Pentair MYERS APLEX Series Manual

NOTE! To the installer: Please make sure you provide this manual to the owner of the equipment or to the responsible
party who maintains the system.
MODELS
MA-155L, MA-155M, MA-155M-HD,
SC-230,
RO-261
TRIPLEX PUMPS
INSTALLATION AND SERVICE MANUAL
Part # AP-03-105 | © 2014 Pentair Ltd. | 01/14/14

2 3
Engineering Data
MA-155L........................................................... 3
MA-155M.......................................................... 4
MA-155M-HD .................................................... 5
SC-230 ............................................................. 6
RO-261............................................................. 7
Dimensional Data ...............................................8–9
Installation, Operation, Lubrication, Maintenance
and Storage Instructions....................................... 10
Safety ............................................................. 10
Storage............................................................ 10
Pump Location and Piping Design...................... 10
Suction Piping ............................................10–11
Acceleration Head ............................................ 11
Discharge Piping .........................................11–12
Bypass Piping .................................................. 12
Lubrication ...................................................... 12
V-Belt Drive ............................................... 12, 14
Suggested Piping System for Plunger Pumps ...... 13
Direction of Rotation......................................... 14
Automatic (Safety) Shutdowns........................... 14
Crankshaft Assembly............................................ 14
General ........................................................... 14
Tapered Roller Bearings ...............................14–15
Cup Installation................................................ 15
Installing Crankshaft ............................................ 15
Shim Adjustment of Tapered Roller Bearings....... 15
Installation of Crankshaft Oil Seal ...................... 15
Disassembly................................................15–16
Connecting Rod, Crosshead, Extension Rod, Crosshead
Pin and Wiper Box Assembly/Disassembly .............. 16
General ........................................................... 16
Installing Wrist Pin Bushings............................. 16
Bolting the Wrist Pin......................................... 17
Order of Assembly ............................................ 17
Oil Scoop ........................................................ 18
Wiper Box Assembly............................................. 18
General ........................................................... 18
“Poly Pak” Seal ............................................... 18
Mechanical Oil Seal.......................................... 18
Inserting the Extension Rod............................... 18
Stuffing Box, Packing and Plunger Assemblies ....... 19
General ........................................................... 19
Spring Loaded Packing ..................................... 19
J-Style Stuffing Box & Plunger Assembly
(Styles 838 and 858) ..................................19–20
Inserting the Plunger ........................................ 20
Installing the Gland .......................................... 20
Installing the Stuffing Box................................. 20
Connecting the Plunger..................................... 20
Packing ........................................................... 21
Plungers.......................................................... 21
Disc Valve Systems and Abrasion Resistant
Valve Construction ............................................... 21
General ........................................................... 21
Disc Valve and Abrasion Resistant
Valve Construction .......................................21–22
Setting the Valve Seat....................................... 22
Installing O-Rings, Abrasion Resistant Spring
and Cage ......................................................... 22
Installing Disc, Spring, Disc Valves and Stem...... 22
Valve Spring Options....................................22–23
Valve Disc Options............................................ 23
Pulling the Valve Seat ....................................... 23
Salvage of Worn Seats....................................... 23
Other Pump Brands .......................................... 23
Trouble Location and Remedy ..........................24–26
Parts Lists......................................................26–31
Warranty ............................................................. 32

3
MA-155L ENGINEERING DATA
Power End
Model Triplex Pump MA-155L
Maximum Input HP at Speed 155 at 450 rpm
Rated Continuous Plunger Load 9,087 lbs.
Stroke 4-1/2"
Maximum Rated Continuous Speed 450 rpm
Normal Continuous Speed Range 150 to 420 rpm
Minimum Speed 100 rpm
Oil Capacity 22 U.S. Quarts
Viscosity, S.S.U. at 210ºF 70 to 84
Power End Oiling System Splash
Power Frame, One Piece Cast Iron
Crosshead, Full Cylindrical Cast Iron
Crosshead, Diameter x Length 5-3/4" x 6-3/16"
Crankshaft Ductile Iron
Crankshaft Diameters:
At Drive Extension
At Tapered Roller Bearings
At Crankpin Bearings, Diameter x Length
4.500/4.499"
4-3/4"
4-1/2" x 3-3/4"
Crosshead (Wrist) Pin, Case-Hardened and Ground AISI 8620
Wrist Pin Bushing, SAE 660, Diameter x Width 2-5/8" x 3-5/8"
Main Bearings, Tapered Roller Timken
Crankpin Bearings,
Precision Automotive
Steel Backed,
Babbitt-Lined
Extension (Pony) Rod:
Diameter
Material
2-1/2"
17-4PH S.S.
