Corken D Series Instruction manual

Model FT891
Compressor
Model FD891
Compressor
Model D791
Compressor
Installation, Operation
& Maintenance Manual
D and T-Style Double-Acting Gas Compressors
All Models 791 and 891
Warning: (1) Periodic inspection and maintenance of Corken products is essential. (2) Inspection, maintenance and installation of Corken products must be made only
by experienced, trained and qualified personnel. (3) Maintenance, use and installation of Corken products must comply with Corken instructions, applicable laws and
safety standards. (4) Transfer of toxic, dangerous, flammable or explosive substances using Corken products is at user’s risk and equipment should be operated only
by qualified personnel according to applicable laws and safety standards.
ORIGINAL INSTRUCTIONS IJ110H
Solutions beyond products...

Warning
Install, use and maintain this equipment according to Corken’s instructions and all applicable federal, state, local laws
and codes. Periodic inspection and maintenance is essential.
Corken One Year Warranty
CORKEN warrants that its products will be free from defects in material and workmanship for a period of one year
from date of installation, provided that the warranty shall not extend beyond twenty-four (24) months from the date of
shipment from CORKEN. If a warranty dispute occurs, the DISTRIBUTOR may be required to provide CORKEN with
proof of date of sale. The minimum requirement would be a copy of the DISTRIBUTOR’S invoice to the customer.
CORKEN products which fail within the warrant period due to defects in material or workmanship will be repaired or
replaced at CORKEN’s option, when returned, freight prepaid to CORKEN, 9201 North I-35 Service Road, Oklahoma
City, OK. 73131.
Parts subject to wear or abuse, such as mechanical seals, blades, piston rings, valves and packing, and other parts
showing signs of abuse, neglect or failure to be properly maintained are not covered by this limited warranty. Also,
equipment, parts and accessories not manufactured by CORKEN but furnished with CORKEN products are not
covered by this limited warranty and the purchaser must look to the original manufacturer’s warranty, if any. This
limited warranty is void if the CORKEN product has been altered or repaired without the consent of CORKEN.
All implied warranties, including any implied warranty of merchantability or fitness for a particular purpose, are expressly
negated to the extent permitted by law and shall in no event extend beyond the expressed warrantee period.
CORKEN DISCLAIMS ANY LIABILITY FOR CONSEQUENTIAL DAMAGES DUE TO BREACH OF ANY WRITTEN OR
IMPLIED WARRANTY ON CORKEN PRODUCTS. Transfer of toxic, dangerous, flammable or explosive substances
using CORKEN products is at the user’s risk. Experienced, trained personnel in compliance with governmental and
industrial safety standards should handle such substances.
Important notes relating to the European Union (EU) Machinery Directive
Compressors delivered without electric motors are not considered as machines in the EU Machinery Directive. To
ensure EU compliance, the compressor should be ordered with the optional 3022-1X Declaration of Conformity. The
fabricator of the machinery must assure and declare full compliance with this Directive before the machine in which
the compressor will be incorporated, or of which it is a part, is put into service.
Contacting the Factory
Before contacting the factory, note the model and serial numbers. The serial number directs Corken personnel to a
file containing all information on material specifications and test data applying to the product. When ordering parts,
the Corken service manual or Installation, Operations, and Maintenance (IOM) manual should be consulted for the
proper part numbers. ALWAYS INCLUDE THE MODEL NUMBER AND SERIAL NUMBER WHEN ORDERING PARTS.
The model and serial numbers are shown on the nameplate of the unit. Record this information for future reference.
Model No.
Serial No.
Date Purchased
Date Installed
Purchased From
Installed By
2

Table of Contents
Chapter 1—Features and Benefits ...............................................................4
Chapter 2—Installation ........................................................................5
2.1 Location .................................................................................5
2.2 Foundation ...............................................................................5
2.3 Piping ...................................................................................5
2.4 Liquid Trap ...............................................................................6
2.5 Driver Installation and Flywheels ..............................................................7
2.6. Crankcase Lubrication .....................................................................7
2.7 Purging, Padding, Venting, and Draining of Distance Pieces .......................................11
2.8 Relief Valves .............................................................................12
2.9 Shutdown and Alarm Devices ...............................................................12
Chapter 3—Start Up ..........................................................................12
3.1 Inspection After Extended Storage ...........................................................12
3.2 Flywheel and V-belt Alignment ..............................................................12
3.3 Crankcase Oil Pressure Adjustment ..........................................................13
3.4 Startup Check List ........................................................................14
Chapter 4—Routine Maintenance Chart .........................................................15
Chapter 5—Service Procedures ................................................................15
5.1 Valve s ..................................................................................15
5.2 Heads/Cylinder Cap ......................................................................16
5.3 Piston Rings and Piston Ring Expanders ......................................................16
5.4 Piston Replacement.......................................................................17
5.5 Piston Rod Packing Adjustment .............................................................17
5.6 Cylinder and Packing Replacement ..........................................................17
5.7 Bearing Replacement for Crankcase and Connecting Rod ........................................20
5.8 Oil Pump Inspection ......................................................................22
5.9 Gasket Sets .............................................................................23
Appendices
A. Model Number Identification Code and Available Options..........................................24
B. Specifications ............................................................................28
C. Outline Dimensions ........................................................................30
D. Parts Details .............................................................................34
E. Troubleshooting ...........................................................................50
F. Extended Storage Procedures................................................................51
3

Chapter 1—Features and Benefits
High-efficiency PEEK valves:
Offer quiet operation and increase durability in
process gas applications.
Ductile iron construction:
Maximum thermal shock endurance for cylinder
and head.
Self-lubricating PTFE piston rings:
Multiple material options provide the most
cost-effective operation of compressors for
non-lube service. The step-cut design
maximizes performance throughout the life of
the piston ring.
Positively locked pistons:
Simple piston design allows end clearance to be
precisely set to provide maximum efficiency and
long life.
Self-lubricating piston rod seals:
Seals constructed of PTFE incorporating special
fillers to minimize oil carry over and leakage.
Spring loaded seal design self adjusts to
compensate for normal wear.
Nitride-coated piston rods:
Impregnated nitride coating provides superior
corrosion and wear resistance.
Adjustable packing screw:
Ensures maximum sealing capacity during the
life of the packing (T791 and T891 models only).
Cast iron crossheads:
Durable cast iron crossheads provide
superior resistance to corrosion
and galling.
Pressure-lubricated crankcase with filter:
Self-reversing oil pump ensures proper
lubrication regardless of directional rotation
to main bearing and connecting rod bearings.
Standard 10-micron filter ensures long-lasting
bearing life.
Lower packing (V-ring)
Middle packing (V-ring)
Upper packing
(Segmented)
Upper distance piece
Lower distance piece
Construction details: Model FT891 compressor
Oil deflector ring
4

