notice on using Non -Vilter Oils .................................................................... 26
Maintenance ................................................................................................ 29
Service ............................................................................................................. 30
Parts Section .................................................................................................... 57
Gate Rotor ................................................................................................... 58
Shaft Seal ..................................................................................................... 62
Tandem Shaft Seal ........................................................................................ 63
Main Rotor ................................................................................................... 64
Slide Valve Cross Shafts and End Plate .......................................................... 66
Slide Valve Carriage Assembly ...................................................................... 68
Actuator & Command Shaft ......................................................................... 72
Miscellaneous Frame Components ............................................................... 74
Replacement Tools ....................................................................................... 78
VSG 301-701 Replacement Parts Section .......................................................... 81
Gaterotor Assembly ..................................................................................... 82
Shaft Seal ..................................................................................................... 85
Main Rotor, Slide Valve Cross Shafts & End Plate ........................................... 86
Slide Valve Carriage Assembly ...................................................................... 90
Actuator & Command Shaft ......................................................................... 92
Miscellaneous Frame Components ............................................................... 94
Replacement Tools ....................................................................................... 98
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VSG STANDARD VILTER WARRANTY STATEMENT
Seller warrants all new single screw gas compression units and bareshaft single screw compressors
manufactured by it and supplied to Buyer to be free from defects in materials and workmanship for a period
of (a) eighteen (18) months from the date of shipment or (b) twelve (12) months from the date of
installation at the end user’s location, whichever occurs first.
If within such period any such product shall be proved to Seller’s satisfaction to be defective, such product
shall be repaired or replaced at Seller’s option. Such repair or replacement shall be Seller’s sole obligation
and Buyer’s exclusive remedy hereunder and shall be conditioned upon (a) Seller’s receiving written notice
of any alleged defect within ten (10) days after its discovery, (b) payment in full of all amounts owed by
Buyer to Seller and (c) at Seller’s option, Buyer shall have delivered such products to Seller, all expenses
prepaid to its factory. Expenses incurred by Buyer in repairing or replacing any defective product
(including, without limitation, labor, lost refrigerant or gas and freight costs) will not be allowed except by
written permission of Seller. Further, Seller shall not be liable for any other direct, indirect, consequential,
incidental, or special damages arising out of a breach of warranty.
This warranty is only applicable to products properly maintained and used according to Seller’s
instructions. This warranty does not apply (i) to ordinary wear and tear, damage caused by corrosion,
misuse, overloading, neglect, improper use or operation (including, without limitation, operation beyond
rated capacity), substitution of parts not approved by Seller, accident or alteration, as determined by Seller
or (ii) if the product is operated on a gas with an H2S level above 100 PPM. In addition, Seller does not
warrant that any equipment and features meet the requirements of any local, state or federal laws or
regulations. Products supplied by Seller hereunder which are manufactured by someone else are not
warranted by Seller in any way, but Seller agrees to assign to Buyer any warranty rights in such products
that Seller may have from the original manufacturer. Labor and expenses for repair are not covered by
warranty.
THE WARRANTY CONTAINED HEREIN IS EXCLUSIVE AND IN LIEU OF ALL OTHER REPRESENTATIONS AND
WARRANTIES, EXPRESS OR IMPLIED, AND SELLER EXPRESSLY DISCLAIMS AND EXCLUDES ANY IMPLIED
WARRANTY OF MERCHANTABILITY OR IMPLIED WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE.
Any description of the products, whether in writing or made orally by Seller or Seller’s agents,
specifications, samples, models, bulletins, drawings, diagrams, engineering sheets or similar materials used
in connection with Buyer’s order are for the sole purpose of identifying the products and shall not be
construed as an express warranty. Any suggestions by Seller or Seller’s agents regarding use, application or
suitability of the products shall not be construed as an express warranty unless confirmed to be such in
writing by Seller.
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Long Term Storage Requirements
Note: At the time of purchase Vilter Manufacturing must be notified.
1. The compressor(s) must be stored in a heated building, preferably air conditioned to control
moisture, to prevent corrosion of the main rotor shaft and for the compressor. The slide valve
(volume ratio& capacity) motors and gears.
2. The main rotor shaft must be coated with light grease to prevent rusting.
3. (For Screw Compressors) The volume and capacity slide valve motor enclosures should have
corrosion inhibitors installed in them and the enclosures should be sealed. On a six month basis
(depending on relative humidity), check and replace inhibitors as necessary, and check for
signs of corrosion.
4. Before leaving Vilter Manufacturing the compressor is evacuated and pressurized, with dry
nitrogen, to 5 psig. Pressure must be monitored with the gauge (provided by Vilter) and checked
on a regular basis (at least monthly).
5. The rotor shaft must be rotated every 3 months to prevent flat spots from developing on the
bearing surfaces and to keep the shaft seal lubricated.
6. A log should be maintained indicating that the above procedures have been completed.
When the compressor is installed.
A. Look into the suction and discharge connections and inspect for any signs of corrosion on parts.
B. Prelube the compressor with the main oil pump and rotate by hand several revolutions prior to
start.
C. Notify the Vilter Warranty Department when the compressor is started.
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Critical Applications Guidelines
To ensure the successful operation of the VSG compressor, the guidelines described below
should be followed.
1. Proper lubrication is critical to the operation of the VSG compressor. The compressor relies on
the injected oil to absorb and remove the heat of compression, to seal the compression chambers
formed in the flutes of the screw, and to lubricate all moving parts. For this reason, it is imperative that the oil chosen be of correct viscosity, and that sufficient oil flow be provided at all times,
using an auxiliary oil pump when necessary. The oil chosen must be compatible with the process
gas as well, to prevent absorption of the gas into the oil, which would dilute the oil and reduce the
viscosity. Also, oil filtration to 25 micron nominal particle size is required to ensure that only clean
oil is injected into the compressor. For assistance in choosing the correct oil for the application
and in sizing an auxiliary oil pump, consult a Vilter representative.
2. Injection oil temperature must be closely controlled for optimum performance. Oil temperature
must be maintained a minimum of 15 - 20°F above the gas mixture dewpoint at anytime to prevent
condensation or liquid knockout from occurring within the compressor.
Gas composition plays a role in the performance of the VSG compressor as well. While the VSG is
capable of handling a wide variety of gases, it is required that the concentration of H2S in the process gas not exceed 100 PPM. If H2S is present in the process gas in any concentration, special oil
additives are required to protect the compressor from corrosion.
Notice on using Non -Vilter Oils
Oil and its additives are crucial in refrigeration system performance. Vilter Manufacturing will NOT
APPROVE non-Vilter oils for use with Vilter compressors. Due to the innumerable choices available
it is not possible for us to test all oils offered in the market place, and their effects on our equipment,
as we can with our own lubricants.
We realize that customers may choose compressor lubricants other than Vilter branded oil. This is
certainly within the customers’ right as owners of the equipment. When this choice is made, however,
Vilter is unable to accept responsibility for any detrimental affects those lubricants may have on the
equipment or system performance and durability.
Should a lubrication related system issue occur with the use of non-Vilter oils, Vilter may deny warranty upon evaluation of the issue. This includes any parts’ failure caused by inadequate lubrication.
Certainly, there are many good refrigeration lubricants in the market place. The choice of a lubricant
for a particular application involves consideration of many aspects of the lubricant and how it and its
additive package, will react in the various parts of the entire refrigeration system. It is a complex choice
that depends on a combination of field experience, lab and field-testing, and knowledge of lubricant
chosen. Vilter will not accept those risks other than for our own compressor lubricants.
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Instrumentation Requirements
Pressure
There are four pressure transducers required to read
system pressures as listed below.
1. Suction pressure transducer (-15.0 - 300 PSIG)
measures the gas suction pressure into the compressor housing, which provides the permissive
to start for minimum suction pressure, and is
used for annunciation of low suction pressure
while running and in the capacity control logic.
2. Discharge pressure transducer (-15.0 - 300 PSIG)
measures the discharge pressure of the process
gas in the separator, which provides annunciation for high discharge pressure, and may also
be used for capacity control logic.
3. Oil Filter Inlet pressure transducer (-15.0 - 300
PSIG) measures the oil pressure as it enters the
oil filter canisters and is used to calculate oil filter
differential pressure to provide annunciation of
high filter differential pressure
4. Oil Manifold pressure transducer (-15.0 - 300
PSIG) measures the oil pressure downstream of
the oil filter as the oil is injected into the compressor, and provides annunciation protection
for low prelube oil pressure, and low running oil
injection pressure.
Additional pressure transducers may be required and
installed by the customer for pressure readings at customer specified points such as process gas discharge
pressure from the package boundary, cooling water
pressure to and/or from the oil cooler, etc.
Temperature
There are four temperature readings required for
processor control, as listed below.
5. Suction temperature RTD measures the temperature of the incoming suction gas, and is
used to provide annunciation for low suction
temperature when the unit is running.
6. Discharge temperature RTD measures the
temperature of the gas/oil mixture as it is discharged from the compressor housing, and provides annunciation for high running discharge
temperature.
7. Oil Separator temperature RTD measures the
temperature of the oil in the separator sump,
and gives the oil temperature start permissive
and low running separator temperature annunciation.
8. Oil Injection temperature RTD measures the
temperature of the oil as it is injected into the
compressor, which provides annunciation for
either high or low running oil injection temperature.
* Additional RTD’s may be required and installed
by the customer for temperature readings at
customer specified points such as discharge gas
temperature from the package boundary, cooling
water temperature to and/or from the oil cooler,
gas aftercooler temperature, etc.
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OPTIONAL DUAL OIL FILTERS
Instrumentation Requirements
MOTOR
COMPRESSOR
STANDARD SINGLE
OIL FILTER
OIL COOLER
OIL SEPARATOR
STANDARD WATER COOLED OIL COOLER
OPTIONAL REMOTE AIR COOLED OIL COOLER
Miscellaneous: Additional instrumentation devices required are a current transformer mounted around one
phase of the drive motor leads to measure main motor amperage, and two rotary potentiometers to read the
position of the slides. The amperage signal provides annunciation for high motor amperage, and is used in the
capacity control logic. The rotary potentiometers indicate the position of the slides, which is used as a starting permissive and in the capacity control logic. Also, additional input points may be required for customer
connection of remote signals such as Start and Stop commands, and capacity setpoint control.
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Alarm and Shutdown Readings
The control system for the VSG compressor must protect the
machine from damage caused by running outside of normal
operating conditions by providing operators with alarms
when operating parameters have reached an abnormal
condition, and by automatically stopping the compressor
before these conditions can cause a unit failure. Pressures
and temperatures of the process gas and the oil, as well as
motor amperage and slide positions must all be continuously
monitored to ensure the compressor is operating properly.
1. Low Gas Suction Temperature - This point protects
the compressor from suction gas entering the compressor at too low of a temperature, and is activated
by a direct reading from the suction temperature
RTD located in the suction “T”.
2. High Gas Discharge Temperature - This point protects the compressor against high gas temperature at the discharge of the unit, and is activated
by a direct reading from the RTD located in the
compressor discharge manifold.
3. Low Oil Separator Start Temperature - This point
protects the compressor from starting with low oil
temperature in the separator, and is activated by a
direct reading from the RTD located in the bottom
of the oil separator.
4. Low Oil Separator Run Temperature - Similar to
the Low Oil Separator Start Temperature described
above, however this point only becomes active after
a predetermined period of running time, and uses a
higher setpoint.
5. Low Oil Injection Temperature - This point protects
the compressor from running with cold oil being
injected into the screw housing, and is activated by
a direct reading from the RTD located in the oil injection line. This point is bypassed for a predetermined
period of time after starting to allow the unit time
to start and warm up.
6. High Oil Injection Temperature - This point protects
the compressor from running with hot oil being
injected into the screw housing, and is activated
by a direct reading from the RTD located in the oil
injection line.
7. Low Suction Pressure - This point protects the
compressor from drawing low suction pressure and
is activated by a direct reading from the suction pressure transducer, which reads the pressure from a tap
located in the suction stop/check valve housing.
8. High Discharge Pressure - This point protects the
compressor from developing high discharge pressure and is activated by a direct reading from the
discharge pressure transducer, which reads the
pressure from a tap located in the oil separator. In
addition to this alarm and shutdown, the compressor
package is ultimately protected from damage due to
over pressurization by at least one discharge pressure
relief valve located on the oil separator. The purpose
of this safety setpoint is to allow for a lower setpoint
to conform to a process requirement, and to prevent
the relief valve from opening.
9. Prelube Oil Pressure - This point acts as a permissive
to start the compressor, and protects against the
compressor starting with no oil lubrication. If, during
a start sequence, the prelube oil pressure fails to rise
above 4.0 PSID, the compressor will fail to start. The
prelube oil pressure is a calculated value obtained
by subtracting the discharge pressure reading from
the oil manifold pressure (oil filter outlet pressure)
reading.
10. Low Oil Pressure - This point protects the compressor from running with insufficient lubrication
pressure, and becomes active after a predetermined
period of running, usually sixty seconds. The oil pressure is a calculated value obtained by subtracting the
suction pressure from the oil manifold pressure (oil
filter outlet pressure) reading, which results in the
actual pressure under which the oil is entering the
screw housing.
11. High Running Oil Filter Differential Pressure - This
point alerts operators to clogging oil filters. When
the oil filters develop a high differential pressure
while running at normal operating temperatures,
it is an indication that they are becoming dirty and
must be changed. An alarm initially warns of dirty
filters; if the situation worsens before the filters are
changed a shutdown will stop the compressor.
In most cases, the safety setpoints described above
will have settings which are dictated by process
requirements, and not necessarily mechanical constraints of the compressor. Process pressures and
temperatures may vary considerably depending
on the application of the compressor, and the VSG
compressor is designed to work well in a broad range
of applications.. For this reason, it is impractical
to suggest “initial” setpoints to fit all applications.
Instead, minimum and maximum values for each
safety setpoint are provided, while precise settings
for the safety setpoints must be derived for each
installation.
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VSG Package Requirements
Process Gas Circuit
1. Suction Gas Stop/Check Valve - The VSG com-
pressor requires a manually operated stop valve on the
suction line to the compressor to allow for isolating the
compressor package from process gas. Also, a check valve
is required in the suction line to limit reverse rotation of
the compressor on shutdown.
2. Suction Line Strainer - Vilter strongly recommends the use of an inline suction gas strainer to protect
the VSG compressor from foreign material which may
enter the compressor with the suction gas. This strainer
is generally of stainless steel mesh construction. Vilter can
provide assistance in designing a strainer housing specifically suited to VSG applications.
3. Process Gas/Oil Separator - A separator vessel
capable of removing the oil from the discharge gas stream
with an efficiency down to at least 5 PPM oil carryover is
required. Vilter’s own available horizontal separator is an
ASME-coded vessel which uses five stages of separation to
achieve an oil loss of as little as 3 to 4 PPM.
4. Discharge Gas Relief Valve - To protect the compressor package from damage due to over pressurization,
a relief valve must be installed inside of any discharge line
hand block valves. The relief valve must be set to open at
a pressure lower than the Maximum Allowable Working
Pressure (MAWP) of the separator.
5. Oil Prelube Pump - Usually a direct driven gear
type pump, the oil pump is required to prelube the compressor prior to starting and to maintain oil pressure during any
periods of low compression ratio operation.
6. Oil Cooler/ Temperature Control Valve - An oil
cooler, either air or water cooled, must be used to remove
the heat of compression from the oil stream. A temperature control valve is used to maintain constant oil injection
temperature to the compressor.
7. Oil Filtration - Large capacity micronic oil filters
are required to filter the oil before injection into the VSG
compressor. Filtration down to 25 microns nominal or less
is generally acceptable. Dual filters are recommended to
allow replacement of one cartridge while the compressor
continues running with the other cartridge in service.