Connecting Rod, Rifle Drilled Ductile Iron
Average Crosshead Speed:
At 450 rpm 338 fpm
Minimum Life Expectancy, Main Bearings, L10 60,000+hr
Liquid End
Plunger Size Range, Diameter 2-3/4" Thru 4"
Maximum Continuous Working Pressure 1,389 psi
Hydrostatic Test:
Discharge 2,175 psi
Suction Connection Size 6" ANSI
Hydrostatic Test, Suction 425 psi
Available Liquid End Materials, ASTM:
Nickel Aluminum Bronze
Forged Steel Block
B148-C955
A105
MA-155L ENGINEERING DATA
Liquid End (Continued)
Plunger Type Rokide®Stainless Steel:
Chromium Oxide-Coated 316 S.S.
Stuffing Boxes, Field-Removable and Replaceable:
Aluminum Bronze
Carbon Steel
B148-C955
1020
Packing Types Available:
Gland-loaded, Nonadjustable
Spring-loaded, Cup-Type
Spring-loaded, Braided Teflon®& Kevlar®
Spring-loaded, Garlock
Style 838
Style 120X
Style 140/141
Style 8921K
Studs, Material,
ASTM
A193 Grade B7,
Cadmium Plated
Nuts, Material, ASTM A194 Grade 2
Seals, Stuffing Boxes, Valve Covers, Cylinder Heads Buna-N
Bolting, High Strength, Heat Treated Alloy Steel
Available Valve Types:
Standard, Acetal Resin
Optional, Hardened and Lapped
Double Stem-Guided
Delrin®
17-4PH S.S.
17-4PH S.S.
Valve Seat, Liquid Passage Areas
Plate (Disc) Valves, (Delrin®or S.S.) 6.54 sq. in.
Average Liquid Velocity, 4" Plungers at 450 rpm:
Thru Seat
Suction Manifold
Discharge Manifold
10.8 fps
3.7 fps
16.1 fps
General
Overall Dimensions:
Length
Width
Height
55-3/4"
43"
22"
Approximate Weights:
With Aluminum Bronze Liquid End
With Forged Steel Liquid End
2,680 lbs.
2,900 lbs.

4 5
MA-155M ENGINEERING DATA
Power End
Model Triplex Pump MA-155M
Maximum Input HP at Speed 155 at 450 rpm
Rated Continuous Plunger Load 9,087 lbs.
Stroke 4-1/2"
Maximum Rated Continuous Speed 450 rpm
Normal Continuous Speed Range 150 to 420 rpm
Minimum Speed 100 rpm
Oil Capacity 22 U.S. Quarts
Viscosity, S.S.U. at 210ºF 70 to 84
Power End Oiling System Splash
Power Frame, One Piece Cast Iron
Crosshead, Full Cylindrical Cast Iron
Crosshead, Diameter x Length 5-3/4" x 6-3/16"
Crankshaft Ductile Iron
Crankshaft Diameters:
At Drive Extension
At Tapered Roller Bearings
At Crankpin Bearings, Diameter x Length
4.500/4.499"
4-3/4"
4-1/2" x 3-3/4"
Crosshead (Wrist) Pin, Case-Hardened and Ground AISI 8620
Wrist Pin Bushing, SAE 660, Diameter x Width 2-5/8" x 3-5/8"
Main Bearings, Tapered Roller Timken
Crankpin Bearings,
Precision Automotive
Steel Backed,
Babbitt-Lined
Extension (Pony) Rod:
Diameter
Material
2-1/2"
17-4PH S.S.
Connecting Rod, Automotive Type Ductile Iron
Average Crosshead Speed:
At 450 rpm 338 fpm
Minimum Life Expectancy, Main Bearings, L10 60,000+hr
Liquid End
Plunger Size Range, Diameter 1-3/4" Thru 2-3/4"
Maximum Continuous Working Pressure 3,430 psi
Hydrostatic Test:
Discharge 5,400 psi
Discharge Connection Size 6" ANSI 1500
Suction Connection Size 8" ANSI 150
Hydrostatic Test, Suction 425 psi
Available Liquid End Materials, ASTM:
Nickel Aluminum Bronze
Forged Steel Block
B148-C955
A105
MA-155M ENGINEERING DATA
Liquid End (Continued)
Plunger Type Rokide®Stainless Steel:
Chromium Oxide-Coated 316 S.S.
