CAT Pumps 2530 User manual

25PFR PLUNGER PUMP SERVICE MANUAL
25 FRAME SPLIT MANIFOLD: 2530, 2531, 2537
SPECIFICATIONS: Maximum specifications refer to individual attributes. It is not
implied that all maximums can be performed simultaneously. If more than one
maximum is considered, check with your CAT PUMPS supplier to confirm the
proper performance and pump selection. Refer to individual pump Data Sheets for
complete specifications, parts list and exploded view.
LUBRICATION: Fill crankcase with CAT PUMPS custom-blend, ISO-68 hydraulic
oil per pump specifications [84 oz., 2.5 L]. DO NOT RUN PUMP WITHOUT OIL IN
CRANKCASE. Change initial fill after 50 hours running period. Thereafter, change
oil every 3 months or 500 hour intervals. Oiler adjustment is vertical to start feed,
horizontal to stop feed, dial to adjust flow rate. Additional lubrication may be re-
quired with increased hours of operation and temperature.
PUMP ROTATION: Pump was designed for forward rotation to allow optimum
lubrication of the crosshead area. Reverse rotation is acceptable if the crankcase oil
level is increased slightly above center dot to assure adequate lubrication.
PULLEY SELECTION: Select size of motor pulley required to deliver the desired
flow from Horsepower Requirement and Pulley Selection Chart (refer to Tech
Bulletin 003 or individual Data Sheet).
MOTOR SELECTION: The motor or engine driving the pump must be of adequate
horsepower to maintain full RPM when the pump is under load. Select the electric
motor from the Horsepower Requirement Chart according to required pump
discharge flow, maximum pressure at the pump and drive losses of approximately
3-5%. Consult the manufacturer of gas or diesel engine for selection of the proper
engine size.
MOUNTING: Mount the pump on a rigid, horizontal surface in a manner to permit
drainage of crankcase oil. An uneven mounting surface will cause extensive
damage to the pump base. To minimize piping stress, use appropriate flexible
hose to inlet and discharge ports. Use the correct belt; make sure pulleys are
aligned. Excessive belt tension may be harmful to the bearings. Hand rotate pump
before starting to be certain shaft and bearings are free moving.
LOCATION: If the pump is used in extremely dirty or humid conditions, it is
recommended pump be enclosed. Do not store or operate in excessively high
temperature areas or without proper ventilation.
INLET CONDITIONS: Refer to complete Inlet Condition Check-List in this manual
before starting system. DO NOT STARVE THE PUMP OR RUN DRY.
Temperatures above 130°F are permissible. Add 1/2 PSI inlet pressure per each
degree F over 130°F. Elastomer or RPM changes may be required. See Tech
Bulletin 002 or call CAT PUMPS for recommendations.
C.A.T.: Installation of a C.A.T. (Captive Acceleration Tube) is recommended in
applications with stressful inlet conditions such as high temperatures, booster pump
feed, long inlet lines or quick closing valves.
DISCHARGE CONDITIONS: OPEN ALL VALVES BEFORE STARTING SYSTEM to
avoid deadhead overpressure condition and severe damage to the pump or system.
Install a Pulsation Dampening device on the discharge head or in the discharge line
as close to the head as possible. Be certain the pulsation dampener (Prrrrr-o-lator) is
properly precharged for the system pressure (see individual Data Sheet.)
Areliable Pressure Gauge should be installed near the discharge outlet of the high
pressure manifold. This is extremely important for adjusting pressure regulating
devices and also for proper sizing of the nozzle or restricting orifice. The pump is
rated for a maximum pressure; this is the pressure which would be read at the
discharge manifold of the pump, NOT AT THE GUN OR NOZZLE.
Use PTFE thread tape or pipe thread sealant (sparingly) to connect accessories or
plumbing. Exercise caution not to wrap tape beyond the last thread to avoid
tape from becoming lodged in the pump or accessories. This condition will cause a
malfunction of the pump or system.
PRESSURE REGULATION: All systems require both a primary pressure regulating
device (i.e., regulator, unloader) and a secondary pressure safety relief device
(i.e., pop-off valve, safety valve). The primary pressure device must be installed on
the discharge side of the pump. The function of the primary pressure regulating
device is to protect the pump from over pressurization, which can be caused by a
plugged or closed off discharge line. Over pressurization can severely damage the
pump, other system components and can cause bodily harm. The secondary safety
relief device must be installed in-line between the primary device and pump or on
the opposite side of the manifold. This will ensure pressure relief of the system if the
primary regulating device fails. Failure to install such a safely device will void the
warranty on the pump.