Chapter 2—Installation
2.1 Location
NOTE: Compressor must be installed in a well
ventilated area.
Corken’s compressors are designed for outdoor duty.
Consult the factory before installing a compressor in
extreme conditions such as corrosive environments and
arctic conditions for extended periods of time. Always
review the local safety regulations and building codes
and ensure the installation meets all local safety and
building standards.
Since Corken’s compressors typically handle toxic and
flammable gases, they should be located outdoors in
a well ventilated area. To ensure the compressor is
accessible from all sides and has unrestricted air flow
for adequate cooling, a minimum of 18 inches (45 cm)
clearance between the compressor and the nearest wall
is recommended.
Noise:
Many factors affect the noise level generated by a
compressor installation. Several of these, including
motor noise, piping vibration, foundation/skid design,
and surrounding structures are outside Corken’s control.
The use of sufficient pipe supports, flexible hoses, and
proper baseplate/skid support will all reduce noise. Thus,
Corken cannot guarantee a particular noise level from
our compressors. However, noise levels from a properly
installed Corken compressor typically do not exceed 85
dBa at three feet (0.91 meters).
2.2 Foundation
A proper foundation is essential for a smooth running
compression system. The compressor should be
mounted to a structural steel skid that is attached to a
concrete slab. The slab must be at least eight inches
thick with a two inch skirt around the circumference of
the structural steel skid. The structural steel skid should
be securely anchored into the foundation by 3/4 inch
diameter by eight inch long “J” bolts. The total mass of
the foundation should be approximately twice the weight
of the compressor system (compressor, structural steel
skid, motor, etc.). See figure 2.2 for details.
Main beam (C-beam or W-beam)
Cross beam (H-beam)
3/4" diameter “J” bolt
Hex nut
and washer
Concrete foundation
Ground level
Proper Foundation Design
Figure 2.2: Recommended foundation details for Corken compressors.
NOTE: For a more detailed explanation of a proper
foundation design, please refer to item number ED410
(Important Instructions for Compressor Foundation Design).
2.3 Piping
A proper piping design is as important as a proper foundation
when it comes to a smooth operating compressor. A
poorly designed piping system results in an undesirable
transmission of compressor vibration to the piping. For best
results follow the recommendations below.
DO NOT SUPPORT PIPING WITH THE COMPRESSOR.
Unsupported piping is the most frequent cause of
vibration. To minimize the transmission of vibration from
the compressor to the piping, install flexible connectors
vertically as shown below (see figure 2.3 for details).
Concrete
foundation
Steel
structural skid
Pipe
support
Flexible
connections
Flexible
connections
Ground level
Figure 2.3: Flexible connectors should be used to minimize
transmission of vibration to the piping.
To prevent excessive pressure drop between the suction
source and the compressor and the final discharge point
and the compressor, the piping must be adequately
5

sized. In most cases, piping should be at least the same
diameter as the suction nozzle on the compressor.
If a restrictive device such as a valve, pressure regulator,
or back-check valve is to be installed in the compressor’s
suction line, care must be taken. The suction line volume
between the restrictive device and the compressor
suction nozzle must be at least ten times the swept
cylinder volume.
On liquefied gas applications, a liquid trap must be
installed on the inlet side of the compressor. This prevents
liquid from entering the compressor (see section 2.4).
It is of equal importance to protect the discharge side of
the compressor from liquid entry. Always install a check
valve on the discharge side of the compressor and use
a piping design that does not allow liquid to gravity drain
into the compressor.
For vapor recovery applications, be certain to install
a check valve on vapor lines discharging to the liquid
space of the tank.
All piping must be in accordance with the laws and codes
governing the service. In the United States, the following
codes apply:
For LP Gas—The National Fire Protection Association
Pamphlet No. 58, Standard for the Storage and Handling
of Liquefied Petroleum Gases.
For Ammonia—The American National Standards
Institute, Inc., K61.1-1999, Storage and Handling of
Anhydrous Ammonia.
Copies of these are available from NFPA, 60 Baterymarch
Street, Boston, Mass, 02110 and ANSI, 1430 Broadway,
New York, N.Y., 10018. Install, use, and maintain this
equipment according to Corken’s instructions and all
applicable federal, state, and local laws and previously
mentioned codes. Other laws may apply in different
industries and applications.
2.4 Liquid Trap
Compressors pressurize gas and are not designed to
pump liquids. The entry of even a small amount of liquid
into the compressor results in serious damage.
On liquefied gas applications, a liquid trap must be used
to prevent liquid from entering the compressor.
Corken’s liquid trap is ASME code stamped and provides
the most thorough liquid separation (see figure 2.4).
It contains two level switches, one for alarm and one
for shutdown. In some cases the alarm switch is used
to activate a dump valve (not included with trap) or
sound an alarm so the trap can be manually drained
by the operator. It also contains a mist pad; a mesh of
interwoven wire designed to remove fine liquid mists. The
ASME code trap comes standard on Corken’s 107B and
109B mountings.
NOTE: Before grounding any welding devices to the
trap or associated piping, the LIQUID LEVEL SWITCH
MUST BE REMOVED from the trap. Failure to do so will
damage the contacts of the switch.
Figure 2.4: ASME automatic liquid trap
Relief valve
Pressure gauge
Inlet
Shutdown switch
Liquid level alarm switch
Drain valve
Class 300 RF flange code-stamped automatic
liquid trap with two NEMA 7 liquid-level switches for
compressor shutdown and alarm. Equipped with relief
valve, pressure gauge, demister pad, and drain valve.
Process Connection Sizes:
• 2" x 2" Class 300 RF flange
6

If the compressor is equipped with a liquid trap not
manufactured by Corken, make sure it is adequately
sized to remove the liquid entrained in the suction stream.
2.5 Driver Installation and Flywheels
Corken’s vertical compressors can be driven by electric
motors or combustion engines (gasoline, diesel, natural
gas, etc.). A proper driver selection should turn the
compressor between 400 and 825 RPM.
NOTE: Never operate a reciprocating compressor without
a flywheel. Severe torsional imbalances will result causing
vibration and an unusually high horsepower requirement. The
flywheel should never be replaced by another pulley unless it
is equal to or higher than the wk2 value of the flywheel.
Humid climates can cause problems with explosion
proof motors. The normal breathing of the motor and
alternating temperatures—warm when running and cool
when stopped—can drawn moist air into the motor.
As the moist air condenses, it can build up and cause
motor failure. To prevent this, make a practice of running
the motor at least once a week on a bright, dry, day for
an hour or so without the V-belts attached. During this
period of time, the motor will heat up and vaporize the
condensed moisture. NOTE: No motor manufacturer
guarantees an explosion proof or totally enclosed (TEFC)
motor against damage from moisture.
When installing an engine driver, carefully review the
instructions from the manufacturer and ensure the
engine is properly installed.
2.6. Crankcase Lubrication
The crankcase was drained before shipment. Before
starting the machine, fill the crankcase to the full mark
on the oil bayonet and not above. To ensure proper
lubrication of the crankcase parts, the crankcase should
be filled through the crankcase inspection plate (see
figure 5.5 for the proper oil filling location).
Compressor
Model
Approximate
Quarts Capacity Liters
791, 891 7.0 6.6
Figure 2.6A: Oil capacity chart.
General Notes on Crankcase Oil
Corken gas compressors handle a wide variety of
gases in a multitude of operating conditions. They
are used in all areas of the world from hot dusty
deserts, to humid coastal areas, to cold arctic climates.
Some compressors may be lightly loaded and run
only occasionally, while others may be heavily loaded
and operate 24/7. Thus, no single crankcase oil or
maintenance schedule is right for every compressor.
Availability of brands and grades of oil can vary from
one location to another. These factors can make it
challenging for a Corken compressor user to select a
suitable crankcase oil. This guide is intended to aid in
that regard.
It is safe to say that purchasing a quality crankcase oil,
and changing it regularly, is significantly less costly than
the repair bill and downtime associated with a lubrication
failure in any gas compressor. Considering the relatively
small volume of oil used in Corken compressors, and the
critical nature of the services where these compressors
are used, selecting the appropriate high quality oil is
the most economical choice. It will help ensure the
dependability and longevity of the compressor.
Corken recommends using industrial oils (rather than engine
oil or “motor oil”). Industrial oils have additives selected
and blended for specific purposes. Many are designed
specifically for the challenges inherent in compressor
crankcases. Industrial oils are available as a conventional
(mineral based) oil, a synthetic oil, or a blend of the two.
All new Corken compressors are tested at the factory
using a conventional mineral oil. This oil is drained
prior to shipment. An oil suitable for the anticipated
environmental and operating conditions must be selected
and added to the compressor prior to the initial startup.
Oils to Avoid
Selecting a crankcase oil based on low price or easy
availability is seldom the most economic decision.
Following are oils to avoid.
• Do not use any oil with a viscosity index below 95.
• Do not use any oil with a pour point less than 20°F
(11°C) lower than the anticipated minimum ambient
temperature (unless a crankcase oil heater is used).
• Do not use engine/motor oil.
See below for additional detail on each of these
parameters.
Critical Oil Characteristics
Viscosity
Viscosity is the most important physical property of
lubricating oil. Simply put, the viscosity of an oil is a
measure of its resistance to flow. In gas compressors,
oils with higher viscosity (like ISO 100) are thicker and
are used for higher ambient temperatures. Oils with lower
viscosity (like ISO 68) are thinner and are used at lower
ambient temperatures. If the oil’s viscosity is too high, the
oil may not circulate through the compressor adequately.
If the viscosity is too low, the lubricating film will be
unable to protect the components from wear.
7