8. Oil Heater - An oil heater is generally required
and must be sized to maintain oil temperature of at least
90°F when the compressor is not running. For outdoor installations, low ambient temperatures and winds must be
considered when sizing the oil heater. Also, insulating the
separator and oil piping may be required in low temperature
ambient conditions.
Note - Because the oil system on the VSG compressor utilizes discharge gas pressure as the means to move the
injection oil through the system, it must be remembered that all components of the oil system are exposed to full discharge
pressure and must be pressure rated accordingly.
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Description
COMPRESSOR
The Vilter Single Screw Compressor is a positive
displacement, capacity and volume controlled,
oil flooded, rotary compressor which uses a
single main screw intermeshed by two opposing gate rotors. Gas compression occurs when
the individual teeth of each gate rotor sweep
through the grooves, or flutes, of the main screw
as the screw rotates. Compression occurs from
the time the screw flute is first closed off by the
gate rotor finger, until the time when the screw
flute has rotated to the point of lining up with
the discharge port in the compressor housing.
A labyrinth type seal is used to prevent gas at
discharge pressure from leaking past the end
of the screw. Any discharge gas leakage past
the labyrinth seal is vented back to suction via
four longitudinal holes drilled through the body
of the screw.
By venting the discharge end of the main screw
back to suction, forces on each end of the screw
are equal. This results in zero net axial forces on
the main bearings. With twin opposing gate
rotors, all radial forces are cancelled out also.
Main shaft bearings have no net forces except
the weight of the screw and the shaft assembly.
The suction gas enters the compressor housing
through the top inlet flange, at the driven end of
the unit. The driven end of the compressor housing is flooded with gas at suction pressure. The
gas enters the open end of the main screw flutes
at the driven end, and becomes trapped in the
screw flute as the screw rotates and the gate rotor
tooth enters the end of the flute. At this point, the
compression process begins. Directly after the
screw flute is closed off by the gate rotor tooth,
oil is injected into the groove.
The oil enters the compressor through a connection at the top of the compressor. The purpose of
the injected oil is to absorb the heat of compression, to seal the gate rotor tooth in the groove,
and to lubricate the moving parts.
Additional internal oiling ports are provided at the
main and gate rotor bearings to cool and lubricate
the bearings. The mechanical shaft seal housing
also contains oiling ports to lubricate, cool and
provide a sealing film of oil for the mechanical
shafts seal. Excess oil flows through the check
valves on the sealing baffle plate. This oil is directed at the main rotor roller bearing, which cools
and lubricates the front roller bearing.
The VSG compressors are comprised of three
rotating assemblies: the main screw assembly
and the two gate rotor assemblies. Each of these
rotating assemblies use a common bearing
configuration consisting of a single, cylindrical
rolling element bearing at one end, and a pair
of angular contact ball bearings at the other
end. The pair of angular contact ball bearings
are used to axially fix one end of the rotating
shafts, and to absorb the small amount of thrust
loads on the shafts. The inner races of the ball
bearings are securely clamped to the rotating
shafts, while the outer races are securely held
in the bearing housing, thus fixing the axial
position of the shaft in relation to the bearing
housings. The cylindrical roller bearings at the
opposite end of the shafts allow for axial growth
of the shafts while supporting the radial loads
from the shafts.
As the main screw rotates, the gate rotor is also
driven, causing the gate rotor tooth to sweep the
groove in the main screw. This sweeping action
reduces the volume of the groove ahead of the
gate rotor tooth and causes the trapped gas and
oil to be compressed in the reduced volume. As
the main screw continues to rotate, the gate rotor
tooth continues to reduce the groove volume to a
minimum, thus compressing the trapped gas to a
maximum pressure. A labyrinth seal arrangement
prevents the compressed gas from leaking past the
end of the screw. As the gate rotor tooth reaches
the end of the groove, the groove rotates to a
position that lines up with the discharge port in
the compressor housing and the gas/oil mixture is
discharged from the screw at high pressure. This
completes the compression cycle for a single flute
of the main screw.
Once the gas is swept from the main screw flute
through the discharge port, it passes into the
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Description
discharge manifold of the compressor. From
the discharge manifold, the gas/oil exits the
compressor housing
The Vilter VSG compressors feature the
exclusive Parallex™ Slide System, which
consists of a pair of slides for each gate rotor
assembly. These two independently operated slides are referred to as the capacity
slide and the volume ratio slide. On the
suction end of the screw, the capacity slide
moves to vary the timing of the beginning
of the compression process. With the
slide moved all the way out to the suction
end of the screw (the 100% position), the
compression process begins immediately
after the gate rotor tooth enters the screw
flute and closes off the end of the groove.
In this situation, the maximum volume of
gas is trapped in the screw flute at the start
of the compression process. As the slide
is pulled back away from the suction end
of the screw, the start of the compression
process is delayed as some of the suction
gas is allowed to spill back out of the screw
flute until the screw rotates far enough to
pass the end of the capacity slide and begin
compressing. This causes a reduced volume
of gas to be trapped in the screw flute when
the compression process begins. In this way,
the capacity of the compressor is reduced
from 100% down to as low as 10% of the full
rated capacity.
The capacity slide provides the means for
controlling specific process set points.
By continuously adjusting the flow of gas
through the compressor, either suction or
discharge pressure in a particular process
can be controlled. When coupled with a
microprocessor controller, the adjustable
capacity slide allows for precise and continuous automatic control of any parameter in
the process to a chosen set point.
the point of discharge to the downstream
process requirements. The volume ratio slide
operates at the discharge end of the screw,
and acts to vary the position of the discharge
port. When the slide is extended fully to the
discharge end of the screw (the 100% position), the compression process within the
screw flute continues until the screw rotates
far enough for the flute to pass the end of the
volume ratio slide. At this point, the screw
flute lines up with the discharge port and the
compressed gas is expelled from the screw
flute. As the volume ratio slide is pulled back
away from the discharge end of the screw,
the position of the discharge port is changed
and the gas is allowed to escape the screw
flute earlier in the compression process, at a
reduced pressure.
The overall volume ratio within the compressor is determined by the distance between
the front of the capacity slide (the start of
compression) and the back of the volume
ratio slide (the completion of compression).
Therefore, the volume ratio slide must
respond to changes in the downstream
pressure measured in the oil separator and
position itself for the required compression
ratio based on the position of the capacity
slide. By only compressing the gas within
the screw as far as required to match the
pressure in th e down stream receiver,
the compressor efficiency is maximized.
Proper positioning of the volume ratio slide
prevents either over compressing or under
compressing of the gas within the screw
flute. This allows the single screw compressor to efficiently handle a range of volume
ratios from as low as 1.2 up to 7.0.
The second slide for each gate rotor is the
volume ratio slide. The purpose of the
volume ratio slide is to maximize the efficiency of the compressor by matching
the gas pressure within the screw flute at
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Description
DESCRIPTION OF GAS SYSTEM FOR A STANDARD
COMPRESSOR SET
The gas passes through a stop valve and a check
valve and then through a mesh strainer mounted
directly to the inlet flange. The check valve is necessary to prevent reverse rotation and potential
damage or oil loss at shut down. The suction gas
enters the compressor housing through the top inlet
flange, at the driven end of the unit.
After compression the gas is discharged from the
discharge manifold directly into a oil separator tank.
On the discharge of the oil separator tank another
check valve is positioned to prevent the entry of
gas or liquid refrigerant in to the separator when
the compressor is shut down. The separator should
be allowed to equalize slowly to suction pressure
through a small bypass line around the suction check
or combination stop/check valve. This will allow the
compressor to start without a pressure differential
across it, reducing the starting power requirements.
From the discharge manifold, the gas/oil exits the
compressor housing and passes into the oil separator through a pipe elbow. The separator vessel
serves to separate the oil from the gas as the gas
stream moves from one end of the separator to
the other. The majority of the oil is separated from
the gas in the primary chamber of the vessel due to
changes in direction and velocity reduction. Any remaining oil mist is separated from the gas stream as
the stream passes through the coalescing elements
and into the secondary chamber of the vessel. The
gas at discharge pressure then exits at the far end
of the separator.
DESCRIPTION OF OIL SYSTEM FOR A STANDARD
COMPRESSOR SET
At start oil at is drawn from the oil separator tank by the
oil pump, and passes through a oil cooler and micronic
filters to the oil supply inlet on the compressor frame.
From there it internally lubricates all points internal to
the compressor. After start-up when the compressor
develops sufficient differential pressure the oil pump
can be shut down and the oiling can take place without
the use of the oil pump. On units with low pressure differentials such as booster and low pressure differential
high stage compressors, the oil pump must remain on
whenever the unit is running to maintain sufficient oil
flow.
Oil collected in the bottom of the separator is
drained off to be recirculated in the oil injection
system. The injection oil temperature is controlled
by several means the first of which is a three-way
mixing valve, which mixes hot oil directly from the
separator with oil which has passed through the
oil cooler to obtain oil at the desired temperature.
This oil then passes through a filter to remove any
contaminants, which may have been picked up
from the process gas, and is injected back into the
compressor.
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Installation
PIPING
Before installing piping, the compressor inlet and
outlet ports should be inspected to ensure no dirt
is present.
Piping should be supported so that no piping loads
are transmitted to the compressor casings.
All piping should be inspected for cleanliness before
installation. As each pipe is connected to the compressor, the coupling alignment should be checked
to ensure that no alteration has taken place.
If alignment has altered, the compressor is being
strained and the piping supports must be adjusted.
It is not sufficient merely to re-align the drive coupling, as this will not correct the cause of the strain.
Compressors must have an inlet strainer permanently fitted to the compressor inlet.
Care must be taken to avoid trapping the lines except for specific purposes. When traps are used, the
horizontal dimensions should be as short as possible
to avoid excessive oil trapping.
Steel pipe is generally used in large installations
when joints are welded.
For halocarbon piping, only wrought copper fittings should be used. Cast fittings as used for water
service are porous and will allow the refrigerant to
escape. Note this exception: In larger pipe sizes,
wrought fittings are not available. However, specially tested cast fittings are available and these may
be used with complete safety.
It is important to avoid short, rigid pipe lines that do
not allow any degree of flexibility. This must be done
to prevent vibration being transmitted through the
pipe lines to the buildings. One method of providing the needed flexibility to absorb the vibration is
to provide long lines that are broken by 90° Ells in
three directions.
A second method would be to install flexible pipe
couplings as close to the compressor unit as possible
with connections run in two different directions,
90° apart. These flexible connections should be
installed on both the high and low side lines of the
compressor unit.
Hangers and supports for coils and pipe lines should
receive careful attention. During prolonged operation of the coils, they may become coated with
ice and frost, adding extra weight to the coil. The
hangers must have ample strength and be securely
anchored to withstand the vibration from the compressor and adequately support the pipe lines.
In making up joints for steel pipe, the following
procedures should be followed:
For threaded connections, all threads on the pipe
and fitting should be carefully cleaned to remove
all traces of grease or oil. Threads should then be
wiped dry with a lintless cloth. Only thread filling
compounds suitable for service should be used for
making steel pipe joints. These compounds should
be used sparingly, and on the pipe only. Do not put
any on the first two threads to prevent any of the
thread sealing compound from entering the piping
system. Acetylene or arc welding is frequently used
in making steel pipe joints, however, only a skilled
welder should attempt this kind of work. Take care
to see no foreign materials are left in the pipes and
remove all burrs formed when cutting pipe.
16
This information is taken from and ANSI B31.3. The
installing contractor should be thoroughly familiar
with these codes, as well as any local codes.
Page 17
Installation
TESTING SYSTEM
FOR LEAKS
Vilter equipment is tested for leaks at the factory.
One the most important steps in putting the system
into operation is field testing for leaks. This must
be done to assure a tight system that will operate
without any appreciable loss of gas.
First, if test pressures exceed the settings of the
system, relief valves or safety devices, they must
be removed and the connection plugged during the
test. Secondly, all valves should be opened except
those leading to the atmosphere. Then, open all
solenoids and pressure regulators by the manual
lifting stems. All bypass arrangements must also
be opened.
HYDROCARBON SYSTEMS
OIL FOR SINGLE SCREW
COMPRESSORS
Due to the need for adequate lubrication, Vilter recommends only the use of Vilter lubricants, designed
specifically for Vilter compressors. With the extensive
research that has been performed, we are able to offer specific lubricating oils. Use of oil not specified or
supplied by Vilter will void the compressor warranty.
“Oil pumped” dry nitrogen, or anhydrous CO2 in
this order of preference may be used to raise the
pressure to the proper level for testing.
When the proper pressure is attained, test for leaks
with the soap mixture previously described. After
all leaks are found and marked, relieve the system
pressure and repair the leaks. Never attempt to
repair soldered or welded joints while the system is
under pressure. Soldered joints should be opened
and re soldered.
Do not simply add more solder to the leaking
joint. After all the joints have been repaired and the
system is considered “tight”.
Remove the drum and bring the pressure to the recommended test level with oil pumped dry nitrogen
or CO2. Then check the entire system again for leaks,
using a halide torch or electronic leak detector.
Be sure to check all flanged, welded, screwed and
soldered joints, all gasketed joints, and all parting
lines on castings. If any leaks are found, they must
be repaired and rechecked before the system can be
considered tight again, remembering that no repair
should be made to welded or soldered joins while
the system is under pressure.
17
Page 18
Installation & Calibration of Slide Valve Actuators
Slide Valve Actuator Installation Instructions
Caution
WHEN INSTALLING THE OPTICAL SLIDE MOTOR,
LOOSEN LOCKING COLLAR BEFORE SLIDING THE
COLLAR DOWN ON THE SHAFT. DO NOT USE A
SCREWDRIVER TO PRY LOCKING COLLAR INTO
POSITION.
OVERVIEW
Calibration of an optical slide valve actuator is a two
step process that must be done for each actuator
installed of the compressor. Briey, the steps are as
follows.
1) The actuator motor control module, located
inside the actuator housing, is calibrated so
that it knows the minimum and maximum rotational positions of the slide valve it controls.
The calibrated actuator will output 0 VDC at the
minimum position and 5 VDC at the maximum
position.
2) After the actuator motor control module has been
calibrated for 0-5Volts, the controlling channel
corresponding to the actuator motor (either the
capacity or volume) has to be calibrated. This
instructs the control panel to learn the rotational
0% position & rotational 100% position of the slide
valve travel.
PLEASE NOTE:
Because there is an optical sensor on this motor, do
not attempt calibration in direct sunlight.
ACTUATOR MOTOR CONTROL
MODULE CALIBRATION PROCEDURE
1. Disable the Slide Non-Movement Alarm by going to the “Setup” menu on the control panel
and choosing “Alarm Disable” for the Slide NonMovement Option. (If applicable).
2. Completely shut off the power to the control
panel completely.
3. If not already done, mount the slide valve actuator per (“Vilter Actuator set up for Capacity and
Volume Slide Motors). Next, wire the actuator
per the attached wiring diagrams, using the
already installed electrical conduit to run the
cables. The old wiring can be used to pull the
new cables through the conduit to the control panel. The cables may also be externally
tie-wrapped to the conduit. Run the yellow
AC power cable(s) and the gray DC position
transmitter cable(s) in different conduit. This
prevents the DC position transmitter cable from
picking up electrical noise from the AC power
cable. Do not connect either of the cables to
the actuators yet.
In addition, if the actuators are replacing old gearmotors on early units, you must remove the capaci-
tors and associated wiring from inside the control
panel. This is necessary to prevent electrical damage
to the new actuator motor.
4. When completing the calibration of the new
actuators, the motors are signaled to move
to below 5%. This may not completely occur
when exiting the calibration screen due to a
“program timer”. HOWEVER, when the compressor actually starts, the motors will travel
below 5% and function correctly. The user may
see that the actuators are not below 5% after
calibration and try to nd the reason. If the
calibration screen is re-entered right away and
then exited, the timer will allow the actuator
to go below the 5% on the screen. This may
be perceived as a problem; in reality,it is not.