If a large portion of the pumped liquid is by-passed (not used) when the high
pressure system is running, this by-pass liquid should be routed to an adequately
sized, baffled supply tank or to drain. If routed to the pump inlet, the by-pass liquid
can quickly develop excessive heat and result in damage to the pump. A
temperature control device to shut the system down within the pump limits or multiple
THERMO VALVES must be installed in the by-pass line to protect the pump.
NOZZLES: A worn nozzle will result in loss of pressure. Do not adjust pressure
regulating device to compensate. Replace nozzle and reset regulating device to
system pressure.
PUMPED LIQUIDS: Some liquids may require a flush between operations or before
storing. For pumping liquids other than water, contact your CAT PUMPS supplier.
STORING: For extended storing or between use in cold climates, drain all pumped
liquids from pump and flush with antifreeze solution to prevent freezing and
damage to the pump. DO NOT RUN PUMP WITH FROZEN LIQUID (refer to Tech
Bulletin 083).
INSTALLATION AND START-UP INFORMATION
Optimum performance of the pump is dependent upon the entire liquid system and will be obtained only
with the proper selection, installation of plumbing, and operation of the pump and accessories.
WARNING
All systems require both a primary pressure regulating device (i.e., regulator, unloader) and a secondary pressure safety relief device (i.e., pop-off valve, safety valve).
Failure to install such relief devices could result in personal injury or damage to the pump or to system components. CAT PUMPS does not assume any liability or responsibility
for the operation of a customer’s high pressure system.
PN 30053 Rev H 1643
CAT PUMPS (U.K.) LTD.
1 Fleet Business Park, Sandy Lane, Church Crookham, Fleet
Hampshire GU52 8BF, England
Phone Fleet 44 1252-622031 — Fax [phone]
e-mail: [email protected]
N.V. CAT PUMPS INTERNATIONAL S.A.
Heiveldekens 6A, 2550 Kontich, Belgium
Phone [phone] — Fax [phone]
e-mail: [email protected] www.catpumps.be
CAT PUMPS DEUTSCHLAND GmbH
Buchwiese 2, D-65510 Idstein, Germany
Phone [phone] — Fax [phone]
e-mail: [email protected] www.catpumps.de
World Headquarters
CAT PUMPS
1681 - 94th Lane N.E. Minneapolis, MN 55449- 4324
Phone [phone] — FAX [phone]
e-mail: [email protected]
www.catpumps.com
International Inquiries
FAX [phone]
e-mail: [email protected]
®
The Pumps with Nine Lives

SERVICING THE VALVES
Disassembly
1. To service the Valves, the Discharge Manifold must be re-
moved. Using a M10 allen wrench remove the eight
Socket Head Screws.
2. Support the underside of the Discharge Manifold and
lightly tap the top back of the manifold with a soft mallet.
Two screwdrivers may be needed to further separate the
Discharge Manifold from the Inlet Manifold.
3. Remove the Discharge Manifold and place it crankcase
side up.
NOTE: The Discharge Valve Assembly is secured in
the upper chambers by the Discharge Valve Spacer,
while the Inlet Valve Assembly is secured in the lower
chambers by the Inlet Valve Adapter.
4. The Discharge Valve Spacers will remain in either the
Inlet Manifold or the Discharge Manifold. To remove the
Spacer from the manifold, insert two screwdrivers on
opposite sides under the machined lip on the outside of
the Spacer and pry out.
5. Use a reverse pliers to remove the Inlet Valve Adapters
from the Discharge Manifold or insert two screwdrivers
into the secondary groove on opposite sides of the
adapter and pry from valve chamber.
6. Both the Inlet and Discharge use the same Valve
Assembly. With a flat head screwdriver, carefully pry
the Seat, O-Ring, Valve, Spring and Retainer from the
manifold chamber.
CAUTION: Exercise caution to avoid scoring the
manifold chamber wall.
NOTE: This Valve Assembly does not snap together.
Reassembly
NOTE: For certain applications apply liquid gasket to
the O-Ring crevices and seal surfaces. See Tech
Bulletin 053 for model identification.
NOTE: EPDM elastomers require a silicone-base
lubricant.
1. Inspect the Spring Retainer for any scale buildup or wear
and replace as needed. Place the Spring Retainer into the
valve chamber.
Removal of Discharge Socket Head Screws Separation of Discharge Manifold from Inlet Manifold Discharge Manifold with both Inlet Valve Adapters and
Discharge Valve Spacers.