Viscosity Index
Viscosity Index (VI) is a measure of how much the
oil’s viscosity changes as its temperature changes. A
low viscosity index is an indication that the viscosity
changes more as the temperature changes. Oils with low
viscosity index tend to become thin as the oil temperature
increases. This can cause lubrication failure as well as
unstable oil pressure. A high viscosity index reflects
a more stable viscosity, and is generally preferred for
Corken compressors. The minimum Viscosity Index for
oils used in Corken compressors is 95 (VI is a unit-less
number). This is particularly important when operating
at high or low temperature extremes, or at a variety of
ambient temperatures (seasonal changes). Oils with a high
viscosity index can be used at wider ambient temperature
range compared to oils with a lower viscosity index.
It should be noted that a conventional oil (not synthetic)
with a high viscosity index may not necessarily be
suitable for continuous service at high temperature.
Such an oil will oxidize faster than a synthetic oil.
Synthetics have naturally high viscosity index, and are
therefore recommended for “heavy service” as described
below—including high temperature and continuous duty
applications. It many climates, the use of the correct
synthetic oil will eliminate the need to change oil viscosity
grades as the seasons change.
Pour Point
The pour point of an oil is the lowest temperature at
which the oil flows. At temperatures below the pour
point, the oil is essentially solid and can’t freely flow to
the compressor’s bearings and other wear surfaces, or
even to the compressor’s oil pump.
The oil’s pour point is particularly critical when starting
a compressor at low temperature conditions. An oil
should have a pour point at least 20°F (11°C) below the
lowest expected ambient temperature. For example,
if the minimum ambient temperature is expected to
Crankcase Oil Recommendations (Except Ammonia Service)
Normal Service
Ambient Temperature 1 Oil Product Oil Type 2 Viscosity ISO 3 Viscosity Index 3 Pour Point 3
40 to 100°F (4 to 38°C) Mobil DTE 10 Excel 100 C100 127 -27°F (-33°C)
Mobil Rarus 427 C100 100 16°F (-9°C)
Phillips 66 Gas Compressor Oil C100 102 -20°F (-29°C)
Chevron Regal R&O C100 97 5°F (-15°C)
Sunoco Sunvis 900 C100 95 -15°F (-26°C)
10 to 65°F (-12 to 18°C) Mobil DTE 10 Excel 68 C68 156 -38°F (-39°C)
Mobil DTE Heavy Medium C68 95 5°F (-15°C)
Phillips 66 Premium Gas Compressor Oil B68 133 -27°F (-33°C)
Chevron Regal R&O C68 99 -11° F (-24°C)
Sunoco Sunvis 900 C68 104 -21°F (-29°C)
Heavy Service
10 to 100°F (-12 to 38°C) Mobil SHC 627 4 S100 162 -49°F (-45°C)
Royal Purple Synfilm NGL 100 S100 130 -44°F (-42°C)
Dyna-Plex 21C Synzol CO ISO 100 S100 132 -49°F (-45°C)
-20 to 90°F (-29 to 32°C) Mobil SHC 626 4 S68 165 -59°F (-51°C)
Royal Purple Synfilm NGL 68 S68 132 -76°F (-60°C)
Crankcase Oil Recommendations (Ammonia Service Only)
Normal Service
Ambient Temperature 1 Oil Product Oil Type 2 Viscosity ISO 3 Viscosity Index 3 Pour Point 3
40 to 100°F (4 to 38°C) Mobil Rarus 427 C100 100 16°F (-9°C)
10 to 65°F (-12 to 18°C) Phillips 66 Ammonia Compressor Oil C68 102 -27°F (-33°C)
Chevron Capella P68 C68 96 -44°F (-42°C)
Mobil Rarus 426 C68 105 16°F (-9°C)
Heavy Service
10 to 100°F (-12 to 38°C) Mobil Gargoyle Arctic SHC 228 5 S100 147 -43°F (-45°C)
Royal Purple Uni-Temp 100 S100 124 -53°F (-47°C)
-20 to 90°F (-29 to 32°C) Mobil Gargoyle Arctic SHC 226E 5 S68 136 -58°F (-50°C)
Royal Purple Uni-Temp 68 S68 118 -51°F (-46°C)
1 Consult Corken for oil recommendations in very hot climates—ambient temperatures consistently above 100°F (38°C).
2 Oil type: C=Conventional, S=Synthetic, B=Conventional/Synthetic blend
3 Information available from oil manufacturers at the time of publication.
4 Mobil SHC oils are synthetic oils which require that the crankcase be flushed of residual mineral oil.
5 Mobil Gargoyle Arctic SHC oils are synthetic oils which require that the crankcase be flushed of residual mineral oil.
Figure 2.6B: Oil selection chart.
8