5. Note:The 0 to 5V-position transmitter
output of the actuator will uctuate wildly
during the calibration process. To prevent
damage to the actuators, do not connect the
yellow power cable or the gray position
transmitter cable until instructed to do so
later on.
6. Open the plastic cover of the capacity motor by
removing the four #10 screws.
18
Page 19
Installation & Calibration of Slide Valve Actuators
Caution: there are wires attached to the connector o n the plastic cover. Handling the
cover too aggressively could break the wires.
7. Gently lift the cover and tilt it toward the Turck
connectors. Raise the cover enough to be able
to press the blue calibrate button and be able
to see the red LED on the top of assembly.
8. Press “Menu” on the main screen and then press
the “Slide Calibration” button, to enter the slide
calibration screen. (Note: you must be in this slide
calibration screen before attaching the yellow
power cable or gray position transmitter cable.)
9. Now connect the yellow power cable and the
gray position transmitter cable to the actuator.
10. Press INC and DEC to move the slide valve and check
for the correct rotation. See Table 1on page 48 for
Actuator/command shaft rotation specications.
11. Note: If the increase and decrease buttons do
not correspond to increase or decrease shaft
rotation, swap the blue and brown wires of
the “yellow power cable”. This will reverse
the rotation of the actuator/command shaft.
12. Quickly press and release the blue push button on the actuator one time. This places the actuator in calibration mode. The
r e d LE D wi ll b eg in f la sh in g r ap id ly.
13. Note: When the actuator is in calibration
mode, it outputs 0V when the actuator is running
and 5V when it is still. Thus, as stated earlier, the
actuator voltage will uctuate during calibration. After the actuator has been calibrated,
0V output will correspond to the minimum
position and 5V to the maximum position.
15. Use the DEC button on the control panel to
drive the slide valve to its minimum “mechanical stop” position. Do not continue to run the
actuator in this direction after the slide valve
has reached the stop. Doing so may cause damage to the actuator or the slide valve. When
the slide has reached the mechanical stop position, use the INC button to pulse the actuator
to where the slide is just off of the mechanical
stop and there is no tension on the motor shaft.
16. Quickly press and release the blue button on
the actuator again. The red LED will now ash
at a slower rate, indication that the minimum
slide valve position (0V position) has been set.
17. Use the INC button on the control panel to drive
the slide to its maximum “mechanical stop” position. Do not continue to run the actuator in this
direction after the slide valve has reached the
stop. Doing so may cause damage to the actuator or the slide valve. When the slide valve has
reached the mechanical stop position, use the
DEC button to pulse the actuator to where the
slide is just off of its mechanical stop and there
is no tension on the motor shaft.
18. Quickly press and release the blue button on the
actuator one more time. The red LED will stop
ashing. The actuator is now calibrated and knows
the minimum and maximum positions of the slide
valve it controls. Now the capacity or volume
channel of the control panel can be calibrated.
19. Use the Dec button to move the actuator towards
its minimum position while watching the millivolt readout on the control panel screen. Discontinue pressing the DEC button when the millivolt
reading in the “Current” window above the “Set
Min” button is approximately 500 millivolts.
14. Note: The “Slide calibration” screen on the control panel has a “Current” window, which displays
twice the actuator output voltage. This value,
(the % volume and the % capacity) displayed in
the “Current Vol” and Current Cap” Windows are
meaningless until calibration has been completed.
20. Now use the DEC and INC buttons to position the
slide valve until a value close to 300 millivolts is on
the screen. Then, press the “Set Min” button for
the capacity or volume slide valve window to tell
the controller that this is the minimum millivolt
position. Note: The value in the “Current Cap” or
“Current Vol” window has no meaning right now.
19
Page 20
Installation & Calibration of Slide Valve Actuators
21. Use the INC button to rotate the actuator towards its maximum position while watching
the millivolt readout on the controller screen.
Discontinue pressing the INC button when
the millivolt reading in the “Current” window
is approximately 9200 millivolts (7900 mil-
livolts for the 2783J qualied analog boards).
You are nearing the mechanical stop position.
22. Pulse the INC button to carefully move the slide
valve until the millivolt readout “saturates”, or
stops increasing. This is around 9500 millivolts
(8400 millivolts for 2783 qualied analog boards).
23. Pulse the DEC button until the millivolts just
start to decrease. (This is the point where
the channel drops out of saturation).Adjust millivolt value to 300 millivolts below
recorded maximum millivolts in step #22.
24. Press the “Set Max” button.
25. Press the “Main” button to complete calibration and exit the “Slide Calibration” screen.
The controller will automatically energize
the actuator and drive it back to its minimum position (below 5%) for pre-start-up.
26. Note: Now the “Current Cap” or the “Current
Vol” value will be displayed in the window on the
“Main” screen and the “Slide Calibration” screen.
27. Gently lower the plastic cover over the top
of the actuator to where it contacts the base
and o-ring seal. After making sure the cover
is seated properly, gently tighten the four
#10 screws. Caution: The plastic cover
will crack if the screws are over tightened.
28. Enable the “Slide Non-Movement Alarm” by going to the “Setup” menu and choosing “Alarm
Enable” for the “Slide Non-Movement Option”.
29. This completes the calibration for this channel either capacity or volume. Repeat the
same p rocedure to the other chan n el .
20
Page 21
Slide Valve Operation
Slide Valve Actuator Operation
The slide valve actuator is a gear-motor with a position sensor. The motor is powered in the forward
and reverse directions from the main computer in
the control panel. The position sensor tells the main
computer the position of the slide valve. The main
computer uses the position and process information
to decide where to move the slide valve next.
The position sensors works by optically counting motor turns. On the shaft of the motor is a small aluminum “photochopper”. It has a 180 degree fence that
passes through the slots of two slotted optocouplers.
The optocouplers have an infrared light emitting diode (LED) on one side of the slot and a phototransistor
on the other. The phototransistor behaves as a light
controlled switch. When the photochopper fence
is blocking the slot, light from the LED is prevented
from reaching the phototransistor and the switch is
open. When photochopper fence is not blocking the
slot, the switch is closed.
This scheme is not foolproof. If the motor is moved
manually while the power is off or the motor brake
has failed, allowing the motor to free wheel for too
long after the position sensor looses power, the actuator will become lost.
A brake failure can sometimes be detected by the
position sensor. If the motor never stops turning after
a power loss, the position sensor detects this, knows
it will be lost, and goes immediately into calibrate
mode when power is restored.
As the motor turns, the photochopper fence alternately blocks and opens the optocoupler slots,
generating a sequence that the position sensor microcontroller can use to determine motor position by
counting. Because the motor is connected to the slide
valve by gears, knowing the motor position means
knowing the slide valve position.
During calibration, the position sensor records the
high and low count of motor turns. The operator tells
the position sensor when the actuator is at the high
or low position with the push button. Refer to the
calibration instructions for the detailed calibration
procedure.
The position sensor can get “lost” if the motor is
moved while the position sensor is not powered. To
prevent this, the motor can only be moved electrically
while the position sensor is powered. When the position sensor loses power, power is cut to the motor. A
capacitor stores enough energy to keep the position
sensor circuitry alive long enough for the motor to
come to a complete stop and then save the motor
position to non-volatile EEPROM memory. When
power is restored, the saved motor position is read
from EEPROM memory and the actuators resumes
normal function
21
Page 22
Slide Valve Actuator Trouble Shooting Guide
Problem Reason Solution
The actuator cannot be calibrated
Dirt or debris is blocking one or
both optocoupler slots
The photochopper fence extends
less than about half way into the
optocoupler slots
The white calibrate wire in the grey
Turck cable is grounded
Dirt and/or condensation on the
position sensor boards are causing
it to malfunction
Clean the optocoupler slots
with a Q-Tip and rubbing alcohol.
Adjust the photochopper so
that the fence extends further
into the optocoupler slots.
Make sure the motor brake
operates freely and the photochopper will not contact the
optocouplers when the shaft is
pressed down.
Tape the end of the white wire
in the panel and make sure that
it cannot touch metal
Clean the boards with an electronics cleaner or compressed
air.
The actuator goes into calibration mode spontaneously
The actuator goes into calibration mode every time
power is restored after a
power loss
The calibr ate button is stuck
down
The position sensor has failed
Push button is being held down for
more that ¾ second when going
through the calibration procedure
The white calibrate wire in the grey
Turck cable is grounding intermittently
A very strong source of electromagnetic interference (EMI), such as a
contactor, is in the vicinity of the
actuator or grey cable
There is an intermittent failure of
the position sensor
The motor brake is not working properly (see theory section
above.)
Try to free the stuck button.
Replace the actuator.
Depress the button quickly and
then let go. Each ¾ second the
button is held down counts as
another press.
Tape the end of the white wire
in the panel and make sure that
it cannot touch metal.
Increase the distance between
the EMI source and the actuator.
Install additional metal shielding material between the EMI
source and the actuator or
cable.
Replace the actuator.
Get the motor brake to where it
operates freely and recalibrate.
22
Page 23
Slide Valve Actuator Trouble Shooting Guide
Problem Reason Solution
The actuator does not transmit the correct position after
a power loss
There is a rapid clicking noise
when the motor is operating
The motor operates in one
direction only
The motor was manually moved
while the position sensor was not
powered.
The motor brake is not working
properly
The position sensor’s EEPROM
memory has failed
The photochopper is misaligned
with the slotted optocouplers
The photochopper is positioned
too low on the motor shaft.
A motor bearing has failed
There is a loose connection in the
screw terminal blocks
There is a loose or dirty connection in the yellow Turck cable
The position sensor has failed
Recalibrate.
Get the motor brake to where it
operates freely and then recalibrate.
Replace the actuator.
Try to realign or replace the actuator.
Adjust the photochopper so that
the fence extends further into
the optocoupler slots.
Replace the actuator.
Tighten.
Clean and tighten.
Replace the actuator.
The motor will not move in
either direction
The motor runs intermittently,
several minutes on, several
minutes off
There is a broken motor lead or
winding
The thermal switch has tripped
because the motor is overheated
Any of the reasons listed in “The
motor operates in one direction
only”
The command shaft is jammed
Broken gears in the gearmotor
Motor is overheating and the
thermal switch is tripping
Replace the actuator.
The motor will resume operation when it cools. This could be
caused by a malfunctioning control panel. Consult the factory.
See above.
Free the command shaft.
Replace the actuator.
This could be caused by a malfunctioning control panel. Consult the factory.
23
Page 24
Slide Valve Actuator Trouble Shooting Guide
Problem Reason Solution
The motor runs sporadically
Bad thermal switch
Any of the reasons listed in “The
motor will not move in either direction”
The motor runs but output
shaft will not turn
Slide Valve Actuators communicate problems discovered by internal diagnostics via LED blink codes. Only one blink
code is displayed, even though it is possible that more than one problem has been detected.
Flash Pattern Meaning
*=ON
_=OFF
*_*_*_*_*_*_*_*_*_*_*_ Calibration step 1
Stripped gears inside the gear motor or the armature has come unpressed from the armature shaft
Replace the actuator.
See above.
Replace the actuator.
*___*___*___*___*___ Calibration step 2
*__*________________ This indicates a zero span. This error can only occur during calibration. The typical
cause is forgetting to move the actuator when setting the upper limit of the span.
If this is the case, press the blue button to restart the calibration procedure. This
error can also occur if either or both of the slotted optocouplers are not working. If
this is the case, the slide valve actuator will have to be replaced.
The operation of the slotted optocouplers is tested as follows:
1. Manually rotate the motor shaft until the aluminum photochopper fence is not
blocking either of the optocoupler slots.
2. Using a digital multi-meter, measure the DC voltage between terminal 3 of
the small terminal block and TP1 on the circuit board (see Note 1). You should
measure between 0.1 and 0.2 Volts.
3. Next, measure the DC voltage between terminal 3 and TP2 on the circuit
board. You should measure between 0.1 and 0.2 Volts.
24
Page 25
Slide Valve Actuator Trouble Shooting Guide
*__________________ This indicates a skipped state in the patterns generated by the optocouplers as the
motor moves. This error means that the slide valve actuator is no longer transmitting accurate position information. The actuator should be recalibrated as soon as
possible. This code will not clear until the actuator is recalibrated.
This code can be caused by:
1. The motor speed exceeding the position sensors ability to measure it at some
time during operation. A non-functioning motor brake is usually to blame.
2. The actuator is being operated where strong infrared light can falsely trigger
the slotted optocouplers, such as direct sunlight. Shade the actuator when the
cover is off for service and calibration. Do not operate the actuator with the
cover off.
*__*__*____________ The motor has overheated. The actuator motor will not run until it cools. Once the
motor cools, the actuator will resume normal operation.
Motor overheating is sometimes a problem in hot and humid environments when
process conditions demand that the slide valve reposition often. Solutions are
available; consult your Vilter authorized distributor for details.
Another possible cause for this error is a stuck motor thermal switch. The thermal switch can be tested by measuring the DC voltage with a digital multi-meter
between the two TS1 wire pads (see Note 2). If the switch is closed (normal operation) you will measure 0 Volts.
******************** The 24V supply is voltage is low. This will occur momentarily when the actuator is
powered up and on power down.
If the problem persists, measure the voltage using a digital multi-meter between
terminals 3 and 4 of the small terminal block. If the voltage is >= 24V, replace the
actuator.
_******************* The EEPROM data is bad. This is usually caused by loss of 24V power before the
calibration procedure was completed. The actuator will not move while this error
code is displayed. To clear the error, calibrate the actuator. If this error has occurred and the cause was not the loss of 24V power during calibration, possible
causes are:
1. The EEPROM memory in the micro-controller is bad.
2. The large blue capacitor is bad or has a cracked lead.
*****____*__________ Micro-controller program failure. Replace the actuator.
Note 1: TP1 and TP2 are plated-thru holes located close to the slotted optocouplers on the board. They are clearly
marked on the board silkscreen legend.
Note 2: The TS1 wire pads are where the motor thermal switch leads solder into the circuit board. They are clearly
marked on the board silkscreen legend and are oriented at a 45 degree angle.
25
Page 26
Operation Section
Notice on using Non -Vilter Oils
Oil and its additives are crucial in system performance. Vilter Manufacturing will NOT APPROVE non-Vilter oils
for use with Vilter compressors. Due to the innumerable choices available it is not possible for us to test all oils
offered in the market place, and their effects on our equipment.
We realize that customers may choose lubricants other than Vilter branded oil. This is certainly within the
customers’ right as owners of the equipment. When this choice is made, however, Vilter is unable to accept
responsibility for any detrimental affects those lubricants may have on the equipment or system performance
and durability.
Should a lubrication related system issue occur with the use of non-Vilter oils, Vilter may deny warranty upon
evaluation of the issue. This includes any parts’ failure caused by inadequate lubrication.
Certainly, there are many good lubricants in the market place. The choice of a lubricant for a particular application involves consideration of many aspects of the lubricant and how it and its additive package will
react in the various parts of the entire system. It is a complex choice that depends on a combination of field
experience, lab and field-testing, and knowledge of lubricant chosen. Vilter will not accept those risks other
than for our own lubricants.
26
Page 27
Operation
CONTROL SYSTEM
A. Screw Compressor Control And Operation
1. Starting, Stopping and Restarting the Compressor.
Before the screw compressor unit may start, certain
conditions must be met. All of the safety setpoints
must be in a normal condition, and the suction pressure must be above the low suction pressure setpoint
to assure that a load is present. When the “On-Off”
switch or “Manual-Auto” button is pressed, the oil
pump will start. When sufficient oil pressure is built
up and the compressor capacity control and volume
ratio slide valves are at or below 10%, the compressor
unit will start.