Removal of Discharge Valve Spacers Removal of Inlet Valve Adapters Discharge Valve Assembly
CAUTION: Before commencing with service, shut off drive (electric motor, gas or diesel engine) and turn off water supply to
pump. Relieve all discharge line pressure by triggering gun or opening valve in discharge line.
After servicing is completed, turn on water supply to pump, start drive, reset pressure regulating device and secondary valve, read
system pressure on the gauge at the pump head. Check for any leaks, vibration or pressure fluctuations and resume operation.

2. Examine the Spring for fatigue or breaks and replace as
needed. Place the Spring into the Retainer.
3. Examine the Valve for pitting or grooves and replace as
needed. Set the Valve onto the Spring with the concave
side down.
4. Place the Seat into the valve chamber with the concave
side down. Then apply liquid gasket to the O-Ring and
press squarely into the lip on the Spring Retainer.
NOTE: Effective with 6-95 mfg date, the O-Ring was
moved to the back side of the Seat with the O-Ring
installed first, onto the lip in the manifold chamber,
then the Seat with the machined O-Ring groove down.
NOTE: Effective with 11-95 mfg date, the Seat was
modified to a new thicker style, still with the O-Ring
installed first, onto the lip in the manifold chamber,
then the Seat with the machined O-Ring groove down.
5. Examine the Seat for any grooves, pitting or wear and
replace. Place the new Seat onto the the O-Ring with the
concave side down.
6. Look for wear or damage to both the inner and outer
O-Rings on the Inlet Adapter and replace.
7. Fit the O-Rings into both the outer groove and face
groove of the Inlet Adapter and apply liquid gasket into the
O-Ring crevice.
8. Press the Inlet Adapter into the lower manifold chamber.
9. Remove and examine both O-Rings on the Discharge
Valve Spacer for wear or cuts and replace as needed.
10. Fit the new O-Rings into the groove on the outside of the
Discharge Valve Spacer. Apply liquid gasket into the
O-Ring crevice and carefully press the Spacer completely
into the Discharge Manifold chamber with the smaller
diameter side down.
11. Replace Discharge Manifold over the Plunger Rods with
Discharge Valve Spacers to the top and Inlet Adapters to
the bottom. Tap with a soft mallet until completely seated
in chambers.
12. Reinstall the eight Socket Head Screws and torque in
sequence to specifications in torque chart.
NOTE: It is highly recommended that antiseize lubricant
(PN6119) be applied to the threads on all stainless
steel components to prevent galling.
IMPORTANT: Follow the torque sequence to assure
the proper alignment.
Inlet Valve Assembly Removal of I.M. Socket Head Screws Rotate Crankshaft to position plungers
Removal of Inlet Manifold Removal of Hi-Pressure Seals Removal of Lo-Pressure Seals

SERVICING THE SEALS
Disassembly
1. Remove the Discharge Manifold as described in SERVICING
THE VALVES section.
2. To service the seals the Inlet Manifold must be removed,
use a M10 allen wrench to remove the 4 Socket Head
Screws.
3. Support the Inlet Manifold and lightly tap the top back side
with a soft mallet. Remove the Inlet Manifold and place it
crankcase side down.
4. Use a reverse pliers to remove the Hi-Pressure Seals.
5. The Lo-Pressure Seals may stay on the Plungers or in the
Inlet Manifold.
6. Invert the Inlet Manifold with the crankcase side up.
7. Remove the Lo-Pressure Seal using a reverse pliers or
slide it off the Plunger by hand.
Reassembly
NOTE: If your pump has been built with special seals
and O-Rings, service with same type of special parts.
Refer to pump Data Sheet for correct parts or kits.
NOTE: For certain applications apply liquid gasket to
the O-Ring crevices and seal surfaces. See Tech
Bulletin 053 for model identification.
NOTE: EPDM elastomers require a silicone-base
lubricant.
1. Examine the Lo-Pressure Seal for wear or spring fatigue
and replace. Apply liquid gasket to the outside of the new
Lo-Pressure Seal and carefully press it into the Inlet
Manifold chamber with the spring down.
NOTE: When using alternate materials, the fit of the
special materials may be snug and require gently
driving the LPS into position with a cylinder of the
same diameter to assure a square seating and no
damage to the LPS.
2. Invert the Inlet Manifold and place the crankcase side
down. Examine the Hi-Pressure Seal for deformity or
wear and replace. Apply liquid gasket to the outside of the
new Hi-Pressure Seal and carefully press it into the Inlet
Manifold chamber with the metal side down.
SERVICING THE PLUNGERS
Disassembly
NOTE: The Ceramic Plungers and the Plunger
Retainers should be examined on the same schedule
as servicing the seals.