be 0°F (-18°C), the pour point must be no higher than
-20°F (-29°C).
Do not assume the pour point of an oil is low enough.
Consult the oil’s technical data sheet – generally
available on the oil manufacturer’s website. Many
conventional oils have a pour point around 0 to 15°F
(-18 to -9°C) which is too high to use at low ambient
temperatures. Synthetic oils generally have a lower pour
point than conventional oils.
Crankcase Oil Recommendations
The primary factors for selecting a suitable crankcase oil
from the chart below are ambient temperature range and
the anticipated service—normal service or heavy service.
The ambient temperature determines the required oil
viscosity. Consider the full range of high and low
ambient temperatures at the compressor’s location when
selecting an oil. It may be necessary to use an ISO 100 in
summer and an ISO 68 in winter. Synthetic oils generally
have a wider ambient temperature range due to their
higher viscosity index.
For the purpose of selecting a suitable crankcase oil for
a Corken compressor, normal and heavy service are
defined below.
Normal Service
T “Normal service” can be defined as anything that is not
considered “heavy service” as described below.
Common examples of “normal service” applications:
• LPG liquid transfer (intermittent duty)
• Ammonia liquid transfer (intermittent duty)
• Most tank evacuation applications
Conventional mineral based oils have been used
successfully for many years in these services.
Heavy Service
O“Heavy Service” is defined as an application where
the compressor is subject to any one (or more) of the
following:
• Continuous duty service (several hours each day or
more)
• Compressor consistently loaded at or near its maximum
horsepower rating
• Compressor speed is at or near its maximum speed
rating
• Services with a “wet” gas such as natural gas with
high content of heavy hydrocarbons such a butane,
pentane, etc.
• Services dealing with low vapor pressure hydrocarbons
(such as butane unloading in winter) where condensation
in the gas can result in dilution of the crankcase oil
• Compressors operating at high or low temperature
extremes
Synthetic oils are recommended for “heavy” services.
Ammonia Service
Compressing ammonia presents particular challenges
from a lubrication standpoint. Never use a detergent
oil in a compressor in ammonia service. Ammonia will
react with the detergent and cause lubrication failure.
Fortunately, some oils are specifically blended for use in
ammonia compressors — though some of these are best
suited only for cooler climates.
Consult these charts or the oil manufacturer’s product
data sheet for information regarding the oil’s viscosity,
viscosity index, pour point, etc. This information is
generally available on line or from the oil supplier. Do not
use an oil if it’s critical properties can not be confirmed,
of if there is any other reason to doubt its suitability.
Contact Corken if additional assistance is needed when
selecting a crankcase oil.
Oil Change Intervals
Oil change intervals can vary significantly depending
on local environmental conditions, the gas being
compressed, and the oil being used. Unless there are
factors that shorten the life of the oil, the following
recommendations apply:
Conventional oil: 2200 hours or 6 months—whichever
comes first
Synthetic oil: 6000–8000 hours* or one year—whichever
comes first
* Oil change intervals in this range should be confirmed
via oil analysis.
Environmental or operational issues such as dirty/
dusty or humid conditions will require more frequent oil
changes. Contamination/dilution of the oil by liquids in
the gas stream can also shorten the life of the oil. Visually
check the oil level and the oil condition at least monthly
(compare to unused oil).
Indications that dictate more frequent oil changes:
• Unusually dirty or discolored oil (or unusual smell)
• Oil dilution by condensation or other liquids in the gas
stream (see below)
• Change in viscosity for any reason (various oil additives
can break down over time)
9

• Changing ambient temperature may cause the need for
a different viscosity
The oil should be changed as often as necessary to
maintain clean, undiluted oil of the proper viscosity. Each
time the oil is changed, the oil filter (Corken part number
4225) should also be changed.
Oil Analysis
The best way to determine the needed oil change
interval for any particular compressor is to have an oil
analysis conducted. Numerous labs can analyze a used
oil sample and advise its condition. After 2–3 such tests,
a determination can be made for a recommended oil
change interval for a particular compressor in its specific
environmental situation and operating conditions.
Regular oil analysis can help improve the compressor
durability and decrease oil usage by maximizing the oil
change intervals. Based on the oil analysis, the oil can be
changed when it is needed, and not changed when it is
not yet necessary.
Oil Dilution
Crankcase oil can be diluted by various products in the
gas stream. As an example, when compressing butane
in winter, the vapor pressure is very low and there can
be a lot of entrained liquid butane with the gas stream.
This liquid can collect in the compressor and dilute the
crankcase oil. This thins the oil and reduces its ability to
properly lubricate the compressor.
Hydrocarbon mixtures containing heavy hydrocarbons
such as butane, pentane, hexane, etc. often operate
at pressure above the vapor pressure of these heavier
constituents. Thus, they often produce a “wet” gas which
can dilute the crankcase oil.
Long Term Storage
When a compressor is removed from long term storage,
the oil should be changed before putting the compressor
back into service. Specifically, if it has been unused
over a season (such as over a winter), the oil should be
changed.
Crankcase Oil Heater Option
Corken offers a crankcase oil heater as an option on
all models except the small model 91. This heater is
available in 110V and 220V versions and is rated for Class
1, Division 1 and 2, Group B, C, D service. The heater
includes a thermostat set at 70°F (21.1°C). The heater
alleviates concerns about cold weather startup. When
using the heater, an ISO 100 viscosity oil will do well
regardless of low ambient temperature.
Cylinder Lubricating Oil
All Corken gas compressors are designed to operate
without cylinder lubrication. However, many Corken
Customers, particularly in the oil and gas industry, use
lubricated compressor cylinders to extend the service
life of the compressor’s valves, piston rings, and packing.
Compressor cylinders operate at higher temperatures
than the crankcase, so oils used in this service often
have a higher viscosity than the crankcase oil. A viscosity
of ISO 150 (or higher) is common for cylinder lube oil.
Several companies make oil specifically designed for
this service and many of these oils have properties that
inhibit dilution or washing away of the oil by condensates
in the process gas. These oils typically also have
properties that prevent corrosion and carbon buildup in
the cylinders and valves. Contact Corken is assistance
is needed in selecting a suitable cylinder lubricating
oil. Oil manufacturers are often a good source for this
information as well.
Engine oils (motor oils) should never be used as a
cylinder lubricant. The additives in engine oil are poorly
suited for that purpose.
Engine Oils (Motor Oils)
At noted above, engine oils (or motor oils) are
not recommended for use in Corken compressor
crankcases or cylinders. Engine oils are formulated
for use in internal combustion engines and contain
additives that specifically counter the contaminants
created by the combustion of fuel (soot, CO2, water,
etc.). As such, they are not necessarily the best oils to
use in a gas compressor.
Detergents and dispersants in engine oils can react
with the compressor’s process gas, or form emulsions
inside the compressor’s crankcase that are detrimental
to lubrication. Ultimately, this negatively effects the
oil’s properties and damages the compressor’s critical
internal components.
If a suitable industrial oil is not readily available, engine
oils can temporarily be used in Corken compressors in
normal service, but only until a suitable industrial oil can
be sourced (see above for definition of “normal service”).
Engine oils should not be used for compressors in
“heavy service”.
Engine oil is labeled with an API “donut” indicating the
API Service Grade. It is critical that the engine oil have
an API Service Grade of SJ or better. Engine oils with an
API Service Grade of SA and SB are obsolete, but still
readily available. These very low quality oils should never
be used in Corken compressors. Industrial oils do not
receive an API Service Grade like engine oil does.
10