Stuffing Boxes, Field-Removable and Replaceable:
Aluminum Bronze
Carbon Steel
B148-C955
1020
Packing Types Available:
Gland-loaded, Nonadjustable
Spring-loaded, Cup-Type
Spring-loaded, Braided Teflon®& Kevlar®
Spring-loaded, Garlock
Style 838
Style 120X
Style 140/141
Style 8921K
Studs, Material,
ASTM
A193 Grade B7,
Cadmium Plated
Nuts, Material, ASTM A194 Grade 2
Valve Cover and
Cylinder Head Plugs
416 S.S. or
316 S.S.
Seals, Stuffing Boxes, Valve Covers Buna-N
Bolting, High Strength, Heat Treated Alloy Steel
Available Disc Valve Types:
Standard, Acetal Resin
Optional, Hardened and Lapped
Delrin®
17-4PH S.S.
Valve Set, Material, Hardened and Lapped 17-4PH S.S.
Valve Seat, Liquid Passage Areas:
Plate (Disc) Valves, (Delrin®or S.S.) 3.9 sq. in.
Average Liquid Velocity, with 2-3/4" Plungers
at 450 rpm:
Thru Seat
Suction Manifold
Discharge Manifold
8.5 fps
3.9 fps
16.9 fps
General
Overall Dimensions:
Length
Width
Height
54-3/16"
43"
22"
Approximate Weights:
With Aluminum Bronze Liquid End
With Forged Steel Liquid End
2,500 lbs.
2,700 lbs.

5
MA-155M-HD ENGINEERING DATA
Power End
Model Triplex Pump MA-155M-HD
Maximum Input HP at Speed 175 at 450 rpm
Rated Continuous Plunger Load 10,259 lbs.
Stroke 4-1/2"
Maximum Rated Continuous Speed 450 rpm
Normal Continuous Speed Range 150 to 420 rpm
Minimum Speed 100 rpm
Oil Capacity 22 U.S. Quarts
Viscosity, S.S.U. at 210ºF 70 to 84
Power End Oiling System Splash
Power Frame, One Piece Cast Iron
Crosshead, Full Cylindrical Cast Iron
Crosshead, Diameter x Length 5-3/4" x 6-3/16"
Crankshaft Forged and
Nitrided Alloy Steel
Crankshaft Diameters:
At Drive Extension
At Tapered Roller Bearings
At Crankpin Bearings, Diameter x Length
4.500/4.499"
4-3/4"
4-1/2" x 3-3/4"
Crosshead (Wrist) Pin, Case-Hardened and Ground AISI 8620
Wrist Pin Bushing, SAE 660, Diameter x Width 2-5/8" x 3-5/8"
Main Bearings, Tapered Roller Timken
Crankpin Bearings,
Precision Automotive
Steel Backed,
Babbitt-Lined
Extension (Pony) Rod:
Diameter
Material
2-1/2"
17-4PH S.S.
Connecting Rod, Automotive Type Ductile Iron
Average Crosshead Speed:
At 450 rpm 338 fpm
Minimum Life Expectancy, Main Bearings, L10 50,000+hr
Liquid End
Plunger Size Range, Diameter 1-3/4" Thru 2-3/4"
Maximum Continuous Working Pressure 3,430 psi
Hydrostatic Test:
Discharge 5,400 psi
Discharge Connection Size 6" ANSI 1500
Suction Connection Size 8" ANSI 150
Hydrostatic Test, Suction 425 psi
Available Liquid End Materials, ASTM:
Nickel Aluminum Bronze
Forged Steel Block
B148-C955
A105
MA-155M-HD ENGINEERING DATA
Liquid End (Continued)
Plunger Type Rokide®Stainless Steel:
Chromium Oxide-Coated 316 S.S.
Stuffing Boxes, Field-Removable and Replaceable:
Aluminum Bronze
Carbon Steel
B148-C955
1020
Packing Types Available:
Gland-loaded, Nonadjustable
Spring-loaded, Cup-Type
Spring-loaded, Braided Teflon®& Kevlar®
Spring-loaded, Garlock
Style 838
Style 120X
Style 140/141
Style 8921K
Studs, Material,
ASTM
A193 Grade B7,
Cadmium Plated
Nuts, Material, ASTM A194 Grade 2
Valve Cover and
Cylinder Head Plugs
416 S.S. or
316 S.S.
Seals, Stuffing Boxes, Valve Covers Buna-N
Bolting, High Strength, Heat Treated Alloy Steel
Available Disc Valve Types:
Standard, Acetal Resin
Optional, Hardened and Lapped
Delrin®
17-4PH S.S.