1. To service the Ceramic Plungers, first remove the Seal
Retainers.
2. Loosen the Plunger Retainer about three or four turns
using a M14 hex tool.
3. Grasp the Ceramic Plunger and push toward the
Crankcase until it separates from the Plunger Retainer.
4. Unthread the Plunger Retainer with Gasket, O-Ring,
Back-up-Ring and Ceramic Plunger. Remove the Keyhole
Washer and Barrier Slinger from the Plunger Rod.
Reassembly
1. Examine the Barrier Slinger for any wear or damage and
place on the Plunger Rod with the concave side facing
out.
2. Examine the Keyhole Washer and place on the Plunger
Rod with the slot down.
3. Examine the O-Ring and Back-up-Ring on the Plunger
Retainer and replace if worn or damaged. First install
the Gasket, then the O-Ring and Back-up-Ring. Lubricate
the Plunger Retainer O-Ring to avoid cutting during
installation.
4. If the Plunger Retainer unthreads from the stud during re-
moval, thread the stud into the retainer.
5. Examine the Ceramic Plunger for scoring, cracks or scale
and replace if needed. The Ceramic Plunger can be
cleaned with a scotchbrite pad. Slide the Ceramic Plunger
onto the retainer and stud assembly with the shallower
counterbore away from the retainer.
NOTE: Plunger can only be installed one direction. Do
not force into Plunger Rod.
NOTE: Do not lubricate wicks at initial start-up.
Operate for 10 to 15 minutes to allow grease from
LPS to penetrate the plunger surface, then lubricate
as needed.
6. Apply Loctite®242®to the threads of the Plunger Retainer
Stud and thread onto the Plunger Rod. Then torque to
specifications in chart.
Plunger Arrangement

7. Install new wicks in front half of seal retainer. Press rear
half of seal retainer into front half until ends are flush.
Holes should be to the top and bottom to line up with front
retainer holes. Slide Seal Retainers over plungers and
press into crankcase chamber until flush with oil seal.
8. Rotate the Crankshaft to line up the outside Plungers.
Then lightly lubricate the Plungers with oil.
9. Carefully slide the Inlet Manifold over the Ceramic
Plungers and press until flush with the Crankcase.
10. Reinstall the four Inlet Socket Head Screws and torque to
specifications in chart.
11. The Hi-Pressure Seals may shift while installing the Inlet
Manifold. Use one of the Discharge Valve Spacers to
press the Seals back into position.
12. Carefully press the Discharge Manifold into the Inlet
Manifold. Use a soft mallet to tap into place and reinstall
the eight Socket Head Screws. Torque in sequence to
specifications in torque chart.
TORQUE SEQUENCE
SERVICING THE CRANKCASE SECTION
1. While Inlet Manifold, Plungers and Seal Retainers are
removed, examine Crankcase Oil Seals for leaking and
wear.
2. Check for any signs of leaking at Rear Cover or Dipstick.
3. Check oil level and for evidence of water in oil. Change oil
on a regular schedule. See Preventative Maintenance
Check-List.
4. Rotate Crankshaft by hand to feel for smooth bearing
movement.
5. Examine Crankshaft Oil Seals externally for drying,
cracking or leaking.
6. Consult CAT PUMPS or your local distributor if Crankcase
service is required. See also Tech Bulletin 035.
See Section II of the Plunger Pump Service DVD for
additional information.
51 37
84 26
Loctite®and 242®are registered trademarks of Henkel Corporation

PREVENTATIVE MAINTENANCE CHECK-LIST
Check Daily Weekly 50 hrs. 500 hrs.* 1500 hrs.** 3000 hrs.**
Clean Filters x
Oil Level/Quality x
Oil Leaks x
Water Leaks x
Belts, Pulley x
Plumbing x
Initial Oil Change x
Oil Change x
Seal Change x
Valve Change x
Accessories x
TECHNICAL BULLETIN REFERENCE CHART
No. Subject Models
002 Inlet Pressure VS Liquid Temperature All Models
003 Power Unit Drive Packages 3PFR - 68PFR, 10FR - 60FR
024 Lubrication of Lo-Pressure Seals All Models
035 Servicing Crankcase Section 7PFR - 60PFR
036 Cylinder and Plunger Reference Chart All Models
043 LPS and HPS Servicing All Plunger Models
053 Liquid Gasket All Plunger NAB-S.S. Models
064 By-Pass Hose Sizing All Unloaders/Regulators
074 Torque Chart Piston and Plunger Pumps
076 Valve Seat and O-Ring 2530 and 2537
077 Oil Drain Kit All Models (except 2SF/4SF)
081 Seal Case and Wick 2530 and 2537
083 Winterizing a Pump All Models
085 M8 Keyway 25FR, 25PFR, 28PFR
095 Galling Preventative Stainless Steel Pumps
* If other than CAT PUMPS custom-blend, multi-viscosity, ISO-68
hydraulic oil is used, change cycle should be every 300 hours.