2.7 Purging, Padding, Venting, and
Draining of Distance Pieces
With Corken’s compressor the distance piece is key to
leakage control and oil-free compression. It is integral
with the crosshead guide. The distance piece is equipped
with tapped holes for purging, padding, venting, and
draining (see Figure 2.7). Proper connections to and
from these tapped holes are essential for optimum
compressor performance.
Determining the ideal leakage control system can be
complicated. Factors to consider include the hazards
of the gas being handled, operating conditions, duty
cycle, compressor location, proximity to personnel, local
regulations, etc. Compressors installed indoors that are
handling flammable or toxic gasses should always be
properly purged. Corken’s applications engineers are
always available for assistance.
Corrosive gases should be prevented from entering the
crankcase. Even small amounts of particular gases in the
crankcase can seriously contaminate the crankcase oil.
To prevent contamination of the crankcase, the distance
piece must be purged, padded, or vented using a clean,
non-corrosive gas like dry air or nitrogen.
Upper
distance
piece
Drain plug
Lower
distance
piece
Drain plug
Figure 2.7: Distance piece details for a model FT891
Purging:
Purging the distance piece minimizes leakage of
process gas to the atmosphere. Any process gas
leaked into the distance piece is quickly diluted by the
purge gas and swept away. Depending on the type of
gas and local regulations, the purge gas should be
vented to a safe release area, flare, compressor’s inlet,
or treatment facility.
When purging, it is critical to maintain the proper
pressure loading across each set of packing. The higher
pressure should be on the open side of the “V” which is
the side with the spring.
Moisture, oil, or condensate can be removed from the
distance piece with the purge gas by using the lower
distance piece connection (drain location) as the purge
gas outlet connection.
Corken offers purge kits with the necessary regulator,
valves, fittings, etc. Consult factory for details.
Padding (Buffering):
If purging is not practical, the distance piece should
be pressurized with a static pressure. This is called
padding or buffering. Padding is done at a pressure
above the compressor’s suction pressure using a clean
noncorrosive gas like dry air or nitrogen. The higher
pressure in the distance piece tends to reduce the
process gas leakage to the atmosphere. A small amount
of purge gas will likely get into the process gas. A
pressure regulator can be used to help maintain the
proper pressure in the distance piece.
When padding, it is critical to maintain the proper
pressure loading across each set of packing. The higher
pressure should be on the open side of the “V” which is
the side with the spring.
Venting:
The distance piece can be vented to an appropriate
release area, flare, or treatment facility. This is sometimes
useful for indoor installations.
Draining:
Since some oil passes the lower packing set, the
distance piece must be drained on a regular basis to
maintain oil-free compression (see figure 2.7). Corken
recommends draining the distance piece once a week in
continuous-duty operation. Installing a drain cock to the
distance piece helps simplify the process.
Highly Corrosive Gases:
When shutting down the compressor for an extended
period of time, it should be blocked from the system
using the valves located in the suction and discharge
piping and purged with dry inert gas. This procedure
significantly lowers potential damage to the compressor
caused by corrosive gases.
11

2.8 Relief Valves
A relief valve must be installed on the discharge side
of the compressor before the first block valve. With
Corken’s 107 mountings, a relief valve should be fitted
in the piping between the compressor discharge and the
four-way valve. NOTE: Relief valves may be required at
other points in the piping system.
The material specification for the relief valve must be
compatible with the gas being compressed. Review local
codes and regulations for specific requirements related
to relief valves.
2.9 Shutdown and Alarm Devices
For many applications shutdown and alarm switches
provide worthwhile protection and may prevent serious
damage to the compression system. All electronic devices
must meet local code requirements. The shutdown and
alarm devices typically used with Corken’s compressors
are as follows:
Low Oil Pressure Switch: Shuts down the compressor
if the crankcase oil pressure falls below 15 psi due to oil
pump failure or low oil level in crankcase.
High Temperature Switch: Shuts down the compressor
if the normal discharge temperature is exceeded. This
is strongly recommended for all applications. Typically,
the set point is about 30°F (-17°C) above the normal
discharge temperature but not exceed the 250°F (121°C)
when using Buna-N or Neoprene®trim or 300°F when
using PTFE or Viton®(Neoprene and Viton are registered
trademarks of the DuPont company).
Low Suction, High Discharge Pressure Switch: Shuts
down the compressor if inlet or outlet pressures are not
within preset limits.
Vibration Switch: Shuts down the compressor if vibration
becomes excessive. Recommended for compressors
mounted on portable skids.
Chapter 3—Start Up
NOTE: Read all of this chapter, before proceeding
with the startup checklist.
3.1 Inspection After
Extended Storage
If the compressor has been out of service for an
extended period of time, make certain the cylinder bore
and valve areas are free of rust or debris of any kind. For
instructions on removing the valves and/or cylinder head,
refer to chapter five.
Drain the oil from the crankcase and remove the
nameplate and access cover on the crankcase. Inspect
the running gear for signs of rust and clean or replace
parts as necessary. Replace the access cover and fill
the crankcase with the appropriate amount of lubricant
through the opening behind the nameplate. NOTE: For
best lubrication results, do not fill the crankcase through
the access cover. Squirt oil on the crossheads and rotate
the crankshaft by hand to ensure all bearing surfaces are
coated with oil.
Rotate the compressor manually and ensure running
gear functions properly. Replace the nameplate and
proceed with the startup.
3.2 Flywheel and V-belt Alignment
Before working on the drive assembly, make sure the
electric power is disconnected. When mounting new
belts, always make sure the driver and compressor are
close enough together to avoid forcing/prying the belts
over the flywheel grooves.
Improper belt tension and/or sheave alignment can cause
vibration, excessive belt wear, and premature bearing
failure. Before operating the compressor, confirm V-belt
grooves of the flywheel and driver sheave are properly
aligned. Visual inspection often will indicate if the belts
are properly aligned, but use of a square is the best
method (See video titled “How to Align the Sheave to the
Flywheel” on Corken’s YouTube Channel).
The flywheel is mounted on the shaft via a split, tapered
hub, and three bolts (see figure 3.2A). These bolts should
be tightened in an even and progressive manner to the
specified torque values listed below. There must be a
gap between the bushing flange and the flywheel when
installation is complete. Always check the flywheel runout
before startup and readjust if it exceeds the value listed in
Appendix B.
Figure 3.2A: Flywheel installation
12

Figure 3.2B: Proper belt tension
Hub
Size
Diameter
in. (cm)
Bolt Torque
Ft-lb (N-Meter)
Set Screw Torque
Ft-lb (N-Meter)
J7.25 (18.4) 75-81 (101–110) 22 (29.8)
Scan QR Code and refer to the maintenance video titled
“How to Align the Sheave to the Flywheel and Set Proper
V-Belt Tension”.
Tighten the belts until taut which means they should
not be extremely tight. Consult your V-belt supplier for
specific tension recommendations. Over tightened belts
are can cause premature bearing failure. Refer to figure
3.2B for general guidelines.
3.3 Crankcase Oil
Pressure Adjustment
Corken’s compressors are equipped with an automatically
reversible gear type oil pump. Before starting the
compressor, check and fill the crankcase with the proper
amount of lubricating oil.
Make sure the pumping system is primed and the oil
pressure is properly adjusted. When the compressor
is first started, observe the pressure gauge on the
crankcase. If the gauge fails to indicate pressure within
30 seconds, stop the machine. Loosen the oil filter and
remove the pressure gauge. Restart the compressor and
run it until oil comes out of the opening for the pressure
gauge or around the filter. Retighten the filter and reinstall
the pressure gauge.
The oil pressure should be about 20 psi (1.4 bars)
minimum for normal service. A spring-loaded relief valve
mounted in the bearing housing opposite the flywheel
regulates the oil pressure. As shown in figure 3.3, turn the
adjusting screw clockwise to increase the oil pressure
and counterclockwise to lower it. Be sure to loosen the
adjusting screw locknut before trying to turn the screw
and retighten it after making any adjustment.
Oil lter
Breather cap
Oil pressure relief valve
and adjustment screw
Oil pressure gauge
Crankcase heater
(optional)
Figure 3.3: Oil pressure adjustment
13