Valve Set, Material, Hardened and Lapped 17-4PH S.S.
Valve Seat, Liquid Passage Areas:
Plate (Disc) Valves, (Delrin®or S.S.) 3.9 sq. in.
Average Liquid Velocity, with 2-3/4" Plungers
at 450 rpm:
Thru Seat
Suction Manifold
Discharge Manifold
8.5 fps
3.9 fps
16.9 fps
General
Overall Dimensions:
Length
Width
Height
54-3/16"
43"
22"
Approximate Weights:
With Aluminum Bronze Liquid End
With Forged Steel Liquid End
2,500 lbs.
2,700 lbs.

6 7
SC-230 ENGINEERING DATA
Power End
Model Triplex Pump SC-230
Maximum Input HP at Speed 310 at 450 rpm
Rated Continuous Plunger Load 18,320 lbs.
Stroke 4-1/2"
Maximum Rated Continuous Speed 450 rpm
Normal Continuous Speed Range 150 to 420 rpm
Minimum Speed 100 rpm
Oil Capacity 22 U.S. Quarts
Viscosity, S.S.U. at 210ºF 70 to 84
Power End
Oiling System
Pressure
Lubrication System
Power Frame, One Piece Cast Iron
Crosshead, Full Cylindrical Cast Iron
Crosshead, Diameter x Length 5-3/4" x 6-3/16"
Crankshaft Ductile Iron
Crankshaft Diameters:
At Drive Extension
At Tapered Roller Bearings
At Center Bearings
At Crankpin Bearings, Diameter x Length
4.500/4.499"
4-3/4"
9-3/8"
4-1/2" x 3-3/4"
Crosshead (Wrist) Pin, Case-Hardened and Ground AISI 8620
Wrist Pin Bushing, SAE 660, Diameter x Width 2-5/8" x 3-5/8"
Main Bearings, Tapered Roller Timken
Crankpin Bearings,
Precision Automotive
Steel Backed,
Babbitt-Lined
Extension (Pony) Rod:
Diameter
Material
2-1/2"
17-4PH S.S.
Connecting Rod, Automotive Type Ductile Iron
Average Crosshead Speed:
At 450 rpm 338 fpm
Minimum Life Expectancy, Main Bearings, L10 20,000+hr
Liquid End
Plunger Size Range, Diameter 3-1/4" Thru 4"
Maximum Continuous Working Pressure 2,208 psi
Hydrostatic Test:
Discharge 3,300 psi
Suction Connection Size 6" NPT
Hydrostatic Test, Suction 425 psi
SC-230 ENGINEERING DATA
Liquid End (Continued)
Available Liquid End Materials, ASTM:
Steel A105
Piston Type Rubber
Liners Hardened Steel
Plunger Type Rokide®Stainless Steel:
Chromium Oxide-Coated 410 S.S.
Stuffing Boxes, Field-Removable and Replaceable:
Aluminum Bronze
Carbon Steel
B148-C955
1020
Packing Types Available:
Gland-loaded, Nonadjustable
Spring-loaded, Cup-Type
Spring-loaded, Braided Teflon®& Kevlar®
Spring-loaded, Garlock
Style 838
Style 120X
Style 140/141
Style 8921K
Seals, Stuffing Boxes, Valve Covers, Cylinder Heads Buna-N
Bolting, High Strength, Heat Treated Alloy Steel
Available Valve Types:
Abrasion Resistant 17-4PH S.S.
Valve Spring Material Inconel®
Average Liquid Velocity, 4-1/2" Plungers at 450 rpm:
Suction Manifold
Discharge Manifold
3.7 fps
16.1 fps
General
Overall Dimensions:
Length
Width
Height
54-1/2"
43"
22"
Approximate Weights:
With Forged Steel Liquid End 2,900 lbs.

7
RO-261 ENGINEERING DATA
Power End
Model Quintuplex Pump RO-261
Maximum Input HP at Speed 200 at 450 rpm
Rated Continuous Plunger Load 11,750 lbs.