** Each system’s maintenance cycle will be exclusive. If system per-
formance decreases, check immediately. If no wear at 1500 hours,
check again at 2000 hours and each 500 hours until wear is ob-
served. Valves typically require changing every other seal change.
Duty cycle, temperature, quality of pumped liquid and inlet feed
conditions all effect the life of pump wear parts and service cycle.
** Remember to service the regulator/unloader at each seal servicing
and check all system accessories and connections before resuming
operation.
Refer to service DVD for additional assistance.
INLET CONDITION CHECK-LIST
Review Before Start-Up
Inadequate inlet conditions can cause serious malfunctions in the best designed
pump. Surprisingly, the simplest of things can cause the most severe problems or go
unnoticed to the unfamiliar or untrained eye. REVIEW THIS CHECK-LIST BEFORE
OPERATION OF ANY SYSTEM. Remember, no two systems are alike, so there can
be no ONE best way to set-up a system. All factors must be carefully considered.
INLET SUPPLY should exceed the maximum flow being delivered by the pump to
assure proper performance.
❏Open inlet shut-off valve and turn on water supply to avoid starving pump. DO
NOT RUN PUMP DRY.
❏Temperatures above 130°F are permissible. Add 1/2 PSI inlet pressure per each
degree F over 130°F. Elastomer or RPM changes may be required. See Tech
Bulletin 002 or call CAT PUMPS for recommendations.
❏Avoid closed loop systems especially with high temperature, ultra-high pressure
or large volumes. Conditions vary with regulating/unloader valve.
❏Low vapor pressure liquids, such as solvents, require a booster pump and C.A.T.
to maintain adequate inlet supply (where compatible).
❏Higher viscosity liquids require a positive head and a C.A.T. to assure adequate
inlet supply.
❏Higher temperature liquids tend to vaporize and require positive heads and
C.A.T. to assure adequate inlet supply.
❏When using an inlet supply reservoir, size it to provide adequate liquid to
accommodate the maximum output of the pump, generally a minimum of 6-10
times the GPM (however, a combination of system factors can change this
requirement); provide adequate baffling in the tank to eliminate air bubbles and
turbulence; install diffusers on all return lines to the tank.
INLET LINE SIZE should be adequate to avoid starving the pump.
❏Line size must be a minimum of one size larger than the pump inlet fitting. Avoid
tees, 90 degree elbows or valves in the inlet line of the pump to reduce the risk of
flow restriction and cavitation.
❏The line MUST be a FLEXIBLE hose, NOT a rigid pipe, and reinforced on SUCTION
systems to avoid collapsing.
❏The simpler the inlet plumbing the less the potential for problems. Keep the
length to a minimum, the number of elbows and joints to a minimum (ideally no
elbows) and the inlet accessories to a minimum.
❏Use pipe sealant to assure air-tight, positive sealing pipe joints.
INLET PRESSURE should fall within the specifications of the pump.
❏Acceleration loss of liquids may be increased by high RPM, high temperatures,
low vapor pressures or high viscosity and may require pressurized inlet
and C.A.T. to maintain adequate inlet supply. DO NOT USE C.A.T. WITH
SUCTION INLET.
❏Optimum pump performance is obtained with +20 PSI (1.4 BAR) inlet pressure
and a C.A.T. for certain applications. With adequate inlet plumbing, most pumps
will perform with flooded suction. Maximum inlet pressure is 70 PSI (4.9 BAR).
❏After prolonged storage, pump should be rotated by hand and purged of air to
facilitate priming. Disconnect the discharge port and allow liquid to pass through
pump and measure flow.
INLET ACCESSORIES are offered to protect against over pressurization,
contamination or temperature and control flow.
❏A shut-off valve is recommended to facilitate maintenance.
❏Installation of a C.A.T. is essential in applications with stressful conditions such
as high temperatures, booster pump feed or long inlet lines. Do not use C.A.T.
with negative inlet pressure.
❏A stand pipe can be used in some applications to help maintain a positive head
at the pump inlet line.
❏Inspect and clean inlet filters on a regular schedule to avoid flow restriction.