3.4 Startup Check List
NOTE: Before starting the compressor, verify each
item on the list below!
Failure to do so may result in a costly (or dangerous)
mistake.
1. Become familiar with the function of all piping
associated with the compressor. You must know each
line’s purpose!
2. Make certain actual operating conditions match the
anticipated conditions.
3. Ensure line pressures are within cylinder pressure ratings.
4. Clean out all piping.
5. Ensure all distance piece openings are tubed or
plugged as needed.
6. Check all mounting shims, cylinder, and piping
supports and ensure no undue twisting forces exist on
the compressor.
7. Make certain strainer elements are in place and clean.
8. Make certain cylinder bore and valve areas are clean.
9. Check the V-belt tension and alignment or drive
alignment on direct drive units.
10. Rotate flywheel by hand and make certain there is no
wobble or play.
11. Confirm the oil level in the crankcase is correct.
12. Drain all liquid traps, separators, etc.
13. Verify proper electrical supply to the motor and panel.
14. Check all gauges and confirm a zero level reading.
15. Test piping system for leaks.
16. Purge unit of air before pressurizing with gas.
17. Carefully check for any loose connections or bolts.
18. Remove all stray objects (rags, tools, etc.) from vicinity
of the unit.
19. Confirm all valves are open or closed as required.
20.Double-check all of the items listed above.
After Starting Compressor
1. Verify and note oil pressure. Shut down and
correct any problems immediately the pressure is
not within specification.
2. Observe the noise and vibration levels and correct
immediately if excessive.
3. Confirm the RPMs are within proper compressor speed.
4. Examine entire system for gas or oil leaks.
5. Note rotation direction.
6. Check start-up voltage drop, running amperage, and
voltage at motor junction box (not at the starter).
7. Verify proper lubrication rate (lubed units only).
8. Test each shutdown device and record set points.
9. Test or confirm set point on all relief valves.
10. Check and record all temperatures, pressures, and
volumes after thirty minutes and one hour.
11. After one hour running time, tighten all head bolts, valve
holddown bolts, and baseplate bolts (see Appendix B
for torque values).
14

Chapter 4—Routine Maintenance Chart
Item to Check Daily Weekly Monthly Six Months Yearly
Crankcase oil pressure
Compressor discharge pressure
Overall visual check
Crankcase oil level
4 1
Drain liquid from accumulation points 2
Drain distance pieces
Clean cooling surfaces on compressor
and intercooler (if any)
Lubricator supply tank level (if any)
Check belts for correct tension
Inspect valve assemblies
Lubricate motor bearings in accordance
with manufacturers’ recommendations
Inspect motor starter contact points
Inspect piston rings 3
1 Change oil every 2,200 hours of operation or every 6 months, whichever occurs first. If the oil is unusually dirty, change it as often as needed
to maintain a clean oil condition. Change replacement filter 4225 with every oil change.
2 Liquid traps should be drained prior to startup.
3 Piston ring life varies greatly, depending on application, gas, and operating pressures. Consult factory for additional recommendations for
your specific application.
4 If the compressor is used daily, check your oil level on a weekly basis. Otherwise check oil level on a monthly basis.
Chapter 5—Service Procedures
CAUTION: Always relieve the pressure in the
compressor before attempting any repairs. After
servicing the compressor, it should be pressure tested
and checked for leaks at all joints and gasket surfaces.
If routine maintenance is performed as listed in chapter
four, repair service on Corken’s gas compressor is
generally limited to replacing valves or piston rings.
When it comes time to order replacement parts, be sure
to consult the part details in Appendix D for a complete
list of part numbers and descriptions.
5.1 Valves
Test the compressor valves by closing the inlet piping
valves while the unit is still running; however, do not
allow the machine to operate in this way very long. If
the inlet pressure gauge does not drop to zero almost
immediately, one or more of the valves is probably
damaged or dirty. NOTE: A faulty pressure gauge is also
possible so make sure it is in good operational order
before assuming the valves are faulty.
In most cases if a valve or gasket is leaking, it will create
more heat. On a single-stage compressor, compare
the operating temperatures of either two suction or
discharge valves and cover plates to each other. If a
valve or gasket is leaking, it will have a higher operating
temperature. NOTE: This method is not suitable for
two-stage compressors that does not have at least two
suction valves or two discharge valves per cylinder.
Each suction and/or discharge valve assembly can be
easily removed for inspection. If any part of the valve
assembly is broken, it should be replaced. See parts
details for valve assemblies in Appendix D for a complete
list of part numbers and descriptions.
If a valve is leaking due to dirt or any other foreign
material between the valve plate and seat, the valve can
be cleaned and reused. However, new valve gaskets and
O-rings should be used to ensure a proper seal.
The valve holddown assemblies in Appendix D show
the various specifications used on models 791 and
891 compressors. Since more than one suction valve
arrangement is available for each model of compressor,
it is necessary to know the complete model number
in order to identify the correct valve specification (see
example listed below).
Model number FD891JM 4P FBANSNN
Valve type = Spec 4P
15

Valve Inspection and/or Replacement
Before removing and inspecting the valves, begin by
depressurizing and purging (if necessary) the compressor.
Disassembly
1. Unscrew the valve cap and remove the O-ring.
2. Remove the valve cover plate, O-ring, and holddown
screw by removing each of the four bolts. The holddown
screw is easily removed using the special wrench
supplied with the compressor.
3. After the cover plate and O-ring have been removed,
the valve cage, valve assembly, and valve gasket can
be lifted out.
4. Inspect valves for breakage, corrosion, debris,
and scratches on the valve plate. In many cases,
valves may simply be cleaned and reinstalled. If the
valves show any damage, they should be repaired or
replaced. Replacement is usually preferred since it
always ensures a proper seal; however, repair parts are
available. If valve plates are replaced, the existing valve
seats must be lapped until they are perfectly smooth. If
more than .005 of an inch must be removed to achieve
a smooth surface, the valve should be discarded.
Replacing valve plates without relapping the seat may
cause rapid wear and leakage.
Reassembly
1. Insert the metal valve gasket into the suction and/
or discharge opening of the cylinder. The metal valve
gasket should always be replaced when a new or
repaired valve is installed.
2. Insert the repaired or new valve assembly. Make sure
each suction and discharge valve is placed in the
proper opening in the cylinder.
3. Insert the valve cage.
4. Replace the O-ring and valve cover plate. Torque the
bolts to the value listed in Appendix B.
NOTE: Make sure the holddown screw has been
removed before tightening the bolts in the cover plate.
5. To ensure the valve gasket is properly seated, insert
the holddown screw and tighten to the value listed
in Appendix B. NOTE: Gaskets and O-rings are not
normally reusable.
6. With a new O-ring, screw on the valve cap and tighten
to the value listed in Appendix B.
7. Check bolts and valve holddown screws after first
week of operation and re-torque if necessary. See
Appendix B for torque values.
5.2 Heads/Cylinder Cap
A compressor cylinder cap and cylinder head very
seldom require replacement if the compressor is properly
maintained. The primary cause of damage to a cylinder
cap or head is corrosion, entry of solid debris, or liquid into
the compression chamber. Improper storage methods can
cause corrosive damage to the cylinder cap and cylinder
head. For proper storage instructions, refer to Appendix F.
Many compressor services require removal of the cylinder
cap or cylinder head. While the compressor is disassembled,
special care should be taken to avoid damage or corrosion. If
the compressor is left open for more than a few hours, bare
metal surfaces should be coated with rust preventative oil.
When reassembling the compressor, make sure the bolts
are retightened to the torque values listed in Appendix B.
5.3 Piston Rings and Piston
Ring Expanders
Figure 5.3: Piston cap removal
Piston ring life will vary considerably from application
to application. Ring life is much longer at lower speeds
and temperatures.
1. To replace the piston rings, depressurize the
compressor and purge if necessary.
2. To gain access to the piston, remove the cylinder cap
and cylinder head.
3. Loosen the piston cap bolts and remove the piston
cap as shown in figure 5.3 by pinching two loose
bolts together.
4. Remove the lock nut and lift the piston off the end of
the piston rod.
5. After the piston is removed, the piston rings and
expanders can be easily removed and replaced.
Corken recommends replacing expanders whenever
rings are replaced. To determine if the piston rings
need to be replaced, measure the radial thickness and
compare it to the chart in Appendix B.
16