Stroke 4-1/2"
Maximum Rated Continuous Speed 450 rpm
Normal Continuous Speed Range 300 to 420 rpm
Minimum Speed 100 rpm
Oil Capacity 22 U.S. Quarts
Viscosity, S.S.U. at 210ºF 70 to 84
Power End Oiling System Splash
Power Frame, One Piece Cast Iron
Crosshead, Full Cylindrical Cast Iron
Crosshead, Diameter x Length 5-3/4" x 6-3/16"
Crankshaft Ductile Iron
Crankshaft Diameters:
At Drive Extension
At Tapered Roller Bearings
At Crankpin Bearings, Diameter x Length
4.500/4.499"
4-3/4"
4-1/2" x 3-3/4"
Crosshead (Wrist) Pin, Case-Hardened and Ground AISI 8620
Wrist Pin Bushing, SAE 660, Diameter x Width 2-5/8" x 3-5/8"
Main Bearings, Tapered Roller Timken
Crankpin Bearings,
Precision Automotive
Steel Backed,
Babbitt-Lined
Extension (Pony) Rod:
Diameter
Material
2-1/2"
17-4PH S.S.
Connecting Rod, Rifle Drilled Ductile Iron
Average Crosshead Speed:
At 450 rpm 338 fpm
Minimum Life Expectancy, Main Bearings, L10 60,000+hr
Liquid End
Plunger Size Range, Diameter 3-1/4" Thru 4"
Maximum Continuous Working Pressure 1,415 psi
Discharge Connection Size 3" ANSI
Hydrostatic Test, Discharge 2,125 psi
Suction Connection Size 6" ANSI
Hydrostatic Test, Suction 425 psi
Available Liquid End Materials, ASTM:
Nickel Aluminum Bronze
Stainless Steel Block
B148-C955
316 S.S.
RO-261 ENGINEERING DATA
Liquid End (Continued)
Plunger Type Rokide®Stainless Steel:
Chromium Oxide-Coated 316 S.S.
Stuffing Boxes, Field-Removable and Replaceable:
Aluminum Bronze
Stainless Steel
B148-C955
316 S.S.
Packing Types Available:
Gland-loaded, Nonadjustable
Spring-loaded, Cup-Type
Spring-loaded, Braided Teflon®& Kevlar®
Spring-loaded, Garlock
Style 838
Style 120X
Style 140/141
Style 8921K
Studs, Material,
ASTM
A193 Grade B7,
Cadmium Plated
Nuts, Material, ASTM A194 Grade 2
Seals, Stuffing Boxes, Valve Covers, Cylinder Heads Buna-N
Bolting, High Strength, Heat Treated Alloy Steel
Available Valve Types:
Standard, Acetal Resin
Optional, Hardened and Lapped
Delrin®
17-4PH S.S.
Valve Seat, Liquid Passage Areas:
Plate (Disc) Valves, (Delrin®or S.S.) 6.54 sq. in.
Average Liquid Velocity, 4" Plungers at 450 rpm:
Thru Seat
Suction Manifold
Discharge Manifold
10.8 fps
3.7 fps
16.1 fps
General
Overall Dimensions:
Length
Width
Height
55-3/4"
43"
22"
Approximate Weights:
With Aluminum Bronze Liquid End
With Stainless Steel Liquid End
2,680 lbs.
2,900 lbs.

8 9
CROSS-SECTION
Ref. No. MA-155L MA-155M MA-155M-HD SC-230 RO-261
A1 43 43 43 43 43
B1 54-1/2 53-7/8 53-7/8 – 54-1/2
B2 – 41-11/16 41-11/16 – –
B3 20-13/16 19-3/4 19-3/4 – 20-13/16
B4 11 11 11 – 11
B5 10 9-1/8 9-1/8 – 10
B6 5-1/2 6-1/2 6-1/2 – 5-1/2
(B) Discharge Connections 3" ANSI 600 FF 2" ANSI 1500 FF 2" ANSI 1500 FF – 3" ANSI 600 FF
(B) Suction Connections 6" ANSI 150 FF 4" ANSI 150 FF 4" ANSI 150 FF – 6" ANSI 150 FF
C1 – 53-15/16 53-15/16 55-1/2 –
C2 – 41-3/4 41-3/4 – –
C3 – 20-7/8 20-7/8 21-1/4 –
C4 11 11 11 11 11
C5 10 9-7/8 9-7/8 15 10
C6 5-1/2 5-1/8 5-1/8 – 5-1/2
(C) Discharge Connections 3" ANSI 600 RF 2" ANSI 1500 RF 2" ANSI 1500 RF 3" NPTF 3" ANSI 600 RF
(C) Suction Connections 6" ANSI 150 RF 4" ANSI 150 RF 4" ANSI 150 RF 6" NPTF 6" ANSI 150 RF
DIMENSIONAL DATA TABLE

9
SUCTION CONNECTION
C6
C5
C1
C2
C3
C4
DISCHARGE CONNECTION
SUCTION CONNECTION
B6
B5
DISCHARGE CONNECTION
B3
B4
B1
B2
5-3/4 TYP.