❏A pressure transducer is necessary to accurately read inlet pressure. Short
term, intermittent cavitation will not register on a standard gauge.
❏All accessories should be sized to avoid restricting the inlet flow.
❏All accessories should be compatible with the solution being pumped to prevent
premature failure or malfunction.
❏Optional inlet protection can be achieved by installing a pressure cut off switch
between the inlet filter and the pump to shut off pump when there is no positive
inlet pressure.
BY-PASS TO INLET Care should be exercised when deciding the method of by-pass
from control valves.
❏It is recommended the by-pass be directed to a baffled reservoir tank, with at
least one baffle between the by-pass line and the inlet line to the pump.
❏Although not recommended, by-pass liquid may be returned to the inlet line
of the pump if the system is properly designed to protect your pump. When a
pulsation dampener is used, a PRESSURE REDUCING VALVE must be
installed on the inlet line (BETWEEN THE BY-PASS CONNECTION AND THE
INLET TO THE PUMP) to avoid excessive pressure to the inlet of the pump. It is
also recommended that a THERMO VALVE be used in the by-pass line to moni-
tor the temperature build-up in the by-pass loop to avoid premature seal failure.
❏A reinforced, flexible, low pressure hose rated up to 300 PSI should be used for
routing by-pass back to the pump inlet.
❏Caution should be exercised not to undersize the by-pass hose diameter and
length. Refer to Technical Bulletin 064 for additional information on the size and
length of the by-pass line.
❏Check the pressure in the by-pass line to avoid over pressurizing the inlet.
❏The by-pass line should be connected to the pump inlet line at a gentle angle of
45° or less and no closer than 10 times the pump inlet port diameter e.g. 1-1/2"
port size = 15" distance from pump inlet port.
TORQUE CHART
Tool Size Torque
Pump Item Thread [Part No.] in.lbs. ft.lbs. Nm
Plunger Retainer M7 M14 Hex 108 9.0 12.2
[25053]
Inlet Manifold Screws M12 M10 Allen 355 30.0 40
[33047]
Discharge Manifold Screws M12 M10 Allen 355 30.0 40
[33047]
Rear Cover/ M8 M13 Hex 115 9.58 13
Bearing Cover Screws [25324]
Connecting Rod Screws M8 M13 Hex 216 18.0 24
[25324]
Bubble Oil Gauge M28 Oil Gauge Tool 45 3.8 5
[44050]

Q. How can I find the RPM needed to get specific GPM
(Gallons Per Minute) I want? Rated RPM
A. Desired RPM = Desired GPM x Rated GPM
Q. I have to run my pump at a certain RPM. How do I figure
the GPM I’ll get? Rated GPM
A. Desired GPM = Desired RPM x Rated RPM
Q. Is there a simple way to find the approximate horsepower
I’ll need to run the pump?
A. Electric Brake GPM x PSI (Standard 85%
Horsepower Required =1460 Mech. Efficiency)
Q. What size motor pulley should I use?
Pump RPM
A. Pump Pulley (Outer Diameter) x Motor/Engine RPM
Q. How do I calculate the torque for my hydraulic drive
system? GPM x PSI
A. Torque (ft. lbs.) = 3.6 RPM
( )
One or several of the conditions shown in the chart below may
contribute to cavitation in a system resulting in premature wear,
system downtime and unnecessary operating costs.
CONDITION SOLUTION
Inadequate inlet ●Increase line size to the inlet port or one size
line size larger
Water hammering ●Install C.A.T. Tube
liquid acceleration/ ●Move pump closer to liquid supply
deacceleration
Rigid Inlet Plumbing ●Use flexible wire reinforced hose to absorb
pulsation and pressure spikes
Excessive Elbows in ●Keep elbows to a minimum and less than 90°
Inlet Plumbing
Excessive Liquid ●Use Thermo Valve in bypass line
Temperature ●Do not exceed pump temperature specifications
●Substitute closed loop with baffled holding tank
●Adequately size tank for frequent or high
volume bypass
●Pressure feed high temperature liquids
●Properly ventilate cabinets and rooms
Air Leaks in Plumbing ●Check all connections
●Use PTFE thread tape or pipe thread sealant
Agitation in Supply ●Size tank according to pump output —
Tank Minimum 6-10 times system GPM
●Baffle tank to purge air from liquid and
separate inlet from discharge
High Viscosity Liquids ●Verify viscosity against pump specifications
before operation
●Elevate liquid temperature enough to reduce
viscosity
●Lower RPM of pump
●Pressure feed pump
●Increase inlet line size
Clogged Filters ●Perform regular maintenance or use clean
filters to monitor build up
●Use adequate mesh size for liquid and pump
specifications
Handy Formulas to Help You
(Consult
Engine Mfr.)