If the compressor is in the automatic mode, it will
now load and unload and vary the volume ratio in
response to the system demands.
Stopping the compressor unit can be accomplished
a number of ways. Any of the safety setpoints will
stop the compressor unit if an abnormal operating
condition exists. The compressor unit “On-Off” or
stop button will turn the compressor unit off as will
the low pressure setpoint. If any of these conditions
turns the compressor unit off, the slide valve motors
will immediately energize to drive the slide valves
back to 5% limit. The control motors will be deenergized when the respective slide valve moves back
below 5%. If there is a power failure, the compressor
unit will stop. If the manual start on power failure
option is selected (see appropriate Microprocessor
Instruction Manual), restarting from this condition is
accomplished by pushing the reset button to insure
positive operator control. If the auto start on power
failure option is selected (see appropriate Microprocessor Instruction Manual), the compressor unit will
start up after a waiting period. With both options,
the compressor slide valves must return below their
respective 5% limits before the compressor unit can
be restarted.
2. Slide Valve Control Actuators
Note:
Optical Actuators CAN NOT
be manually rotated.
View Capacity
View Volume
Ratio
SLIDE VALVE ACTUATOR LOCATION:
VSG 401 CCW
When viewing the compressor from the discharge
end (opposite the drive end), the upper motor is
for capacity control. The command shaft turns (see
Table 1) to decrease the capacity to 10% and reverses
to increase the capacity to 100%. The lower motor is
for volume ratio control. The command shaft turns
(see Table 1) to reduce the volume ratio to 2.0, and
reverses to increase the volume ratio to 5.0.
Actuation of the electric motors can be done manually or automatically. To actuate the motors manually, place the desired mode selector in the manual
position and push the manual Increase or Decrease
buttons. In the automatic mode, the microprocessor determines the direction to actuate the electric
motors. However, in the automatic mode, there is an
“On” and “Off” time for the capacity control motor.
The “On” time is the time in which the slide valve
moves, and the “Off” time is the time in which the
system is allowed to stabilize before another change
in slide valve position.
View Capacity
View Volume
Ratio
Capacity and volume ratio control of the screw compressor is achieved by movement of the respective
slide valves, actuated by electric motors.
SLIDE VALVE ACTUATOR LOCATION:
VSG 501 CW Thru VSG 701 CW
27
Page 28
Operation
Table 1
COMMAND SHAFT ROTATION NO. OF TURNS / ROTATION ANGLE / SLIDE TRAVEL
COMP. CAPACITY VOLUME CAPACITY VOLUME
MODEL INC DEC INC DEC TURNS/DEGREES/TRAVEL TURNS/DEGREES/TRAVEL
VSSG 291 CW CCW CW CCW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSSG 341 CW CCW CW CCW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSSG 451 CW CCW CW CCW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSSG 601 CW CCW CW CCW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSG 751 CCW CW CCW CW 1.09 / 392 / 4.283” 0.63 / 227 / 2.473”
VSG 901 CCW CW CCW CW 1.09 / 392 / 4.283” 0.63 / 227 / 2.473”
VSG 1051 CCW CW CCW CW 1.22 / 439 / 4.777” 0.74 / 266 / 2.889”
VSG 1201 CCW CW CCW CW 1.22 / 439 / 4.777” 0.74 / 266 / 2.889”
VSG 1551 CCW CW CCW CW 1.36 / 490 / 5.325” 0.82 / 295 / 3.200”
VSG 1851 CCW CW CCW CW 1.36 / 490 / 5.325” 0.82 / 295 / 3.200”
VSG 2101 CCW CW CCW CW 1.36 / 490 / 5.325” 0.82 / 295 / 3.200”
VSG 301 CW CCW CW CCW 0.80 / 288 / 3.141” 0.45 / 162 / 1.767”
VSG 361 CW CCW CW CCW 0.80 / 288 / 3.141” 0.45 / 162 / 1.767”
VSG 401 CW CCW CW CCW 0.80 / 288 / 3.141” 0.45 / 162 / 1.767”
VSG 501 CCW CW CCW CW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSG 601 CCW CW CCW CW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
VSG 701 CCW CW CCW CW 0.91 / 328 / 3.568” 0.52 / 187 / 2.045”
NOTE: These refer to the old style gear motors and DO NOT apply to the new optical motors. Rotation for the
optical motors is the OPPOSITE of what is shown in the chart.
4. Oil Filter Differential
B. Safety Setpoints
High oil filter differential cutout stops the compresA detailed explanation of all safety setpoints can be found
in the Compact Logix PLC manual, p/n 35391CL.
1. Oil Pressure
Low oil pressure differential stops the compressor unit
when there is an insufficient difference in pressure
between the oil manifold and suction.
2. Discharge Pressure
High discharge pressure cutout stops the compressor
unit, when the discharge pressure in the oil separator
exceeds the setpoint.
3. Suction Pressure
Low suction pressure cutout stops the compressor
unit when the suction pressure drops below the
setpoint.
sor unit when the difference between the outlet and
inlet of the filter exceeds the setpoint.
5. Oil Temperature
The oil temperature cutout stops the compressor
unit when the oil temperature is too high or too low.
6. Discharge Temperature
The high discharge temperature cutout stops the
compressor unit when the discharge temperature
exceeds the setpoint.
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Maintenance
OR
Gas Compression Maintenance and Inspection Schedule
120,000
110,000
100,000
90,000
80,000
70,000
60,000
50,000
40,000
SERVICE INTERVAL (HOURS)
30,000
II
I II I I I
I I I II I
R R R R
I
BASED ON DRY CLEAN GAS
20,000
10,000
5,000
200
ITEM
MAINTENANCE
S S S S S S S S S S S S S
R R R R R R R
I I I I I I I I I I I I I I
R R R R R R R R R R R R R R
Oil Change
Oil Analysis (1)
Oil Filters
Oil Strainer
I I I I I I I I I I I I I I
Coalescing Elements
Coupling Alignment
Suction Screen
I I I I I I I I I I I I I I
Transducers
and Integrity
I I I I I I I
I I I I I I I I I I I I I I
RTD's
Key: (I) Inspect. (R) Replace. (S) Sample.
Inspect Compressor
Bearings
(2) Note: The life of the compressor will be increased by purging the compressor unit with dry nitrogen or sweet, dry natural gas at
(1) Note: Oil Analysis/Sampling is based on the gas stream. It is at the customer's discretion to increase the time period between oil
sampling if contamination of oil is unlikely, and to decrease the time period between oil sampling if oil contamination is likely or
evident. An oil sample must be taken when there is reason to believe the oil is contaminated anytime during operation. In landfill,
corrosive, and wet gas conditions, oil sampling is recommended every 3-4 months.
droplets of liquid at the compressor suction. The discharge temperature of the compressor must be kept a minimum of 30°F above
the discharge gas dew point to prevent the condensing of liquids in the oil separator. The oil separator shell and legs must be
The life of the oil is directly affected by the quality of the gas. Proper separation of any liquids must be accomplished to prevent
insulated when the gas stream has a high probability of having condensables.
shutdown.
NOTE: See Motor Manual for proper lubrication procedures and service intervals.
GROUP
CALIBRATION
OIL CIRCUIT
PACKAGE
COMPRESSOR (2)
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Service
GENERAL COMMENTS
When working on the compressor, care must be taken
to ensure that contaminants (i.e. water from melting
ice, dirt and dust) do not enter the compressor while
it is being serviced. It is essential that all dust, oil or
ice that has accumulated on the outside of the compressor be removed before servicing the compressor.
When servicing the compressor, all gaskets, O-rings,
roll pins and lock washers must be replaced when
reassembling the compressor.
PREPARATION OF UNIT FOR SERVICING
A) Shut down the unit, open the electrical discon-
nect switch and pull the fuses for the compressor
motor to prevent the unit from starting. Put a
lock on the disconnect switch and tag the switch
to indicate that maintenance is being performed.
B) Isolate the unit by manually closing the discharge
Stop valve. Allow the unit to equalize to suction
pressure before closing the Suction Bypass. After
the unit has equalized to suction pressure and
suction valve closed, use an acceptable means to
depressurize the unit that complies with all Local,
State and Federal Ordinances.
C) Remove drain plugs from the bottom of com-
pressor housing and the discharge manifold On
units equipped with Suction Oil Injection (SOI)
manually open the SOI solenoid valve below the
compressor. Drain the oil into appropriate containers.
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Service
Top View
Direction of rotor movement.
Axial force at coupling
to be 300-500lbs.
Rigidly attach dial indicator.
Position it on the axis of the
compressor.
Small wooden block or fulcrum.
Force to be determined
by length of level arm.
Rotor Being Pushed By
Use Of Lever
Top View
Direction of rotor movement.
Axial force at coupling
to be 300-500lbs.
Small wooden block
or fulcrum.
Force to be determined
by length of level arm.
Rotor Being Pushed in the
opposite direction by use of a lever.
Rigidly attach dial
indicator.
Position it on the
axis of the
compressor.
Direction of rotor movement.
Axial force at gate rotor to be
200 to 300 lbs.
Wooden block to prevent
damge to gate rotor blade.
Force to be determined
by length of level arm.
Use bolt for fulcrum.
Rigidly attach
dial indicator.
Side View
Showing gate rotor bearing float
being measured.
COMPRESSOR INSPECTION
The Vilter Single Screw Compressor is designed for
long periods of trouble free operation with a minimum of maintenance. However, a yearly inspection
is recommended so any irregular wear is noted and
rectied. At this time, the bearing oat is measured
for the main rotor and gate rotors.
The following are the procedures used in measuring
the main rotor and gate rotor bearing oat.
BEARING CHECK
When taking the measurements, do not exceed 300 to
500 Lbs. of force at point of contact or damage may
result to the bearings
CAUTION
A) Shut down and de-pressurize the unit.
B) Main rotor bearing oat.
1) Remove the coupling guard, then remove the
center member from the coupling.
2) Attach a dial indicator to the compressor
frame as shown and zero indicator. Place a
lever arm and fulcrum behind the compressor
coupling half and push the coupling towards
the motor (note measurement).
TABLE.1 MAXIMUM BEARING FLOAT
MAIN GATE
Bearing Float 0.003” 0.002”
Maximum Force 300 to 500 200 to 300
Lbs. Lbs.
3) Re-Zero indicator, now position the fulcrum
on the motor and use the lever arm to push
the input shaft towards the compressor (note
measurement).
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4) Add both readings, the total indicator move-
ment is the bearing oat and this should not
exceed 0.003”.
C) Gate rotor bearing oat.
1) Remove the side covers and position a dial
indicator on the gate rotor.
2) Use a lever arm pivoting on a bolt with a
small block of wood against the gate rotor
blade to protect the blade.
3) The maximum amount of bearing float
should not exceed 0.002”.
Service
TABLE 2. GATE ROTOR FLOAT
MODEL FLOAT
VSG 301 THRU 401 0.045”
VSG 501 THRU 701 0.045”
VSSG 291 THRU VSSG 601 0.045”
VSG 751 & VSG 901 0.055”
VSG 1051 & VSG 1201 0.060”
VSG 1551 THRU VSG 2101 0.060”
E) Readings could be higher than 0.020. If read-
ings is greater than 0.030 over table tolerance
contact Vilter’s home ofce.
F) Inspect the main and gate rotors for signs of ab-
normal wear due to dirt or other contaminants.
G) After the inspection is complete, the covers,
coupling center member and guard can be
reinstalled and the unit can then be evacuated
and leak checked before starting.
D) Measure the gate rotor to blade oat. Some
movement between blade and support is necessary to prevent damage to the compressor blade,
however at no time should the blade uncover the
support.
1) Position the blade with the gate rotor
damper pin and 90º to the main rotor.
2) Position a dial indicator at the tip of the support. The total movement of the damper pin
in the bushing is the gate rotor oat. Refer
to table 0.2 to nd the maximum blade to
support float (on new compressor parts
only).
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Service
GATE ROTOR ASSEMBLY CAUTION
Gate rotor removal and assembly is divided into distinct instructions, instructions for all VSG and VSSG
models and different instructions for all VSM models.
Please follow the appropriate set of instructions.
For VSG 451 thru 601
compressors, do not
use side rails.
For VSSG 751/901 & VSG 1051/1201
compressors, use side rails and
assemble to gaterotor stablizer
as stamped.
Drive End
90 1A
90 1B
90 1C
REMOVAL ( All VSG)
A) Prepare the compressor for servicing.
NOTE: All parts must be kept with their appro-
priate side and not mixed when the compressor is reassembled.
B) Remove two upper bolts from the side cover,
and install guide studs in the holes. Remove the
remaining bolts and side cover. There will be
some oil drainage when the cover is removed.
C) Turn the main rotor so a driving edge of any one
of the main rotor grooves is even with the back
of the gate rotor support.
D) Insert the gate rotor stabilizer. The side rails
are not required on VSSG 291 thru 601. For the
VSG 751 thru 901 and VSG 1051 thru 1201
compressors, use the side rails and assemble to
the gate rotor stabilizer as stamped. For the VSG
1551 thru 2101, use the side rails and assemble
to the gate rotor stabilizer.
The gate rotor stabilizer is designed to hold the
gate rotor support in place and prevent damage
to the gate rotor blade as the thrust bearings and
housing is being removed.
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Service
E) Remove the hex head and socket head bolts from
the thrust bearing cover. Insert two of the bolts
into the threaded jacking holes to assist in removing the cover. Retain the shim pack and keep it
with the bearing housing cover.
F) Hold the gate rotor support with a suitable wrench
on the ats provided near the roller bearing housing. Remove the inner retainer bolts and the
retainer. To remove the thrust bearing housing,
install the thrust bearing removal and installation
tool with the smaller puller shoe. Turn the jacking
screw clockwise. The thrust bearings and housing
assembly will be pulled off the shaft and out of the
frame.
G) Remove the bolts on the roller bearing housing.
Thread two bolts into the jack screw holes provided in the housing to assist in removing it.
H) To remove the gate rotor support, carefully move
the support opposite the direction of rotation and
tilt the roller bearing end towards the suction end
of the compressor. The compressor input shaft
may have to be turned to facilitate the removal of
the gate rotor support. On dual gate compressor
units, repeat the procedure for the remaining gate
rotor support assembly.
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Service
REMOVAL (ALL VSG 301-701 MODELS)
The removal of the gate rotor assembly for the VSG
301-701 compressors is similar for the VSG 9012101 compressors. The inner races are secured to
the stationary bearing spindle.
A) Prepare the compressor for servicing.
B) Remove the upper bolt from the side cover and
install a guide stud in the hole. Remove the
remaining bolts and side cover. There will be
some oil drainage when the cover is removed.
C) The side cover that contains the suction strainer
should have the suction line properly supported
before the bolts securing the line to the cover
can be removed. After the line is removed, the
cover can be removed per paragraph B.
D) Turn the main rotor so the driving edge of the
groove is between the top of the shelf or slightly
below the back of the gate rotor support. At
this point install the gate rotor stabilizing tool.
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Service
E) Remove plug on the thrust bearing housing.
Loosen the socket head cap screw that is located
underneath the plug. This secures the inner races
of the thrust bearings to the spindle.
F) Remove bolts that hold the thrust bearing hous-
ing to the compressor. Insert two of the bolts into
the threaded jacking holes to assist in removing
the bearing housing from the compressor. When
the housing is removed, there will be shims between the spindle and thrust bearings. These
control the clearance between the shelf and
gate rotor blades. These must be kept with their
respective parts for that side of the compressor.
G) Remove the bolts from the roller bearing housing.
After the bolts have been removed, the housing
can be removed from the compressor.