2 TYP.
4 TYP.
25
12-1/2
2-3/8
32-1/4
2-7/8
2
PUMP
CRANKSHAFT
PUMP
A1
DIMENSIONAL DRAWINGS
SUCTION CONNECTION
C6
C5
C1
C2
C3
C4
DISCHARGE CONNECTION
SUCTION CONNECTION
B6
B5
DISCHARGE CONNECTION
B3
B4
B1
B2
5-3/4 TYP.
2 TYP.
4 TYP.
25
12-1/2
2-3/8
32-1/4
2-7/8
2
PUMP
CRANKSHAFT
PUMP
A1
Cast Fluid End
SUCTION CONNECTION
C6
C5
C1
C2
C3
C4
DISCHARGE CONNECTION
SUCTION CONNECTION
B6
B5
DISCHARGE CONNECTION
B3
B4
B1
B2
5-3/4 TYP.
2 TYP.
4 TYP.
25
12-1/2
2-3/8
32-1/4
2-7/8
2
PUMP
CRANKSHAFT
PUMP
A1
Block Fluid End

10 11
INSTALLATION, OPERATION,
LUBRICATION, MAINTENANCE AND
STORAGE INSTRUCTIONS
SAFETY
Electrical power or engine must be shut off completely
before attempting service on the pump or its drive. Air
surrounding the unit to be free of toxic, flammable, or
explosive gases.
Tools needed should be planned for in advance (see
valve seat pulling instructions), and should be clean
and of adequate size. A torque-wrench will be required
to tighten connecting rod cap screws.
A properly sized and set relief valve installed in the
pump discharge system (ahead of any block valves) is
necessary to protect personnel and to avoid dangerous
overpressure. The relief valve set pressure should
be not more than 25% above the design operating
pressure and should discharge to tank or to the
atmosphere (toward the ground), and must not be
directed back to the pump suction system.
WARNING: Improper use of this equipment could result
in loss of life.
CALIFORNIA PROPOSITION 65 WARNING:
WARNING: This product and related accessories
contain chemicals known to the State of California to
cause cancer, birth defects or other reproductive harm.
STORAGE
Pumps are shipped dry from the factory. If a pump has
been in storage in a humid environment for more than
6 months the crankcase cover should be removed and
carefully examined for rust or water collected in the
power end. Flush out any evidence of rust or damage
that exists, using a light clean oil.
Pumps to be placed in extended storage should be
cleaned, repaired as needed, and completely filled to
the top with clean oil to prevent rusting. Rotate pump
monthly 4-1/2 revolutions. Plug all openings to prevent
air entry and oil leakage.
Fluid ends must be completely drained of water and
suction and discharge ports blanked off. Store pump in
a clean, dry location.
PUMP LOCATION AND PIPING DESIGN
Locate pump and driver in a clean, well drained,
ventilated, and brightly illuminated area, with adequate
working spaces around the pump to provide ample
access to fluid end, power end, and associated drive
elements. Do not expect good maintenance to result if
the pump is positioned on muddy terrain, or in a dirty,
cramped, dimly lighted area!
The supply tank(s) should be large to allow dissolved
air and other gases to escape from the liquid and allow
suspended solids to settle out before entering pump.
A system employing dams and settling chambers
is desirable.
CAUTION: All pumps should be installed level. For
mobile applications the maximum angle of intermittent
operation pumps (SC pumps) should be no more than
5 degrees in any one direction.
Pumps are not designed to withstand piping weight,
vibration, and the effects of thermal piping expansion/
contraction. Piping loads may be considerable and the
weight of all valving, dampeners, filters, and associated
forces, moments, and couples must be completely
isolated. Use flexible hoses and rigid piping supports to
isolate the pump and its driver from these effects.