TYPICAL RESERVOIR TANK
RECOMMENDED 6 TO 10 TIMES SYSTEM CAPACITY
Avoid Cavitation Damage
1/4 5/16 3/8 1/2 5/8 3/4 1"
0.5 16 5 2
154 20 7 2
2180 60 25 6 2
3380 120 50 13 4 2
4220 90 24 7 3
5320 130 34 10 4
6220 52 16 7 1
8300 80 25 10 2
10 450 120 38 14 3
15 900 250 80 30 7
20 1600 400 121 50 12
25 650 200 76 19
30 250 96 24
40 410 162 42
50 600 235 62
60 370 93
*At a fixed flow rate with a given size hose, the pressure drop across a given hose length
will be directly proportional. A 50 ft. hose will exhibit one-half the pressure drop of a 100
ft. hose. Above values shown are valid at all pressure levels.
PRESSURE DROP IN PSI PER 100 FT OF HOSE
WITH TYPICAL WATER FLOW RATES
Hose Inside Diameters, Inches
Water*
Flow
Gal/Min
HOSE FRICTION LOSS
Water
GPM
1
2
3
5
8
10
15
25
40
60
80
100
Steel Pipe—Nominal Dia.
1/4 3/8 1/2 3/4 1 11/411/2
8.5 1.9
30 7.0 2.1
60 14 4.5 1.1
150 36 12 2.8
330 86 28 6.7 1.9
520 130 43 10 3.0
270 90 21 6.2 1.6
670 240 56 16 4.2 2.0
66 17 8.0
37 17
52 29
210 107 48
Brass Pipe—Nominal Dia.
1/4 3/8 1/2 3/4 1 11/411/2
6.0 1.6
20 5.6 1.8
40 11 3.6
100 28 9.0 2.2
220 62 21 5.2 1.6
320 90 30 7.8 2.4
190 62 16 5.0 1.5
470 150 40 12 3.8 1.7
39 11 5.0
23 11
40 19
61 28
Copper Tubing O.D. Type L
1/4 3/8 1/2 5/8 3/4 7/8
120 13 2.9 1.0
400 45 10 3.4 1.3
94 20 6.7 2.6
230 50 17 6.1 3.0
500 120 40 15 6.5
180 56 22 10
120 44 20
330 110 50
550 200 88
WATER LINE PRESSURE LOSS
PRESSURE DROP IN PSI PER 100 FEET
1/2 0.622 0.41 18.5 9.3 0.78 1.67 3.71 0.93 3.33
3/4 0.824 0.54 24.5 12.3 1.03 2.21 4.90 1.23 4.41
1 1.049 0.69 31.2 15.6 1.31 2.81 6.25 1.56 5.62
11/41.380 0.90 41.0 20.5 1.73 3.70 8.22 2.06 7.40
11/21.610 1.05 48.0 24.0 2.15 4.31 9.59 2.40 8.63
2 2.067 1.35 61.5 30.8 2.59 5.55 12.30 3.08 11.60
21/22.469 1.62 73.5 36.8 3.09 6.61 14.70 3.68 13.20
3 3.068 2.01 91.5 45.8 3.84 8.23 18.20 4.57 16.40
4 4.026 2.64 120.0 60.0 5.03 10.80 23.90 6.00 21.60
Nominal
Pipe
Size
Inches
Inside
Diameter
Inches
RESISTANCE OF VALVES AND FITTINGS
Gate
Valve Globe Valve Angle Valve 45˚ Elbow 90˚ Elbow
180˚
Close
Ret
Tee
Thru
Run
Arriving at a total line pressure loss, consideration should then be given to
pressure loss created by valves, fittings and elevation of lines.
If a sufficient number of valves and fittings are incorporated in the system to
materially affect the total line loss, add to the total line length, the equivalent
length of line of each valve or fitting.
Tee
Thru
Branch
Equivalent Length of Standard Pipe in Feet
Bypass Line
(from regulator or unloader)
Level Sensing
Device
Bypass Line
(from regulator or
unloader)
MIN. 4"
1.5 x D (Min.)