H) To remove the gate rotor support, carefully move
the support opposite the direction of rotation
and tilt the roller bearing end towards the suction end of the compressor. The compressor
input shaft may have to be turned to facilitate the
removal of the gate rotor support. On dual gate
versions, repeat the procedure for the remaining
gate rotor support assembly.
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Service
INSTALLATION (All VSG Models)
A) Install the gate rotor support by carefully tilting
B) Install the roller bearing housing (112) with a
C) When installing the thrust bearing housing
the roller bearing end of the gate rotor support
towards the suction end of the compressor. The
compressor input shaft may have to be rotated
to facilitate the installation of the gate rotor support.
Install gate rotor stabilizer. The gate rotor stabilizer (901) will hold the gate rotor support
in place as the thrust bearing housing is being
installed. If the gate rotor support is not restricted from moving, the gate rotor blade may
be damaged.
new O-ring (141). Tighten the bolts (152) to the
recommended torque value.
(113), a new O-ring (142) must be used when
the housing is installed. Lubricate the outside of
the housing and bearings with clean compressor
oil to aid in the installation. Due to the t of the
bearings on the gate rotor shaft, the thrust bearing removal and installation tool with the pusher
shoe must be used. Turn the jacking screw clockwise. This will push the thrust bearings onto the
shaft and push the housing assembly into the
frame. Install the inner retainer (115) and bolts
(151) using Loctite® 242 thread locker. Tighten
the bolts to the recommended torque value.
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Service
D) Set the clearance between the gate rotor blade
and the shelf.
1. Place a piece of 0.003”-0.004” shim stock
between the gate rotor blade and the shelf.
2. Measure the depth from the top of the compressor case to the top of the thrust bearing
housing. This determines the amount of
shims needed for the correct clearance.
3. Use factory installed shim pack (106) and
bearing housing cover (116) without the Oring (143). Check the clearance between the
entire gate rotor blade and the shelf, rotate
the gate rotor to nd the tightest spot. It
should be between 0.003”-0.004”. Make
adjustments, if necessary. It is preferable to
shim the gate rotor blade looser rather than
tighter against the shelf.
Note: Replacement blades are precisely the same
dimensionally as blades installed originally at factory: Therefore, the same amount of shims will be
required for replacement blades.
E) After clearance has been set install a new O-ring
(143) on bearing housing cover, install cover and
tighten the bolts to the recommended torque
value.
F) Install side cover with a new gasket. Tighten the
bolts to the recommended torque value. The
unit can then be evacuated and leak checked as
outlined in section 0.03.
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Gaterotor for C-ange Models
Service
INSTALLATION (All VSG 301-701 Models)
A) Install the gate rotor support. Carefully tilt the
roller bearing end of the gate rotor support towards the suction end of the compressor. The
compressor input shaft may have to be rotated
to facilitate the installation of the gate rotor
support.
B) Install the roller bearing housing with a new
O-ring. Tighten the bolts to the recommended
torque value.
C) Install the spindle with shims and o-ring, tighten
the bolts to the recommended torque value,
measure the clearance between the shelf and
blade.
D) Check the clearance between the entire gate
rotor blade and the shelf, rotate the gate rotor
to nd the tightest spot. It should be between
0.003”-0.004”. Make adjustments, if necessary.
It is preferable to shim the gate rotor blade
looser rather than tighter against the shelf.
E) Once the clearance is set remove the spindle.
Install new o-ring, apply Loctite 242 thread
locker to the socket head cap screw clamping
the thrust bearings to the spindle. Torque all
bolts to the recommended torque values.
F) Install side covers with new gaskets. Tighten
bolts to the recommended torque value. The
unit can now be evacuated and leak checked as
outlined in section 0.03.
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Service
GATE ROTOR BLADE REMOVAL
A) Remove the gate rotor assembly.
B) Remove the snap ring and washer from the gate
rotor assembly. Lift gate rotor blade assembly off
the gate rotor support.
C) Check damper pin and bushing for excessive wear.
Replace if necessary.
TOP of assembly
Relief area faces TOP of assembly.
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(with Relief)
Service
GATE ROTOR BLADE INSTALLATION
A) Install damper pin bushing (120) in gate rotor
blade (111) from the back side of the blade. Be
sure the bushing is fully seated.
B) Place the blade assembly on the gate rotor sup-
port. Locating Damper over pin.
C) Install washer (119) and snap ring (130) on gate
rotor assembly. The bevel on the snap ring must
face away from the gate rotor blade. After the
gate rotor blade and support are assembled,
there should be a small amount of rotational
movement between the gate rotor and support.
D) For installation of the gate rotor assembly and
setting of gate rotor clearance, refer to section
INSTALLATION (All VSG 301-701 Models).
GATE ROTOR THRUST BEARING REMOVAL
A) Refer to section INSTALLATION (All VSG Models)
for removal of the gate rotor bearing housings
and gate rotor supports.
B) For removal of thrust bearings on VSG units:
1) Remove bolts (150) from the clamping ring
(114).
2) Remove thrust bearing clamping ring.
3) Remove thrust bearings (126) from housing
(113).
C) For removal of thrust bearings on VSSG units:
1) Remove retaining ring from gate rotor support.
2) Remove bearings from support.
3) Remove bearing retainer from inner race.
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GATE ROTOR THRUST BEARING INSTALLA-
TION
A) For installation of thrust bearings on VSG and
VSSG units:
1) Install bearings (126) in the housing so the
bearings are face to face.
The larger sides of the inner races are
placed together. A light application of
clean compressor lubricating oil should
be used to ease the installation of the
bearings into the housing.
2) Center the bearing retainer ring on housing, use Loctite® 242-thread locker and
evenly tighten the bolts to the recommended torque value.
Service
3) For installation of the bearing housing and
the setting of the gate rotor blade clearance, refer to section INSTALLATION (All
VSG Models).
B) For installation of thrust bearings on VSG 301-
701 units:
1) Install retainer in the back of the inner race
of one of the thrust bearings. The back of
the inner race is the narrower of the two
sides.
2) The bearing with the retainer should
be placed in the housing first, retainer
towards the support. Install the second
bearing. The bearings should be positioned face to face. This means that the
larger sides of the inner races are placed
together. A light application of clean compressor lubricating oil should be used to
ease the installation of the bearings into
the gate rotor support.
3) Install the bearing retaining snap ring.
Inner Retainer
Ball Bearings
Retaining Ring
4) For installation of the bearing housing and
the setting of the gate rotor blade clearance, refer to section INSTALLATION (All
VSG Models).
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Service
GATE ROTOR ROLLER BEARING REMOVAL
A) Refer to section REMOVAL ( All VSG) for removal
B) Remove the snap ring (131), which retains the
C) Remove the roller bearing (125) from the bearing
D) Use a bearing puller to remove the roller bearing
GATE ROTOR ROLLER BEARING INSTALLATION
A) Match up the part numbers on the inner race to
of the gate rotor bearing housings and gate rotor
supports.
roller bearing in the bearing housing.
housing (112).
race (125) from the gate rotor support (110).
the part numbers outer race. Press the bearing
race (numbers visible) onto the gate rotor support.
B) Install the outer bearing into the bearing housing
so the numbers match the numbers on the inner
race. Install the snap ring retainer in the housing.
The bevel on the snap ring must face away from
the roller bearing.
C) For installation of the bearing housing, refer to
section INSTALLATION (All VSG Models).
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Service
COMPRESSOR SHAFT SEAL REPLACEMENT
COMPRESSOR SHAFT SEAL REMOVAL
A) Prepare the compressor for servicing as outlined
in section REMOVAL ( All VSG) .
B) Remove bolts (281) holding the shaft seal cover
(218). Insert two of the bolts into the threaded
jacking holes to assist in removing the cover.
There will be a small amount of oil drainage as
the cover is removed.
C) Remove the rotating portion of the shaft seal
(219C).
D) Remove oil seal (230) from cover.
Seal with stationary mirror face (219B) and
rotating carbon face (219C).
Seal with stationary carbon face (219B)
and rotating mirror face (219C).
Current Shaft Seal and for all Replacement.
E) Remove the stationary portion of the shaft seal
(219B) from the seal cover using a brass drift and
hammer to tap it out from the back side of the
seal cover.
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Service
COMPRESSOR SEAL INSTALLATION
When replacing the stationary members of the seal on
the VSSG 291 thru VSSG 601 the roll pin in the cover
is used only with the seal assembly having a stationary mirror face. If a seal assembly with a stationary
carbon face is installed, the roll pin must be removed.
A) Install new oil seal in cover.
NOTE:
CAUTION
Care must be taken when handling the shaft seal and
mirror face so it is not damaged. Do not touch the
carbon or mirror face as body oil and sweat will cause
the mirror face to corrode.
B) To install the carbon cartridge part of the seal
in the seal cover; clean the seal cover, remove
protective plastic from the carbon cartridge, do
not wipe or touch the carbon face. Lubricate the
sealing O-ring with clean compressor lubricating
oil. If applicable, align the hole on the back of
the carbon cartridge with the dowel pin in the
seal cover. Install cartridge using seal installation
tool or similar (see tool lists).
C) Wipe clean, the compressor input shaft and the
shaft seal cavity in the compressor housing. Apply clean compressor oil to the shaft seal seating
area on input shaft.
D) Lubricate the inside area of the rotating seal with
clean compressor lubricating oil, do not wipe
or touch the face of the rotating portion of the
seal. Align the slot in the rotating seal with the
drive pin on the compressor input shaft. Carefully push the seal on, holding onto the outside
area of the seal until the seal seats against the
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Service
shoulder on the input shaft. Make sure the seal
is seated against the shoulder. If the seal is not
fully seated against the shoulder, the shaft seal
carbon will be damaged when the seal cover is
installed.
Maintenance Suggestion:
A spray bottle lled with clean compressor oil
may be used to lubricate the faces of the seals
without touching the seal.
E) Install a new O-ring on the seal cover, making
sure the O-ring is placed in the O-ring groove
and not the oil gallery groove. Lubricate both
seal faces with clean compressor lubricating oil.
F) Carefully install the seal cover on the compressor
shaft, evenly tightening the bolts to the recommended torque values.
G) Install the coupling and coupling guard. The unit
can then be evacuated and leak checked.
MAIN ROTOR ASSEMBLY
Due to the procedures and tools involved in the disassembly and reassembly, the main rotor assembly must
be performed by qualied individuals.
Please consult the factory if maintenance is required.
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Service
INSPECTION OF SLIDE VALVE ASSEMBLIES IN
THE COMPRESSOR
Prepare the compressor for servicing.
A) Remove the gate rotor access covers. Using a
mirror and ashlight, visually inspect the slide
valve carriage through the gas bypass opening.
Look for any signicant signs of wear on the slide
valve carriage.
B) To check the clearance of the slide valve clamps,
the gate rotor support must be removed. Refer
to removal of the gate rotor support.
C) Using a feeler gauge, inspect the clearance be-
tween capacity and volume slide valve clamps
and slide valve carriage through the gas bypass
opening. The clearance should be less than
0.002”.
D) If the slide valves are worn in excess of the toler-
ances, the factory should be contacted.
REMOVAL SLIDE VALVE CARRIAGE ASSEM-
BLIES
A) Prepare the compressor for servicing.
B) If only one of the slide valve carriages is removed
only the corresponding gate rotor support
needs to be removed. If both carriages are
removed both gate rotors must be removed.
Remove the gate rotor assemblies.
C) Remove the capacity and volume actuators.
Remove the discharge manifold, capacity and
volume cross shafts and the slide valve racks.
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Service
D) Locate and remove the socket head plugs above
the slide valve carriage attachment bolts. Remove the bolts located under the plugs.
E) The slide valve carriage may now be removed.
On newer carriages there is a threaded hole in
the back of the slide valve carriage to aid in its
removal. Use a threaded tip slide hammer to aid
in the removal of the carriage.
Note: Slide Valves may be re-positioned to aid in
removal of assembly.
INSTALLATION OF SLIDE VALVE CARRIAGE AS-
SEMBLIES
A) Position the slide valves to the center of the car-
riage. Place the slide valve assembly in the bore of
frame and use the slide hammer to slowly tap the
carriage into position. Re-positioning slide valves
once inside bore may aid installation. Adjust the
carriage so that the 3-holes line up.
B) Install the 3 socket head cap screws with new
Nord-Lock washers beneath the heads, but do
not tighten them.
C) Work a piece of 0.005”shim stock between the
slide valves and the main rotor to help position
the carriage.
D) Tighten, to the correct torque the hold down
bolts to secure the carriage in the frame. The
edges of the slide valves themselves should be
at or slightly below the main rotor bore.
E) Re- Install the capacity and volume slide valve
cross shafts, slide valve racks and discharge
manifold.
F) Re-install the gate rotor assemblies.
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Service
COMMAND SHAFT ASSEMBLY REMOVAL
The following steps can be used to remove or install
either the capacity or volume command shaft assemblies.
A) Prepare the compressor for servicing.
B) Follow the appropriate instructions to remove
control actuator. .
C) Remove four socket head cap screws (457) and
Nord-Lock washers (477) securing mounting
plate (415) to manifold.
D) The command shaft and mounting plate may
now be removed from the compressor.
4 7 7
4 5 7
4 1 5
B) Install the actuator mounting plate with the four
socket head cap screws and Nord-Lock washers
securing it with proper torque.
C) The unit can now be leak checked.
COMMAND SHAFT ASSEMBLY INSTALLATION
A) Install the command shaft assembly with a new
o-ring (446) on the manifold. Make sure that the
command shaft tongue is engaged in the cross
shaft slot. Rotate the bearing housing so the
vent holes point down, this will prevent water
and dust from entering the vents.
COMMAND SHAFT BEARING AND O-RING SEAL
REPLACEMENT
A) Remove command shaft assembly.
B) Remove snap ring retainer (451) from command
shaft housing (412). Push the command shaft assembly out of the housing.
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C) The command shaft bearing (435) is a press
t on the command shaft (413). Remove the
command shaft bearing with a suitable press.
Ve n t h ole .
43 6
44 5
Reference “Parts
Section” for current
Housing
D) Remove the O-ring seal (445) from the com-
mand shaft housing. The command shaft bushing (433 and 436) might have to be removed to
gain access to o-rings. Replace bushing if the
bore is deeply scored or excessively worn.
COMMAND SHAFT BEARING AND O-RING
SEAL REASSEMBLY
DISCHARGE MANIFOLD REMOVAL
A) Remove both control actuators and command
shaft assemblies.
B) On VSG751-2101 and VSSG 291-601 compres-
sors, remove the discharge spool between the
manifold and separator. Remove one bolt from
each side of the discharge manifold and install
(2) guide rods approximately 6” long, to support
the manifold. Remove the remaining bolts (note
length and location of bolts) and take off the
discharge manifold.
Note: Mainfold has dowel pins to locate it on the
compressor housing. Therefore, remove manifold
straight back approximately 1” as not to break
dowel pins.
A) Install new O-ring seal in housing and lubricate
the O-ring with clean compressor oil. A vent
hole is provided in the command shaft bearing
housing to allow any refrigerant and oil that may
leak past the O-ring seal to vent to atmosphere
and not into the slide valve motor housing.
Install snap ring retainer and washer on the
command shaft.
B) Remove any burrs from the command shaft to
prevent damage to the O-ring when assembling.
Press the command shaft bearing onto the
command shaft. Insert the command shaft into
the housing applying pressure on outer race of
bearing. Make sure the bearing is fully seated
in the command shaft housing. Install the snap
ring retainer in the command shaft housing.
C) Install command shaft assembly.
50
NOTE:
When removing the discharge manifold on VSG 301-701
compressor the compressor must be properly supported
to keep the compressor from moving when the manifold
is removed.
C) On VSG 301-701 compressors unbolt the dis-
charge ange from the discharge manifold.