5.4 Piston Replacement
1. To replace the pistons, depressurize the compressor
and purge if necessary.
2. Remove the cylinder cap and cylinder head (see
section 5.2).
3. Remove the piston cap by loosening and removing the
socket head bolts holding the piston cap to the piston
(see figure 5.3).
4. Next, remove the lock nut and lift the piston off the end
of the piston rod.
5. Check the thrust washer and shims for damage and
replace if necessary.
6. Before installing the new piston, measure the thickness
of the existing shims.
7. Reinstall the piston with new piston rings and expanders
using the same thickness of shims as before and tighten
the lock nut to the torque value listed in Appendix B.
8. For this step please refer to the section labeled
Piston Clearance (Cold) listed in Appendix D—Piston
Assembly Details. Next, remove a lower valve and
measure dimension Y at the bottom of the piston as
shown in Appendix D. If the measurement does not
fall between the minimum and maximum tolerances,
adjust the shims as necessary and confirm dimension
Y is within tolerance.
9. When the piston is properly shimmed to the tolerances
listed in the table labeled Piston Clearance (Cold),
tighten the lock nut as shown in Appendix B.
10. Reinstall the piston cap with the same thickness
of shims as before and torque to the value listed in
Appendix B.
11. Reinstall the cylinder head.
12. Now remove an upper valve and measure dimension
X at the top of the piston shown in Appendix D—
Piston Assembly Details. If this measurement does not
fall within the tolerances in Appendix D, remove the
cylinder head and piston cap and adjust the shims as
necessary. Repeat the steps and measure dimension
X is within tolerance.
13. When the piston cap is properly shimmed, tighten the
socket head bolts in an alternating sequence and torque
the socket head bolts to the values listed in Appendix B.
14. Reinstall valves in the proper suction and discharge
openings. NOTE: For best results insert new valve
gaskets before reinstalling the valves.
15. Follow standard startup procedures.
5.5 Piston Rod Packing
Adjustment
On T-Style compressors the piston rod packing should
be adjusted or replaced when leakage is prevalent.
Adjust packing by tightening packing nuts as shown in
Figure 5.5.
NOTE: Fill crankcase with
oil through this opening.
Figure 5.5: Adjusting nuts for packing
(Applies to models T791 and FT891 only)
NOTE: Compressor models D791 and FD891 do not
have adjustable packing nuts.
Typically, it is a good idea to replace piston rod packing
and piston rings at the same time. For instructions on
replacing the piston rod packing, see section 5.6.
5.6 Cylinder and Packing
Replacement
Cylinders very seldom require replacement if the compressor
is properly maintained. The primary cause of damage to
cylinders is corrosion or the entry of solid debris or liquid
into the compression chamber. Improper storage methods
can also result in corrosion damage to the cylinder. For
proper storage instructions, refer to Appendix F.
If the cylinder is damaged or corroded, use a honing
device to smooth the cylinder bore and then polish it
to the value shown in Appendix B. If more than .005 of
an inch must be removed to smooth the bore, replace
the cylinder. Cylinder liners and oversized rings are not
available. OVERBORING THE CYLINDER RESULTS IN
GREATLY REDUCED RING LIFE.
Many compressor services require removal of the
cylinder. While the compressor is disassembled, special
care should be taken to avoid damage or corrosion to
the cylinder. If the compressor is to be left open for more
than a few hours, bare metal surfaces should be coated
with rust preventative.
When reassembling the compressor, make sure the
bolts are retightened using the torque values listed in
Appendix B.
17

Packing Replacement
NOTE: In this section, there are two sets of instructions:
one for D-Style compressors and another for T-Style
compressors. Before performing any maintenance,
identify the compressor style and model and refer to the
instructions for that model.
For specific construction details and actual part numbers,
consult Appendix D. Be careful to arrange packing sets
in the proper order.
CAUTION: Before installing the new packing on the
piston rod, bleed all pressure from the compressor
and piping and purge if necessary. After the new
piston rod packing is installed, the unit should be
pressure tested and checked for leaks at all joints
and gasket surfaces. When the compressor is used
with toxic, dangerous, flammable or explosive gases,
pressure and leak testing should be done with air or
a dry, inert gas such as nitrogen.
Cleanliness:
Sealing a reciprocating piston rod is a very difficult
task. Keep all parts, tools, and hands clean during
installation. New packing needs every chance it can get,
so keep it clean.
Workmanship:
Corken’s compressors are a precision piece of equipment
with very close tolerances so treat them with care and
never hammer parts in or out of the compressor.
Packing Configuration
The packing for the models 791 and 891 compressors
uses a combination of segmented packing and V-ring
packing. Refer to Appendix D for details on each packing
assembly. Use the model identification table in Appendix A
to identify the compressor style and packing configuration
and refer to the section that applies to that model.
5.6.1 D-Style Models D791 and FD891
On models D791 and FD891 there is one set of V-ring
packing inside a packing cartridge that attaches to
a packing barrel. The packing cartridge holds the
segmented packing inside the packing barrel (see
packing details in Appendix D).
Disassemble D-Style Packing
1. Depressurize and open the compressor.
2. Remove the cylinder cap, cylinder heads, pistons, and
cylinder.
3. Remove the packing barrels by prying upwardly
through the inspection plate opening under each one
and lifting entire packing barrel and cartridge assembly
up from piston rod.
4. Remove the four socket head screws that hold the
packing cartridge to the barrel.
5. Remove segmented packing and cartridge from barrel.
6. Remove lower retainer ring, washers, packing spring,
and old V-ring packing from packing cartridge.
Reassemble D-Style Packing
1. Replace packing as required. The segmented packing
and cups are located in the packing barrel while the
V-ring packing is located in the packing cartridge.
NOTE: Always use new O-rings when replacing the
packing barrel and cartridge.
2. V-ring packing set:
NOTE: The instructions below are for packing
specification J. Depending on the packing specification
used in on the compressor, the order of assembly
for the packing rings, V-ring packing, washers, and
packing spring will vary. Refer to Appendix D to
view the V-ring packing arrangements and follow the
order of assembly and V-ring direction. If the packing
arrangement in the compressor being currently
serviced is not known, refer to the model number
identification table listed in Appendix A.
a. Clean and lightly oil the packing area inside the
packing cartridge.
b. Insert the oil deflector ring through the bottom
opening of the packing cartridge.
c. Insert the first retainer ring followed by a washer.
d. Insert the packing spring followed by another
washer.
e. Insert a male packing ring followed by four V-rings
and one female packing ring. NOTE: Insert
packing rings and V-rings one at a time. Refer
to Appendix D for the proper direction of the
male and female packing rings and V-rings.
f. Lastly, insert the final washer. Push in on the
washer and install the second retainer ring.
3. Segmented packing:
NOTE: The instructions below are for packing
specification G. Depending on the packing
specification used in the compressor, the order of
assembly for the segmented packing arrangement
(radial or tangent) will vary. Refer to Appendix D
to view the segmented packing arrangements. If
you do not know the packing arrangement used
in the compressor, refer to the model number
identification table listed in Appendix A.
18