Minimum Two Baffles
Sealed at Bottom
Minimum
Liquid
Level
FILTER
MIN. 4"
Flexible Hose
to Pump
Supply Line
(Dia of pipe)
T
XD
→
→
→
→
→
→
→
→
→

DIAGNOSIS AND MAINTENANCE
One of the most important steps in a high pressure system is to establish a regular maintenance program. This will vary slightly with each
system and is determined by various elements such as the duty cycle, the liquid being pumped, the actual specifications vs rated specifications
of the pump, the ambient conditions, the inlet conditions and the accessories in the system. A careful review of the necessary inlet conditions
and protection devices required before the system is installed will eliminate many potential problems.
CAT PUMPS are very easy pumps to service and require far less frequent service than most pumps. Typically, only common tools are required,
making in-field service convenient, however, there are a few custom tools, special to certain models, that do simplify the process. This service
manual is designed to assist you with the disassembly and reassembly of your pump. The following guide will assist in determining the cause
and remedy to various operating conditions. You can also review our FAQ or SERVICE sections on our WEB SITE for more facts or contact
CAT PUMPS directly.
PROBLEM PROBABLE CAUSE SOLUTION
Low pressure •Worn nozzle. •Replace with properly sized nozzle.
•Belt slippage. •Tighten belt(s) or install new belt(s).
•Air leak in inlet plumbing. •Tighten fittings and hoses. Use PTFE liquid or tape.
•Pressure gauge inoperative or not registering accurately. •Check with new gauge. Replace worn or damaged gauge.
•Relief valve stuck, partially plugged or improperly adjusted. •Clean/adjust relief valve. Replace worn seats/valves and o-rings.
•Inlet suction strainer (filter) clogged or improperly sized. •Clean filter. Use adequate size filter. Check more frequently.
•Abrasives in pumped liquid. •Install proper filter.
•Leaky discharge hose. •Replace discharge hose with proper rating for system.
•Inadequate liquid supply. •Pressurize inlet and install C.A.T.
•Severe cavitation. •Check inlet conditions.
•Worn seals. •Install new seal kit. Increase frequency of service.
•Worn or dirty inlet/discharge valves. •Clean inlet/discharge valves or install new valve kit.
Pulsation •Faulty Pulsation Dampener. •Check precharge. If low, recharge, or install a new dampener.
•Foreign material trapped in inlet/discharge valves. •Clean inlet/discharge valves or install new valve kit.
Water leak
•Under the manifold •Worn High Pressure or Lo-Pressure Seals. •Install new seal kit. Increase frequency of service.
•Worn adapter o-rings. •Install new o-rings.
•Into the crankcase •Humid air condensing into water inside the crankcase. •Install oil cap protector. Change oil every 3 months or 500 hours.
•Excessive wear to seals and V-Packings. •Install new seal kit. Increase frequency of service.
Knocking noise
•Inlet supply •Inadequate inlet liquid supply. •Check liquid supply. Increase line size, pressurize or install C.A.T.
•Bearing •Broken or worn bearing. •Replace bearing.
•Pulley •Loose pulley on crankshaft •Check key and tighten set screw.
Oil leak
•Crankcase oil seals. •Worn crankcase oil seals. •Replace crankcase oil seals.
•Crankshaft oil seals and o-rings. •Worn crankshaft oil seals or o-rings on bearing cover. •Remove bearing cover and replace o-rings and/or oil seals.
•Drain plug •Loose drain plug or worn drain plug o-ring. •Tighten drain plug or replace o-ring.
•Bubble gauge •Loose bubble gauge or worn bubble gauge gasket. •Tighten bubble gauge or replace gasket.
•Rear cover •Loose rear cover or worn rear cover o-ring. •Tighten rear cover or replace o-ring.
•Filler cap •Loose filler cap or excessive oil in crankcase. •Tighten filler cap. Fill crankcase to specified capacity.
Pump runs extremely rough
•Inlet conditions •Restricted inlet or air entering the inlet plumbing •Correct inlet size plumbing. Check for air tight seal.
•Pump valves •Stuck inlet/discharge valves. •Clean out foreign material or install new valve kit.
•Pump seals •Leaking High Pressure or Lo-Pressure seals. •Install new seal kit. Increase frequency of service.
Premature seal failure •Scored plungers. •Replace plungers.
•Over pressure to inlet manifold. •Reduce inlet pressure per specifications.
•Abrasive material in the liquid being pumped. •Install proper filtration at pump inlet and clean regularly.
•Excessive pressure and/or temperature of pumped liquid. •Check pressure and inlet liquid temperature.
•Running pump dry. •DO NOT RUN PUMP WITHOUT LIQUID.
•Starving pump of adequate liquid. •Increase hose one size larger than inlet port size. Pressurize and
install C.A.T.
•Eroded manifold. •Replace manifold. Check liquid compatibility.