D) Remove one bolt from each side of the discharge
manifold and install (2) guide rods approximately
6” long, to support the manifold. Remove the
remaining bolts (note length and location of bolts)
and take off the discharge manifold.
Page 51
Service
DISCHARGE MANIFOLD INSTALLATION
A) Install (2) guide rods to position the discharge
manifold. Install a new manifold gasket and
the discharge manifold. Install the dowel pins
and bolts, tighten manifold bolts to the recommended torque value.
B) On VSG 751-2101 and VSSG 291-601 compres-
sors install the discharge spool or elbow between the discharge manifold and oil separator
with new gaskets. When installing the discharge
elbow tighten the bolts to the correct torque on
the manifold ange rst before tightening the
separator ange bolts. Install the drain plug in
the bottom of the discharge manifold.
C) On VSG 301-701 compressors install the bolts
in the discharge ange. Install the drain plug in
the bottom of the discharge manifold.
D) Install both command shaft assemblies and
control actuators.
F) Look for any excessive wear on all moving parts
and replace the worn parts.
G) Reassemble the manifold and discharge elbow.
REMOVAL OF CAPACITY OR VOLUME CROSS
SHAFTS
A) Remove the discharge manifold.
SLIDE VALVE GEAR AND RACK INSPECTION
A) Remove the discharge manifold.
B) Check rack to rack clamp and rack clamp spacer
clearance on all four slide valves.
TABLE 4.1
RACK CLEARANCE VALUES
MEASUREMENT CLEARANCE
Rack to clamp. 0.005 to 0.010”
Rack to clamp spacer. 0.003 to 0.005”
C) Check torque of socket heat cap screws.
D) Check for excessive movement between the
slide valve rack shafts and the rack. The jam nuts
on the end of the slide valve rack shaft should be
tight.
E) Check for loose or broken roll pins in gears.
B) To remove the capacity or volume ratio slide
valve racks, remove the two jam nuts and lock
washers (361) securing the rack (316) to the slide
valve shafts. The racks can now be pulled off the
slide valve shafts. Repeat the procedure for the
remaining pair of slide valve racks.
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Service
C) To remove the cross shafts, remove socket head
bolts, clamp and spacers from both sides.
VSG 751-2101 compressors cross shafts.
VSSG 291-601 compressors cross shafts
Volume control cross shaft.
INSTALLATION OF CAPACITY OR VOLUME
CROSS SHAFTS
A) To reassemble either set of capacity or volume
ratio slide valve racks, install the cross shaft with
the pinion gear onto the back plate, place the
remaining pinion gear on the shaft and drive in
the roll pins. Install clamps, spacers and bolts
on both sides. Tighten the bolts to the recommended torque values.
B) The slide valve sets must be synchronized on VSG
751-2101 and dual gate VSG 301-701 units. Both
slide valve racks for either the volume ratio or
capacity slide valves must engage the cross shaft
gears at the same time. Push the racks all the way
towards the suction end of the compressor until
they stop. Install washers and jam nuts on the
slide valve shafts. Repeat the procedure for the
remaining set of slide valve racks.
Capacity control cross shaft.
D) Drive the roll pins from pinion gear from one
side. Remove pinion gear. Slide the cross shaft
with the remaining pinion gear or spacers out of
the opposite side. Repeat the procedure for the
remaining cross shaft.
52
C) Install (2) guide rods to position the discharge
manifold. Install a new manifold gasket and
the discharge manifold. Install the dowel pins
and bolts, tighten manifold bolts to the recommended torque value.
D) On VSG 751-2101 and VSSG 291-601 and VSG
301-701 compressors install the discharge.
Page 53
Service
TORQUE SPECIFICATIONS (ALL UNITS IN FT.-LBS)
HEAD OUTSIDE DIAMETER OF BOLT SHANK
TYPE BOLT MARKINGS
1
/4”
5
/16”
3
/8”
7
/16”
1
/2”
9
/16”
5
/8”
3
/4”
SAE GRADE 2 6 12 20 32 47 69 96 155
SAE GRADE 5 10 19 33 54 78 114 154 257
SAE GRADE 8 14 29 47 78 119 169 230 380
SOCKET HEAD 16 33 54 84 125 180 250 400
CAP SCREW
TORQUE SPECIFICATION FOR 17-4 STAINLESS STEEL FASTENERS (FT-LBS)
TYPE ¼” 5/16” 3/8” 7/16” ½” 9/16” 5/8” ¾”
HEX & SOCKET
HEAD CAP 8 14 25 40 60 101 137 245
SCREW
NUT 8
NOTE: CONTINUE USE OF RED LOCTITE ON CURRENTLY APPLIED LOCATIONS. USE BLUE
LOCTITE ON ALL REMAINING LOCATIONS.
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Service
USING A TORQUE WRENCH CORRECTLY
TORQUE WRENCHES
USING A TORQUE WRENCH CORRECTLY INVOLVES FOUR PRIMARY CONCERNS:
A. A smooth even pull to the break point is required. Jerking the wrench can cause the pivot point
to break early leaving the bolt at a torque value lower then required. Not stopping when the
break point is reached results in an over torque condition.
B. When more than one bolt holds two surfaces together there is normally a sequence that
should be used to bring the surfaces together in an even manner. Generally bolting is tightened incrementally in a diametrically staggered pattern. Some maintenance manuals specify
a tightening scheme. If so, the manual scheme shall be followed. Just starting on one side and
tightening in a circle can cause the part to warp, crack, or leak.
C. In some cases threads are required to be lubricated prior to tightening the bolt/nut. Whether
a lubricant is used or not has considerable impact on the amount of torque required to achieve
the proper preload in the bolt/stud. Use a lubricant, if required, or not if so specied.
D. Unlike a ratchet wrench a torque wrench is a calibrated instrument that requires care. Recali-
bration is required periodically to maintain accuracy. If you need to remove a bolt/nut do not
use the torque wrench. The clockwise/counterclockwise switch is for tightening right hand or
left hand threads not for loosening a fastener. Store the torque wrench in a location where it
will not be bumped around.
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Service
A. The Nord-Lock® lock washer sets are used in many
areas in both the VSG & VSSG screw compressors that
require a vibration proof lock washer.
B. The lock washer set is assembled so the course
serrations that resemble ramps are mated together.
C. Once the lock washer set is tightened down, it
takes more force to loosen the bolt that it did to
tighten it. This is caused by the washers riding up
the opposing ramps.
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56
Page 57
Parts Section
Recommended
Spare Parts List
Refer to the Custom Manual
Spare Parts Section for Specic Applications
Please have your Model # and Sales Order # available when ordering.
These are found on the compressor’s Name Plate.
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Page 58
Gate Rotor
58
Page 59
Gate Rotor
MODEL NUMBER
ITEM DESCRIPTION VSSG 451 VSSG 601
QTY VPN QTY VPN
GATE ROTOR BLADE AND BEARING
REPLACEMENT KIT, 111, 118, 120A,
120B, 121, 122, 123, 124, 125, 126,
130, 131, 141, 142 & 143. 2 KT712A 2 KT712B
GATE ROTOR BLADE REPLACE
KIT, 111, 118, 120A, 120B, 121, 122,
123, 124, 130, 141, 142 & 143. 2 KT713A 2 KT713B
102 GATE ROTOR SUPPORT ASSEMBLY
100, 111, 120B, 119 & 130. 2 A25161BB 2 A25161BA
105 GATE ROTOR GASKET SET 118, 141,
142 & 143. 2 A25164B 2 A25164B
106 SHIM PACK SET (2) 121, (2) 122,
(1) 123, (1) 124. 2 A25165B 2 A25165B
110 SUPPORT. 2 25606A 2 25520A
111 GATE ROTOR. 2 25557A 2 25534A
112 SMALL BEARING HOUSING.
113 LARGE BEARING HOUSING.
114 RETAINER.
115 RETAINER.
116 BALL BEARING COVER.
117 GATE ROTOR COVER.
118 GATE ROTOR COVER GASKET.
119 WASHER.
120A BUSHING, SMALL DOWEL PIN.
120B BUSHING, LARGE DOWEL PIN.
121 SHIM 0.002”.
122 SHIM 0.003”.
123 SHIM 0.005”.
124 SHIM 0.010”.
125 ROLLER BEARING.
126 BALL BEARING.
130 RETAINING RING.
131 RETAINING RING.
135A DOWEL PIN, SM, 0.250” O.D..
135B DOWEL PIN, LG, 0.4375” O.D..
141 O-RING ROLLER BRG HSG.
142 O-RING BALL BRG HSG.
143 O-RING BRG HSG COVER.
150 HEX HEAD CAP SCREW.
151 HEX HEAD CAP SCREW.
152 HEX HEAD CAP SCREW.
153 HEX HEAD CAP SCREW.
160 SOCKET HEAD CAP SCREW.
2 25518A
2 25517A
2 25008A
2 25009A
2 25258A
2 25519A
2 25259A
2 25007A
2 25006A
2 25760A
ar 25010AA
ar 25010AB
ar 25010AC
ar 25010AD
2 2864B
4 2865B
2 2866A
2 2867A
2 2868B
2 25910A
2 2176M
2 2176R
2 2176N
12 2796AJ
6 2796B
40 2796CJ
32 2796E
12 2795E
2 25518A
2 25517A
2 25008A
2 25009A
2 25258A
2 25519A
2 25259A
2 25007A
2 25006A
2 25760A
ar 25010AA
ar 25010AB
ar 25010AC
ar 25010AD
2 2864B
4 2865B
2 2866A
2 2867A
2 2868B
2 25910A
2 2176M
2 2176R
2 2176N
12 2796AJ
6 2796B
40 2796CJ
32 2796E
12 2795E
NOTE: ar = As Required
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Gate Rotor
ITEM DESCRIPTION VSG 751 VSG 901 VSG 1051 VSG 1201
QTY VPN QTY VPN QTY VPN QTY VPN
GATE ROTOR BLADE AND BEARING
REPLACEMENT KIT, 111, 118, 120A,
120B, 121, 122, 123, 124, 125, 126,
130,131, 141, 142 & 143. 2 KT712C 2 KT712D 2 KT712E 2 KT712F
GATE ROTOR BLADE REPLACE
KIT, 111, 118, 120A, 120B, 121, 122,
123, 124, 130, 141, 142 & 143. 2 KT713C 2 KT713D 2 KT713E 2 KT713F
102 GATE ROTOR SUPPORT ASSEMBLY
100, 111, 120B, 119 &130 2 A25161CB 2 A25161CA 2 A25161DB 2 A25161DA
105 GATE ROTOR GASKET SET 118, 141,
142 & 143. 2 A25164C 2 A25164C 2 A25164D 2 A25164D
SHIM PACK SET (2) 121, (2) 122,
(1) 123, (1) 124. 2 A25165C 2 A25165C 2 A25165C 2 A25165C
110 SUPPORT. 2 25612A 2 25553A 2 25614A 2 25587A
111 GATE ROTOR. 2 25608A 2 25554A 2 25610A 2 25588A
118 GATE ROTOR COVER GASKET. 2 25088A 2 25088A 2 25132A 2 25132A
119 WASHER. 2 25086A 2 25086A 2 25086A 2 25086A
120A BUSHING, SMALL DOWEL PIN. 2 25087A 2 25087A 2 25104A 2 25104A
120B BUSHING, LARGE DOWEL PIN. 2 25760B 2 25760B 2 25760B 2 25760B
121* SHIM 0.002”. ar 25089AA ar 25089AA ar 25089AA ar 25089AA
122* SHIM 0.003”. ar 25089AB ar 25089AB ar 25089AB ar 25089AB
123* SHIM 0.005”. ar 25089AC ar 25089AC ar 25089AC ar 25089AC
124* SHIM 0.010”. ar 25089AD ar 25089AD ar 25089AD ar 25089AD
125 ROLLER BEARING. 2 2864C 2 2864C 2 2864G 2 2864G
126 BALL BEARING. 4 2865A 4 2865A 4 2865A 4 2865A
130 RETAINING RING. 2 2866B 2 2866B 2 2866B 2 2866B
131 RETAINING RING. 2 2867E 2 2867E 2 2867L 2 2867L
135A DOWEL PIN, SMALL, 0.3125” O.D.. 2 2868F 2 2868F 2 2868H 2 2868H
135B DOWEL PIN, LARGE, 0.4375” O.D.. 2 25910B 2 25910B 2 25910B 2 25910B
141 O-RING ROLLER BRG HSG. 2 2176N 2 2176N 2 2176AJ 2 2176AJ
142 O-RING BALL BRG HSG. 2 2176V 2 2176V 2 2176AM 2 2176AM
143 O-RING BRG HSG COVER. 2 2176U 2 2176U 2 2176U 2 2176U
ar = As Required
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Gate Rotor
ITEM DESCRIPTION VSG 1551 VSG1851 VSG 2101
QTY VPN QTY VPN QTY VPN
GATE ROTOR BLADE AND BEARING
REPLACEMENT KIT, 111, 118, 120A,
120B, 121, 122, 123, 124, 125, 126, 130,
131, 141, 142 & 143. 2 KT712M 2 KT712L 2 KT712K
GATE ROTOR BLADE REPLACEMENT
KIT, 111, 118, 120A, 120B, 121, 122, 123,
124, 130, 141, 142 & 143. 2 KT713N 2 KT713M 2 KT713L
101 GATE ROTOR ASSEMBLY 111 & 120. 2 A25160EB 2 A25160EA 2 A25160EA
102 GATE ROTOR SUPPORT ASSEMBLY
100, 111, 120B, 119 &130. 2 A25161EB 2 A25161EA 2 A25161EL
105 GATE ROTOR GASKET SET 118, 141,
142 & 143. 2 A25164E 2 A25164E 2 A25164E
SHIM PACK SET (2) 121, (2) 122,
(1) 123, (1) 124. 2 A25165E 2 A25165E 2 A25165E
110 SUPPORT. 2 25687A 2 25665A 2 25495D
111 GATE ROTOR. 2 25647A 2 25645A 2 25744D
112 SMALL BEARING HOUSING. 2 25667A 2 25667A 2 25667A
113 LARGE BEARING HOUSING. 2 25669A 2 25669A 2 25669A
114 RETAINER. 2 25141A 2 25141A 2 25141A
115 RETAINER. 2 25789A 2 25789A 2 25789A
116 BALL BEARING COVER. 2 25351A 2 25351A 2 25351A
117 GATE ROTOR COVER. 2 25354A 2 25354A 2 25354A