a. Clean the segmented packing cups and the area
inside the packing barrel.
b. Insert the segmented packing cups, segmented
packing pairs, and backup rings one at a time in
the order shown in Appendix D.
c. Reattach the packing cartridge to the packing
barrel using the four socket head screws.
4. Install three O-rings on the packing barrel and packing
cartridge as shown in the D-Style Crosshead Guide
Assembly Details in Appendix D.
5. Install the packing installation cone part number
3905 over the threaded end of the piston rod as
shown in Appendix D-Connecting Rod and Crosshead
Assembly Details.
6. Carefully install barrel/cartridge assemblies over the
piston rods, noting the alignment of the barrels as they
sit on the crosshead guide. Align the pin on one of the
barrels with the slot in the other barrel as shown in
Appendix D—Crosshead Guide Parts Details.
7. Remove packing installation cone.
8. Replace pistons, cylinders, heads, and cylinder
cap. See details in Section 4.4 for proper assembly
of pistons.
9. Rotate the flywheel by hand to ensure all components
are properly assembled.
5.6.2 T-Style Models T791 and T891
On Models T791, T891, and FT891 there are two sets
of V-ring packing in a single packing cartridge. The
cartridge is held in the crosshead guide by a cartridge
holddown screw. A separate packing adapter holds the
segmented packing inside the packing barrel.
Disassemble T-Style Packing
1. Depressurize and open the compressor.
2. Remove the cylinder cap, cylinder heads, pistons, and
cylinder.
3. Remove the packing barrels.
4. Remove the four socket head screws that hold packing
adapter to the barrel.
5. Remove segmented packing and cups from barrel.
6. Remove cartridge holddown screws with the special
wrench (part number 2409-X) supplied with the
compressor, and remove the cages and packing
cartridges as shown in T-Style Crosshead Guide
Assembly Details in Appendix D.
7. To remove the lower V-ring packing set, remove the
adjusting screw at the bottom of the packing cartridge
followed by the washers, packing spring, and old
packing.
8. To remove the middle V-ring packing set, remove
upper retainer ring followed by the washers, packing
spring, and old packing.
9. Repeat this process for the other side of the compressor.
Reassemble T-Style Packing
1. Replace packing as required. The segmented packing
and cups are located in the packing barrel while the
V-ring packing is located in the packing cartridge.
NOTE: Always use new O-rings when replacing the
packing barrel and cartridge.
2. Lower V-ring packing set:
NOTE: The instructions below are for packing
specification G. Depending on the packing
specification used in on the compressor, the
order of assembly for the packing rings, V-ring
packing, washers, and packing spring will vary.
Refer to Appendix D to view the V-ring packing
arrangements and follow the order of assembly
and V-ring direction. If the packing arrangement
in the compressor being currently serviced is not
known, refer to the model number identification
table listed in Appendix A.
a. Clean and lightly oil the packing area inside the
packing cartridge.
b. Insert the first retainer ring followed by a washer
through the bottom of the packing cartridge.
c. Insert the packing spring followed by another washer.
d. Insert a male packing ring followed by four
V-rings and one female packing ring. NOTE:
Insert packing rings and V-rings one at a time.
Refer to Appendix D for the proper direction of
the packing rings and V-rings.
e. Lastly, install and tightened the adjusting screw
until the PTFE locking device located on the side of
the adjusting screw is engaged with the first thread
of the packing cartridge. DO NOT OVER TIGHTEN!
The PTFE locking device should engage (slightly
bent) the first thread but not break off.
3. Middle V-ring packing set:
a. Clean and lightly oil the packing area inside the
packing cartridge.
b. Insert the second retainer ring followed by a
washer through the top of the packing cartridge.
19

c. Insert a female packing ring followed by four
V-rings and one male packing ring. NOTE: Insert
packing rings and V-rings one at a time. Refer
to Appendix D for the proper direction of the
male and female packing rings and V-rings.
d. Insert a washer and a packing spring followed by
another washer.
e. Lastly, push in on the washer and insert the third
retainer ring.
f. Install two O-rings on the packing cartridge as
shown in the T-Style Crosshead Guide Assembly
Details in Appendix D.
4. Segmented packing:
NOTE: The instructions below are for packing
specification G. Depending on the packing
specification used in the compressor, the order of
assembly for the segmented packing arrangement
(radial or tangent) will vary. Refer to Appendix D
to view the segmented packing arrangements. If
you do not know the packing arrangement used
in the compressor, refer to the model number
identification table listed in Appendix A.
a. Clean the segmented packing cups and the area
inside the packing barrel. Replace the O-ring on
the packing cup.
b. Insert the segmented packing cups, spacer,
segmented packing pairs, and backup rings one
at a time in the order shown in Appendix D.
c. Reattach the packing adapter to the packing
barrel using the four socket head screws.
d. Install TWO O-rings on the packing barrel as
shown in the T-Style Crosshead Guide Assembly
Details in Appendix D.
5. Install the packing installation cone (part number 3905)
over the threaded end of the piston rod as shown in
Connecting Rod and Crosshead Assembly Details -
Appendix D.
6. NOTE: Before installing the packing cartridge over
the packing cone and piston rod, ATTACH THE TWO
O-RINGS SHOW IN THE T-STYLE CROSSHEAD
GUIDE ASSEMBLY DETAILS-APPENDIX D. Next,
insert the oil deflector ring through the side opening
of the packing cartridge. The oil deflector ring should
rest on top of the lower packing set. Make sure the oil
deflector ring is centered over the piston rod opening
before sliding packing cartridge over the installation
cone and piston rod.
7. Install cages.
8. Install and tighten holddown screws with Corken’s
special compressor wrench.
9. Install packing barrels. NOTE: Align the pin on one of
the barrels with the slot in the other barrel as shown in
Appendix D—Crosshead Guide Parts Details.
10. Remove the packing installation cone.
11. Replace cylinder, pistons, cylinder heads, and cylinder
cap. See details in Sections 5.2 through 5.4 for proper
assembly of pistons.
12. Rotate the flywheel by hand to ensure proper assembly.
5.7 Bearing Replacement for
Crankcase and Connecting Rod
1. To replace the crankcase roller bearings, wrist pin bushing,
and connecting rod bearings, begin by removing the
cylinder caps, cylinder heads, cylinder, pistons, packings,
crosshead guide, and crosshead assemblies.
2. Drain the crankcase and remove the inspection cover.
3. Before disassembly, choose and mark one connecting
rod and the corresponding connecting rod cap. DO
NOT MIX CONNECTING RODS AND CAPS. Loosen
and remove the connecting rod bolts in order to
remove the crosshead and connecting rod assembly.
5.7.1 Wrist Pin Bushing Replacement
1. To replace the wrist pin bushing, remove the retainer
rings that position the wrist pin in the crosshead.
2. Press out the wrist pin so the crosshead and connecting
rod can be separated. Inspect the wrist pin for wear
and damage and replace if necessary.
3. Press out the old wrist pin bushing and press a new
bushing into the connecting rod. DO NOT MACHINE
THE O.D. OR I.D. OF THE BUSHING BEFORE
PRESSING INTO CONNECTING ROD.
4. Make sure the lubrication hole in the bushing matches
the oil passage in the connecting rod. If the holes do
not align, drill out the bushing through the connecting
rod lubricant passage with a long drill. Bore the wrist
pin bushing I.D. as indicated (see Appendix D for
details). Over boring the bushing can lead to premature
failure of the wrist pin bushing.
5. Inspect the oil passage for debris and clean thoroughly
before proceeding.
6. Press the wrist pin back into the crosshead and wrist
pin bushing and reinstall retainer rings. NOTE: The
fit between the wrist pin and bushing is tighter than
lubricated air compressors and combustion engines.
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