SUCTION PIPING
No part of the piping system deserves more careful
planning than the suction piping system. Suction
piping must be SHORT, DIRECT, and OVERSIZE. Use
one pipe size larger than the pump suction connection.
The shorter it is, the better! 1 to 3 feet per second
suction velocity is acceptable.
Reference the following table to size a direct suction
line from a tank to a pump.
Suction Piping
4" – 6" 6" – 8"
MA-155M MA-155-L
MA-155M-HD SC-230
RO-261
Use no elbows, tees, or restricted port valves in
this line. Do not install orifice plates or positive
displacement type fluid meters in the suction line
which act as flow restrictors. Avoid the use of suction
filters, if possible. Consider filtering the liquid as
it enters the supply tank rather than as it leaves
it. The use of an eccentric reducer with the flat
side up located at the pump suction connection is
recommended. The suction line should slightly rise
from tank to pump, and loops in which air may collect
must be avoided.
The absolute pressure in a suction line may be less
than atmospheric pressure and air may be “sucked”
into the line unless all flanges and connections are
airtight and watertight. If you can see water leaking out
of a suction line when the pump is still, that may mean
air is being sucked in when the pump is running.
Suction piping should be buried beneath the frost
line, or insulated to avoid freezing in the winter. If the

11
suction line has a block valve at the supply tank, a
suitable relief valve is suggested to relieve the suction
piping from any possible dangerous overpressure from
the discharge piping system.
Suction piping is often large, heavy (especially when
filled with liquid), and tends to vibrate. Proper solid
supports are recommended. A suction hose located
near the pump will isolate these effects, protecting
the pump from the forces and moments that piping
weight creates.
New suction piping systems should be flushed free
of pipe scale, welding slag, and dirt before starting
the pump. Hydrostatic testing to detect air leaks is
advisable. Proper choice of suction hose construction is
essential to avoid collapse of the hose liner.
Install a dry type compound gauge in the suction
line near the pumps which should fluctuate evenly. If
violently pulsating, this gauge indicates that the
pump is not fully primed, or that one or more valves
are inoperative.
ACCELERATION HEAD
A characteristic of all reciprocating pumps is the
imperative need to consider the effects of acceleration
head which is a SYSTEM-related phenomenon.
Acceleration head may be considered to be the loss of
available hydraulic head (energy) in the piping system
occurring because the demand by the pump cylinders
for liquid is not smooth and even. Because the pump’s
demand for liquid is cyclical, the velocity of the liquid
in the entire suction system is not truly constant but
varies in response to the combined demand of the
reciprocating plungers. Thus, liquid in the suction
system is compelled to be accelerated and decelerated
several times during each crankshaft revolution,
depending on the number of plungers. Called
“acceleration” head, this loss of available hydraulic
head is proportional to:
(a) The speed (RPM) of the crankshaft
(b) The average liquid velocity in the piping
(c) The length of the suction piping
(d) The number of pumping chambers (triplex, etc.)
(e) The compressibility of the liquid
Thus, for a given pump, acceleration head effects may
be reduced by the use of the shortest possible suction
line, sized to reduce liquid velocity to a very low speed.
This is often more economical than the use of charge
pumps or expensive suction stabilizers.
NOTE: Charge pumps should be sized to 150% of rated
pump volume. Charge pumps need to be centrifugals,
not a positive displacement pump.
A charging pump is usually not a good substitute for a
short, direct, oversize suction line, nor is it a substitute
for the computation of available NPSH, acceleration
head, friction head, vapor pressure and submergence
effects duly considered. Required NPSHR of Myers
Aplex Series pumps depends on speed, choice of
plunger size and valve spring type. Consult Myers
Aplex Series Engineering for help with your particular
application. A full discussion of suction system losses
is given in the Standards of the Hydraulic Institute,
14th Edition.
A common design mistake is the connecting of two
(or more) reciprocating pumps to a COMMON suction
header. This is a profoundly complicated suction
system, largely not amenable to mathematical analysis,
and is frequently the cause of severe pump pounding,
vibration and early valve failures. Each pump should
be fed by its own separate, individual piping system,
free from the effects of other pump cyclical demands
for liquid.
DISCHARGE PIPING
A properly designed discharge piping system usually
prevents the need of a pulsation dampener. The most
common mistakes made in the design of the discharge
piping system are:
1. Pumping directly into a tee or header. A
“standing” wave (either audible or subaudible)
then often occurs. If flow must enter a header,
use a 45º branch lateral (or equivalent) to avoid a
reflecting surface from which sound can reflect.