118 GATE ROTOR COVER GASKET. 2 25790A 2 25790A 2 25790A
119 WASHER. 2 25788A 2 25788A 2 25788A
120A BUSHING, SMALL DOWEL PIN. 2 25104A 2 25104A 2 25104A
120B BUSHING, LARGE DOWEL PIN. 2 25760C 2 25760C 2 25760C
121* SHIM 0.002”. ar 25791AA ar 25791AA ar 25791AA
122* SHIM 0.003”. ar 25791AB ar 25791AB ar 25791AB
123* SHIM 0.005”. ar 25791AC ar 25791AC ar 25791AC
124* SHIM 0.010”. ar 25791AD ar 25791AD ar 25791AD
125 ROLLER BEARING. 2 2864K 2 2864K 2 2864K
126 BALL BEARING. 4 2865K 4 2865K 4 2865K
130 RETAINING RING. 2 2866G 2 2866G 2 2866G
131 RETAINING RING. 2 2867R 2 2867R 2 2867R
135A DOWEL PIN, SMALL, 0.375” O.D.. 2 2868H 2 2868H 2 2868H
135B DOWEL PIN, LARGE, 0.500” O.D.. 2 25910C 2 25910C 2 25910C
141 O-RING ROLLER BRG HSG. 2 2176U 2 2176U 2 2176U
142 O-RING BALL BRG HSG. 2 2176BD 2 2176BD 2 2176BD
143 O-RING BRG HSG COVER. 2 2176P 2 2176P 2 2176P
150 HEX HEAD CAP SCREW. 12 2796CJ 12 2796CJ 12 2796CJ
151 HEX HEAD CAP SCREW. 8 2796N 8 2796N 8 2796N
152 HEX HEAD CAP SCREW. 32 2796CJ 32 2796CJ 32 2796CJ
153 HEX HEAD CAP SCREW. 44 2796R 44 2796R 44 2796R
160 SOCKET HEAD CAP SCREW. 16 2795G 16 2795G 16 2795G
ar = As required
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Shaft Seal
Shaft Seal With Stationary Carbon Face
MODEL NUMBER
ITEM DESCRIPTION VSSG 291-601 VSG 751-1201 VSG 1551 thru 2101
QTY VPN QTY VPN QTY VPN
SHAFT SEAL VITON KIT, 219, 260, 230 1 KT709AG 1 KT709BG 1 KT709CG
230 OIL SEAL. 1 25040A 1 25064A 1 2930B
260 O-RING. 1 2176F 1 2176AC 1 2176BH
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Tandem Shaft Seal
SHAFT DIAMETER
DESCRIPTION 2.25” 2.5” 2.875”
QTY VPN QTY VPN QTY VPN
TANDEM SHAFT SEAL 1 25713A 1 25713A 1 25713A
1 25713B 1 25713B 1 25713B
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Main Rotor
64
Page 65
MODEL NUMBER
ITEM DESCRIPTION VSSG 451 VSSG 601 VSG 751 VSG 901 VSG 1051 VSG 1201 VSG 1551 VSG 1851 VSG 2101
QTY PART# QTY PART# QTY PART# QTY PART# QTY PART# QTY PART# QTY PART# QTY PART# QTY PART#
201 ROTOR ASSY 1 A25168BB 1 A25168BA 1 A25168CB 1 A25168CA 1 A25168DB 1 A25168DA 1 A25168EB 1 A25168AE 1 A25225EE
(DOES NOT INCLUDE
SHIM PACK #207)
207 SHIM PACK 1 A25177B 1 A25177B 1 A25177C 1 A25177C 1 A25177D 1 A25177D 1 A25177E 1 A25177E 1 A25177E
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Slide Valve Cross Shafts and End Plate
66
Page 67
Slide Valve Cross Shafts and End Plate
MODEL NUMBER
VSSG 291-601
ITEM DESCRIPTION QTY VPN
221 SHAFT. 2 25843A
222 GEAR. 4 25027A
226 RACK CLAMP. 2 25913A
227 RACK CLAMP. 2 25913B
228 SPACER. 2 25847A
268 EXPANSION PIN. 4 1193D
269 EXPANSION PIN. 4 2981AA
286 SOCKET HEAD CAP SCREW. 8 2795F
297 SET SCREW 2 2060J
298 SET SCREW 2 2060H
MODEL NUMBER
ITEM DESCRIPTION VSG 751 & VSG 901 VSG 1051 & VSG 1201
QTY VPN QTY VPN
220 END PLATE 1 25543A 1 25593A
221 SHAFT. 2 25844A 2 25845A
222 GEAR. 4 25027A 4 25027A
226 RACK CLAMP. 4 25913C 4 25913C
228 SPACER. 4 25033C 4 25033C
267 DOWEL PIN. 2 2868B 2 2868B
268 EXPANSION PIN. 4 1193D 4 1193D
269 EXPANSION PIN. 4 2981AA 4 2981AA
270 PIPE PLUG. 2 2606E 2 2606E
286 SOCKET HEAD CAP SCREW. 8 2795F 8 2795F
297 SET SCREW 2 2060J 2 2060J
298 SET SCREW 2 2060H 2 2060H
MODEL NUMBER
ITEM DESCRIPTION VSG 1551Thru VSG 2101
QTY VPN
220 END PLATE 1 25661A
221 SHAFT. 2 25793A
222 GEAR. 4 25027A
226 RACK CLAMP. 4 25913C
228 SPACER. 4 25033C
267 DOWEL PIN. 2 2868B
268 EXPANSION PIN. 4 1193D
269 EXPANSION PIN. 4 2981AA
270 PIPE PLUG. 2 2606A
286 SOCKET HEAD CAP SCREW. 8 2795F
297 SET SCREW 2 2060J
298 SET SCREW 2 2060H
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Slide Valve Carriage Assembly
Carriage Assembly
Volume Slide
Capacity Slide
68
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Slide Valve Carriage Assembly
MODEL NUMBER-
ITEM DESCRIPTION VSSG 291 Thru VSSG 601
QTY VPN
300 CARRIAGE ASSEMBLY. 2 A25179B
304 CAPACITY PISTON 340, 341, 350 & 355 2 A25183B
305 VOLUME PISTON 340, 342, 350 & 355 2 A25184B
307 GASKET SET 345B. 2 A25200B
316 RACK. 2 25024A
323 RACK. 2 25023A
343A COVER, SEPARATE VOL. & CAP. 4 25022A
343B COVER, ONE PIECE CAST. 2 25399A
345A GASKET, SEPARATE VOL. & n/a
CAP COVERS. 4 25021A
345B GASKET, ONE PIECE CAST COVER. 2 25900A
350 PISTON RING SET. 4 2953AA
355 EXPANSION PIN. 4 1193PP
359 PIPE PLUG. 6 2606D
360 LOCK WASHER (PAIR). 4 3004C
361 WASHER. 4 13265B
363 NUT. 8 2797A
366A HEX HEAD CAP SCREW, SEPARATE
VOL. & CAP COVERS. 24 2796N
366B HEX HEAD CAP SCREW, ONE PIECE
CAST COVER. 24 2796B
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Slide Valve Carriage Assembly
MODEL NUMBER
ITEM DESCRIPTION VSG 751 VSG 901 VSG 1051 VSG 1201
QTY VPN QTY VPN QTY VPN QTY VPN
300 CARRIAGE ASSEMBLY. 2 A25179C 2 A25179C 2 A25179D 2 A25179D
304 CAPACITY PISTON 340, 341, 350 & 355. 2 A25183C 2 A25183C 2 A25183D 2 A25183D
305 VOLUME PISTON 340, 342, 350 & 355. 2 A25184C 2 A25184C 2 A25184D 2 A25184D
307 GASKET SET 345B & 378**. 2 A25200C 2 A25200C 2 A25200D 2 A25200D
316 RACK. 2 25080A 2 25080A 2 25080C 2 25080C
323 RACK. 2 25080B 2 25080B 2 25080D 2 25080D
340 PISTON. 4 25076A 4 25076A 4 25138A 4 25138A
341 CAPACITY PISTON SHAFT. 2 25078A 2 25078A 2 25078E 2 25078E
342 VOLUME PISTON SHAFT. 2 25078B 2 25078B 2 25078F 2 25078F
343A COVER, SEPARATE VOL. & CAP. 2 25123B 2 25123B 4 25123C 4 25123C
343B COVER, ONE PIECE CAST. 2 25279A 2 25279A 2 25401A 2 25401A
344 COVER, SEPARATE VOL. & CAP. 2 25123A 2 25123A n/a n/a n/a n/a
345A GASKET, SEPARATE VOL. &
CAP COVERS. 2 25124B 2 25124B 4 25124C 4 25124C
345B GASKET ONE PIECE CAST COVER. 2 25902A 2 25902A 2 25901A 2 25901A
346 GASKET, SEPARATE VOL. & CAP
COVERS. 2 25124A 2 25124A n/a n/a n/a n/a
347 PISTON SLEEVE. 2 25079A 2 25079A n/a n/a n/a n/a
350 PISTON RING SET. 4 2953AB 4 2953AB 4 2953AC 4 2953AC
355 EXPANSION PIN. 4 1193PP 4 1193PP 4 1193PP 4 1193PP
359 PIPE PLUG. 6 2606D 6 2606D 6 2606E 6 2606E
360 LOCK WASHER (PAIR). 4 3004C 4 3004C 4 3004C 4 3004C
361 WASHER. 4 13265B 4 13265B 4 13265B 4 13265B
363 NUT. 8 2797A 8 2797A 8 2797A 8 2797A
366A HEX HEAD CAP SCREW. 12 2796B 12 2796B 24 2796B 24 2796B
366B HEX HEAD CAP SCREW. 12 2796P 12 2796P 24 2796P 24 2796P
367 HEX HEAD CAP SCREW. 12 2796BN 12 2796BN n/a n/a n/a n/a
373 SOCKET HEAD CAP SCREW. 6 2795N 6 2795N 6 2795P 6 2795P
374 LOCK WASHER (PAIR). 6 3004C 6 3004C 6 3004D 6 3004D
378 0-RING. 2 2176Y 2 2176Y n/a n/a n/a n/a
380 RETAINER RING. 2 2866C 2 2866C n/a n/a n/a n/a
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Slide Valve Carriage Assembly
MODEL NUMBER
ITEM DESCRIPTION VSG 1551 to 2101
QTY VPN
300 CARRIAGE ASSEMBLY. 2 A25179E
304 CAPACITY PISTON 340, 341, 350 & 355 2 A25183E
305 VOLUME PISTON 340, 342, 350 & 355 2 A25184E
307 GASKET SET 345 & 378. 2 A25200E
316 RACK. 2 25779A
323 RACK. 2 25780A
325 SHAFT. 2 25778A
340 PISTON. 4 25782A
341 CAPACITY PISTON SHAFT. 2 25784A
342 VOLUME PISTON SHAFT. 2 25783A
343B COVER. 2 25690A
345B GASKET. 2 25384A
347 PISTON SLEEVE. 4 25786A
350 PISTON RING SET. 4 2953AD
355 EXPANSION PIN. 4 1193PP
359 PIPE PLUG. 6 2606E
360 LOCK WASHER (PAIR). 4 3004C
361 WASHER. 4 13265B
363 NUT. 8 2797A
366B HEX HEAD CAP SCREW. 28 2796BL
373 SOCKET HEAD CAP SCREW. 6 2795AG
374 LOCK WASHER (PAIR). 6 3004D
378 0-RING. 4 2176AG
380 RETAINER RING. 4 2755AG
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Actuator & Command Shaft
72
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Actuator & Command Shaft
MODEL NUMBER
VSSG 291 thru VSG 751 thru VSG 1051 thru VSG 1551 thru
ITEM DESCRIPTION VSSG 601 VSSG 901 VSG 1201 VSG 2101
QTY VPN VPN VPN VPN
400 COMMAND SHAFT ASSEMBLY 2 A25994B A25994C A25994D A25994E
401 SLIDEVALVE ACUATOR 2 25972D 25972D 25972D 25972D
446 O-RING 2 2176X 2176X 2176X 2176X
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VSG Screw Compressor
Miscellaneous Frame Components
74
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Miscellaneous Frame Components
MODEL NUMBER
ITEM DESCRIPTION VSSG 291 thru
VSSG 601
QTY VPN
GASKET AND O-RING KIT; 1 KT710A1
504 FLANGE SET 513, 514 & 547A. 1 A25190A
506 ECON-O-MIZER PORT. 2 A25190B
512 MANIFOLD GASKET. 1 25503A
513 FLANGE OIL. 1 25058A
513 AFLANGE ECON-O-MIZER. 2 25058A
514 FLANGE GASKET OIL. 1 11323D
514A FLANGE GASKET ECON-O-MIZER. 2 11323D
518 SUCTION FLANGE GASKET. 1 25199C
519 DISCHARGE FLANGE GASKET. 1 25199B
524 COVER. n/a n/a
525 GASKET. n/a n/a
527 INLET SCREEN. n/a n/a
528 ECON-O-MIZER PLUG. n/a n/a
530 O-RING 2 2176AB
532 O-RING n/a n/a
535 PIPE PLUG 1/4” MPT. n/a n/a
539 PIPE PLUG. n/a n/an/an/a
540 DOWEL PIN. 2 2868B
545 HEX HEAD CAP SCREW FOR OIL n/a n/a
SUPPLY FLANGE. 2 2796C
545 HEX HEAD CAP SCREW FOR n/a n/a
ECON-O-MIZER FLANGE. 4 2796C
547 HEX HEAD CAP SCREW. 8 2796C
552 HEX HEAD CAP SCREW. n/a n/a
552 HEX HEAD CAP SCREW. n/a n/a
553 HEX HEAD CAP SCREW. n/a n/a
650 O-RING. n/a n/a
651 O-RING. n/a n/a
75
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Miscellaneous Frame Components
MODEL NUMBER
ITEM DESCRIPTION VSG 751 VSG 901 VSG 1051 VSG 1201
QTY VPN QTY VPN QTY VPN QTY VPN
GASKET AND O-RING KIT; 1 KT710B 1 KT710B 1 KT710C 1 KT710C
504 FLANGE SET 513, 514 & 547. 1 A25190A 1 A25190A 1 A25190B 1 A25190B
512 MANIFOLD GASKET. 1 25541A 1 25541A 1 25324A 1 25324A
513 FLANGE OIL. 1 25058A 1 25058A 1 25058B 1 25058B
514 FLANGE GASKET OIL. 1 11323D 1 11323D 1 11323E 1 11323E
518 SUCTION FLANGE GASKET. 1 25199C 1 25199C 1 25199D 1 25199D
519 DISCHARGE FLANGE GASKET. 1 25199B 1 25199B 1 25199C 1 25199C
526 ORIFICE PLATE. 1 25223CB 1 25223CA 1 25223DB 1 25223DB
529 WAVE SPRING. 1 2912E 1 2912E 1 2912E 1 2912E
530 O-RING 2 2176J 2 2176J 2 2176J 2 2176J
538 PIPE PLUG 3/4” MPT. 6 2606A 6 2606A
540 DOWEL PIN. 2 2868B 2 2868B 2 2868B 2 2868B
547 HEX HEAD CAP SCREW. 21 2796GP 21 2796GP 24 2796GP 24 2796GP
554 HEX HEAD CAP SCREW. 1 2796U 1 2796U 1 2796U 1 2796U
76
Page 77
Miscellaneous Frame Components
MODEL NUMBER
ITEM DESCRIPTION VSG 1551 THRU
VSG 2101
QTY VPN
GASKET AND O-RING KIT; 1 KT710D
504 FLANGE SET 513, 514 & 547. 1 A25190C
504 FLANGE SET 513A, 514A & 547
ECON-O-MIZER PORT. 2 A25190D
512 MANIFOLD GASKET. 1 25676A
513 FLANGE OIL. 1 12477C
513A FLANGE ECON-O-MIZER.
514 FLANGE GASKET OIL. 1 11323F
514A FLANGE GASKET ECON-O-MIZER.
518 SUCTION FLANGE GASKET. 1 25199D
519 DISCHARGE FLANGE GASKET. 1 25199C
530 O-RING 2 2176J
538 PIPE PLUG 3/4” MPT. 3 2606A
540 DOWEL PIN. 2 2868K
542 PIPE PLUG 3/4” MPT. 1 13163F
545 HEX HEAD CAP SCREW FOR
OIL SUPPLY FLANGE. 4 11397E
NOTE: *Not pictured
**For VSS 1801 Serial Numbers 819, 820 & 821 only.
77
Page 78
Replacement Tools
291
1551
78
Page 79
Replacement Tools
MODEL NUMBER
ITEM DESCRIPTION VSSG 291 thru
VSSG 601
QTY VPN
900 GATEROTOR TOOLS (901, 910, 911,
912, 913, 914, 915, 916 & 917). 1 A25205B
901 GATEROTOR STABILIZER SET
(901A, 901B & 901C). 1 A25698A
MODEL NUMBER
ITEM DESCRIPTION VSG 751 VSG 901 VSG 1051 VSG 1201
QTY VPN QTY VPN QTY VPN QTY VPN
900 GATEROTOR TOOLS (901, 910, 911,
912, 913, 914, 915, 916 & 917). 1 A25205C 1 A25205C 1 A25205C 1 A25205C
901 GATEROTOR STABILIZER SET
(901A, 901B & 901C). 1 A25698A 1 A25698A 1 A25698A 1 A25698A
79
Page 80
Replacement Tools
MODEL NUMBER
ITEM DESCRIPTION VSG 1551 thru
VSG 2101
QTY VPN
900 GATEROTOR TOOLS (901, 910, 911,
912, 913, 914, 915, 916 & 917). 1 A25205E
901 GATEROTOR STABILIZER SET
(901A, 901B, 901C & 901D). 1 A25699A
80
Page 81
VSG 301-701 Replacement Parts Section
Recommended
Spare Parts List
Refer to the Custom Manual
Spare Parts Section for Specic Applications
Please have your Model # and Sales Order # available when ordering.
These are found on the compressor’s Name Plate.
81
Page 82
Gaterotor Assembly
82
Page 83
Gaterotor Assembly
Part totals indicated are for one gate rotor assembly, machines with two gate rotors will require
double the components listed below.
MODEL NUMBER
ITEM DESCRIPTION VSG 301 VSG 361 VSG 401
QTY VPN QTY VPN QTY VPN
100 SUPPORT ASSEMBLY 110 & 135B. 1 A25222AB 1 A25222AA 1 A25222AC
101 GATE ROTOR & DAMPER ASSEMBLY
111,120. 1 A25160AB 1 A25160AA A25160AC
102 GATE ROTOR SUPPORT ASSEMBLY
100, 101, 119 & 130. 1 A25161AB 1 A25161AA A25161AC
SHIM PACK SET (2) 121, (2) 122,
(1) 123, (1) 124. 1 A25165A 1 A25165A A25165A
110 SUPPORT. 1 25723D 1 25723C 1 25723B
111 GATE ROTOR. 1 25718B 1 25718C 1 25718D
114 SNAP RING. 1 2867L 1 2867L 1 2867L
115 RETAINER BALL BEARING 1 25935A 1 25935A 1 25935A
118 GATE ROTOR COVER GASKET. 1 25259B 1 25259B 1 25259B
119 WASHER WAVE SPRING. 1 3203A 1 3203A 1 3203A
120 DAMPER. 1 25760A 1 25760A 1 25760A
121* SHIM 0.002”. ar 25921AA ar 25921AA ar 25921AA
122* SHIM 0.003”. ar 25921AB ar 25921AB ar 25921AB
123* SHIM 0.005”. ar 25921AC ar 25921AC ar 25921AC
124* SHIM 0.010”. ar 25921AD ar 25921AD ar 25921AD
125 ROLLER BEARING. 1 2864F 1 2864F 1 2864F
126 BALL BEARING. 2 2865L 2 2865L 2 2865L
130 RETAINING RING. 1 2866H 1 2866H 1 2866H
131 RETAINING RING. 1 2867S 1 2867S 1 2867S
132 RETAINING RING. 1 2866J 1 2866J 1 2866J
135 DOWEL PIN 1 25910A 1 25910A 1 25910A
141 O-RING ROLLER BRG HSG. 1 2176L 1 2176L 1 2176L
143 O-RING BALL BRG SUPPORT. 1 2176F 1 2176F 1 2176F
155 SHIM ar 25977D ar 25977D ar 25977D
156 SHIM ar 25977C ar 25977C ar 25977C
ar = As required
83
Page 84
Gaterotor Assembly
Part totals indicated are for one gate rotor assembly, dual gate machines will require double the components.
MODEL NUMBER
ITEM DESCRIPTION VSG 501 VSG 601 VSG 701
QTY VPN QTY VPN QTY VPN
100 SUPPORT ASSEMBLY 110 & 135B. 1 A26011BB 1 A26011BA 1 A26011BA
101 GATE ROTOR & DAMPER ASSEMBLY
111,120. 1 A26002BB 1 A26002BA 1 A26002BC
102 GATE ROTOR SUPPORT ASSEMBLY
100, 101, 119 & 130. 1 A26003BB 1 A26003BA 1 A26003BC
SHIM PACK SET (2) 121, (2) 122,
(1) 123, (1) 124. 1 A26035B 1 A26035B 1 A26035B
110 SUPPORT. 1 26030BB 1 26030BA 1 26030BA
111 GATE ROTOR. 1 26032A 1 26031A 1 26033A
114 SNAP RING. 1 2867U 1 2867U 1 2867U
115 RETAINER BALL BEARING 1 25935B 1 25935B 1 25935B
118 GATE ROTOR COVER GASKET. 1 25259C 1 25259C 1 25259C
119 WASHER. 1 25007A 1 25007A 1 25007A
120 DAMPER. 1 25760A 1 25760A 1 25760A
121* SHIM 0.002”. ar 26027AA ar 26027AA ar 26027AA
122* SHIM 0.003”. ar 26027AB ar 26027AB ar 26027AB
123* SHIM 0.005”. ar 26027AC ar 26027AC ar 26027AC
124* SHIM 0.010”. ar 26027AD ar 26027AD ar 26027AD
125 ROLLER BEARING. 1 2864B 1 2864B 1 2864B
126 BALL BEARING. 1 2865B 1 2865B 1 2865B
130 RETAINING RING. 1 2866A 1 2866A 1 2866A
131 RETAINING RING. 1 2867A 1 2867A 1 2867A
132 RETAINING RING. 1 2866K 1 2866K 1 2866K
135 DOWEL PIN 1 25910A 1 25910A 1 25910A
141 O-RING ROLLER BRG HSG. 1 2176M 1 2176M 1 2176M
143 O-RING BALL BRG SUPPORT. 1 2176R 1 2176R 1 2176R
155 SHIM ar 25977G ar 25977G ar 25977G
156 SHIM ar 25977H ar 25977H ar 25977H
NOTE: * Not pictured
ar = As Required
84
Page 85
Shaft Seal
MODEL NUMBER
ITEM DESCRIPTION ALL VSG 301-401 ALL VSG 501-701
QTY VPN QTY VPN
* SHAFT SEAL KIT Viton Kit
219, 230, & 260. 1 KT709DG 1 KT709AG
219 SHAFT SEAL. 1 A 1 A
230 OIL SEAL. 1 2930C 1 25040A
244- TEFLON SEAL 1 25939A 1 25939A
252- RETAINER RING 1 2928M 1 2928M
260 O-RING 1 2176U 1 2176F
261 O-RING. (205 Only) 1 2176AE n/a
NOTE * Not pictured.
A Sold only as kit.
- See recommended spare parts lists for complete assembly.
85
Page 86
Main Rotor, Slide Valve Cross Shafts & End Plate
Models VSG301-401 Counter Clockwise ONLY
86
Page 87
Main Rotor, Slide Valve Cross Shafts & End Plate
Models VSG301-401 Counter Clockwise ONLY
MODEL NUMBER
ITEM DESCRIPTION VSG 301 VSG 361 VSG 401
QTY VPN QTY VPN QTY VPN
201 MAIN ROTOR ASSEMBLY. 1 A25226AB 1 A25226AA 1 A25226AC
203 OIL BAFFLE ASSEMBLY (1)
217, (1) 244, (1) 248, (1) 249, (1) 252. 1 A25942AA 1 A25942AA 1 A25942AA
SHIM ASSORTMENT (2) 240,
(2) 241, (1) 242, (1) 243 1 A25177A 1 A25177A 1 A25177A
217 OIL BAFFLE PLATE . 1 25938A 1 25938A 1 25938A
220 END PLATE. 1 25719D 1 25719D 1 25719D
221 SHAFT. 2 25941A 2 25941A 2 25941A
222 GEAR. 4 25027A 4 25027A 4 25027A
227 CLAMP. 4 25913A 4 25913A 4 25913A
228 SPACER. 4 25847A 4 25847A 4 25847A
240 SHIM 0.002” A 25409AA A 25409AA A 25409AA
241 SHIM 0.003” A 25409AB A 25409AB A 25409AB
242 SHIM 0.005” A 25409AC A 25409AC A 25409AC
243 SHIM 0.010” A 25409AD A 25409AD A 25409AD
244 TEFLON RING. 1 25939A 1 25939A 1 25939A
248 CHECK VALVE. 1 3120A 1 3120A 1 3120A
249 CHECK VALVE. 1 3120B 1 3120B 1 3120B
252 RETAINING RING 1 2829M 1 2829M 1 2829M
268 EXPANSION PIN. 4 1193D 4 1193D 4 1193D
269 EXPANSION PIN. 4 2981AA 4 2981AA 4 2981AA
271** PLUG SOLID 1 25422A 1 25422A 1 25422A
281 HEX HEAD CAP SCREW. 6 2796N 6 2796N 6 2796N
286 SOCKET HEAD CAP SCREW. 8 2795F 8 2795F 8 2795F
297 SET SCREW. 2 2060J 2 2060J 2 2060J
298 SET SCREW. 2 2060H 2 2060H 2 2060H
NOTE: * Not pictured.
** Required at top locate single gaterotor only.
A As required.
87
Page 88
Main Rotor, Slide Valve Cross Shafts & End Plate
Models VSG501-701 Clockwise ONLY
88
Page 89
Main Rotor, Slide Valve Cross Shafts & End Plate
Models VSG501-701 Clockwise ONLY
MODEL NUMBER
ITEM DESCRIPTION VSG 501 VSG 601 VSG 701
QTY VPN QTY VPN QTY VPN
201 MAIN ROTOR ASSEMBLY. 1 A26010BB 1 A26010BA 1 A26010BC
203 OIL BAFFLE ASSEMBLY (1) 217,
(1) 244, (1) 248, (1) 249, (1) 252. 1 A26034B 1 A26034B 1 A26034B
SHIM ASSORTMENT (2) 240,
(2) 241, (1) 242, (1) 243 1 A25177B 1 A25177B 1 A25177B
220 END PLATE. 1 26025B 1 26025B 1 26025B
221 SHAFT. 2 25843A 2 25843A 2 25843A
222 GEAR. 4 25027A 4 25027A 4 25027A
228 SPACER. 4 25847A 4 25847A 4 25847A
240 SHIM 0.002” A 25255AA A 25255AA A 25255AA
241 SHIM 0.003” A 25255AB A 25255AB A 25255AB
242 SHIM 0.005” A 25255AC A 25255AC A 25255AC
243 SHIM 0.010” A 25255AD A 25255AD A 25255AD
244 TEFLON RING. 1 25929B 1 25929B 1 25929B
248 CHECK VALVE. 1 3120A 1 3120A 1 3120A
249 CHECK VALVE. 1 3120B 1 3120B 1 3120B
252 RETAINING RING 1 2928N 1 2928N 1 2928N
255 WASHER 2 25977E 2 25977E 2 25977E
256 WASHER 2 25977F 2 25977F 2 25977F
268 EXPANSION PIN. 4 1193D 4 1193D 4 1193D
269 EXPANSION PIN. 4 2981AA 4 2981AA 4 2981AA
281 HEX HEAD CAP SCREW. 8 2796B 8 2796B 8 2796B
282 SOCKET HEAD CAP SCREW 2 2795D 2 2795D 2 2795D
297 SET SCREW. 2 2060J 2 2060J 2 2060J
298 SET SCREW. 2 2060H 2 2060H 2 2060H
NOTE: * Not pictured.
A As required.
89
Page 90
Slide Valve Carriage Assembly
Volume Ratio
Capacity Slide
Assembly Includes Carriage and Slides.
Carriage Assembly
90
Page 91
Slide Valve Carriage Assembly
MODEL NUMBER
ITEM DESCRIPTION ALL VSG 301-401 ALL VSG 501-701
QTY VPN QTY VPN
300 CARRIAGE ASSEMBLY. 1 A25179A 1 A26012B
304 CAPACITY PISTON 340, 341, 350 & 355. 1 A25183A 1 A25183B
305 VOLUME PISTON 340, 342, 350 & 355. 1 A25184A 1 A25184B
316 CAPACITY RACK. 1 25023D 1 25024A
318 CAPACITY RACK SHAFT. 1 25772C 1 25772A
323 VOLUME RATIO RACK. 1 25023C 1 25023A
325 VOLUME RATIO RACK SHAFT. 1 25772D 1 25772B
350 PISTON RING SET. 2 2953AE 2 2953AA
360 LOCK WASHER (PAIR). 2 3004C 2 3004C
361 WASHER. 2 13265B 2 13265B
363 NUT. 4 2797A 4 2797A
372* SOCKET HEAD CAP SCREW. N/A 1 2795M
Notes:There are two slide valve carriages per compressor. Each one each has its
own Volume Ratio and Capacity slide valves. The above totals are per side of the
compressor, double the quantities if both slide valve carriages are being worked
on.
*.Not Pictured.
91
Page 92
Actuator & Command Shaft
92
Page 93
Actuator & Command Shaft
MODEL NUMBER
VSSG 291 thru VSG 751 thru VSG 1051 thru VSG 1551 thru
ITEM DESCRIPTION VSSG 601 VSSG 901 VSG 1201 VSG 2101
QTY VPN VPN VPN VPN
400 COMMAND SHAFT ASSEMBLY 2 A25994B A25994C A25994D A25994E
401 SLIDEVALVE ACUATOR 2 25972D 25972D 25972D 25972D
446 O-RING 2 2176X 2176X 2176X 2176X
93
Page 94
Miscellaneous Frame Components
Model VSG 301-401
Model VSG 501-701
94
Page 95
Miscellaneous Frame Components
MODEL NUMBER
ITEM DESCRIPTION ALL VSG 301-401 ALL VSG 501 - 701
QTY VPN QTY VPN
512 MANIFOLD GASKET. 1 25737A 1 26037A
514 ECON-O-MIZER GASKET. 2 11323GG 2 11323D
522 COUPLING LOCK PLATE n/a 1 25004D
523 LOCK WASHER n/a 1 3004H
528 ECON-O-MIZER PLUG. 2 25419A 2 25397K
530 O-RING n/a 2 2176BF
540 DOWEL PIN 2 2868B 2 2868B
542 PIPE PLUG 3 2606C 10 2606B
551 HEX HEAD CAP SCREW n/a 2 2796C
570 BEARING OIL PLUG 1 25978A n/a
571 PLUG 1 25979A n/a
572 SPRING 1 3148A n/a
Notes*. Not Pictured.
95
Page 96
Miscellaneous Frame Components
Housing Accessories
96
Page 97
Miscellaneous Frame Components
Housing Accessories
MODEL NUMBER
ITEM DESCRIPTION VSG 301 - 701
QTY VPN
117 GATE ROTOR COVER. 1 25416B
118 COVER GASKET. 2 25259B
129 GASKET. 1 11323T
180 INLET SCREEN. 1 25920A
343 PISTON COVER. * 1 25724B
MODEL NUMBER
ITEM DESCRIPTION VSG 301 - 401 VSG 501 - 701
QTY VPN QTY VPN
345 O-RING. 4 2176BX 4 2176CA
346 O-RING. 2 2176BG 2 2176BG
97
Page 98
Replacement Tools
MODEL NUMBER
ITEM DESCRIPTION ALL VSG 301-401 ALL VSG 501-701
QTY VPN QTY VPN
901 GATEROTOR STABILIZER. 1 25742A 1 25742B
902 SEAL INSTALLATION TOOL 1 25455A 1 25455B
98
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99
Page 100
EmersonClimate.com
Vilter Manufacturing LLC
P.O. Box 8904
Cudahy, WI. 53110-8904
P: 414-744-0111
F: 414-744-1769
www.vilter.com
(1/2011) Emerson and Vilter are trademarks of Emerson Electric Co. or one of its affiliated companies.
100
©2011 Emerson Climate Technoligies, Inc. All rights reserved. Printed in the USA.
35391SB Rev. 06
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