2. Pumping into short radius 90º elbows. Instead,
use two 45º elbows spaced 10 or more pipe
diameters apart.
3. Pumping into a right angle choke valve.
4. Pumping into too small piping line size. Piping
should be sized to keep fluid velocity below
15 feet per second, max.
5. Pumping through an orifice plate, small venturi,
or reduced port “regular opening” valve.
6. Pumping through a quick closing valve, which can
cause hydraulic shock (water-hammer).
A good discharge piping system includes:
1. A properly sized, correctly set relief valve.
Discharge from relief valve returned to tank
(not to pump suction).
2. A full opening discharge gate or ball valve.
Avoid restricting plug valves, globe valves and
angle valves.
3. A pressure gauge with gauge dampener or
snubber. Consider a liquid filled gauge.
(Scale range to be double the normal pump
operating pressure.)
Locate the relief valve and pressure gauge ahead of
any block valve and so that the pressure in the pump

12 13
is always reflected at the relief valve. The relieving
capacity of the relief valve must exceed the capacity of
the pump to avoid excessive pressure while relieving.
Use a full size relief line.
To minimize vibration (whether hydraulic or
mechanical), discharge lines should be kept short,
direct, well supported and solidly anchored. Avoid
“dead” ends and abrupt direction changes.
BYPASS PIPING
Some designers ignore this important aspect of proper
design of pump piping systems.
A reciprocating pump, especially after maintenance of
the valves or plungers, STARTS WITH ONE OR MORE
FLUID CHAMBERS FULL OF AIR. Pumps operating on
propane, butane, or other volatile liquids START WITH
VAPOR IN THE FLUID CHAMBER(S).
Positive displacement pumps do not automatically
purge themselves of air and gas after shutdown.
For example, a quintuplex plunger pump will, after
servicing, expel the air in four of the five pump
chambers. Thus, the pressure from four of the “active”
cylinders will keep shut the discharge valve of the
“inactive”, or “air bound,” cylinder. Then, the air or
gas in this cylinder will be compressed and expanded
by its reciprocating plunger and never leave the
chamber. Similar effects occur in duplex and
triplex pumps.
To overcome these difficulties, adequate provision for
expelling the gas in the “air bound” cylinders must
be present. Common practice is to totally relieve the
pump of all discharge pressure during the start-up,
after servicing.
Consider the operational advantage of a full-sized
bypass line (return to tank) which substantially removes
discharge pressure from all cylinders during the start.
This requires a block valve on the discharge side and a
full opening bypass valve on the other side.
For economy, the bypass (to tank) can be combined
with the relief valve discharge line. This line must be
full-sized, well supported, and sloped downward to
avoid freezing in cold weather. (A frozen relief valve
line provides NO protection to either the pump or
operating personnel!)
The ability of a reciprocating pump to be “self-priming”
depends on the ratio of the swept (displaced) volume in
the cylinder to the unswept (clearance) volume at the
end of the stroke. This depends on the design of the
fluid end and on the plunger size selected.
Choice of the largest size plunger for a particular
fluid end improves this compression ratio and so
leads to “self priming”, or easy priming. Choice
of the minimum size plunger sometimes leads to
difficulties, especially with pumps that require frequent
servicing, or which handle volatile liquids, or which
contain substantial amounts of dissolved air or gas.
An automatic bypass and purging system for these
applications may be merited.
LUBRICATION
Myers Aplex Series pumps use S.A.E. 40 wt.
nondetergent oil in the crankcase. This oil requires
only a nonfoaming additive and should possess good
water separation (antiemulsion) characteristics. Such
oils are often labeled “industrial” or “turbine” quality
lubricants. If these oils are not available, a good
quality gear oil or EP oil may be substituted. See
lubrication guidelines.
In temperate climates, oil viscosity selected should
fall between 70 and 84 seconds Saybolt viscosimeter
at 210º F. In arctic service, low pour point oils
are needed.
After the first 500 hours of operation in a new pump,
drain the oil. Refill with clean, fresh oil. Thereafter,
change the oil every 1,500 hours or sooner if it
becomes contaminated with water or dirt. Fill to the
center of the sight gauge. Recheck after starting,
adding oil to center of gauge while running.
The oil capacity is 22 U.S. quarts.
V-BELT DRIVE
A properly designed, well-aligned V-belt will provide
years of reliable, economical service if properly
tensioned and kept dry, free of oil and ventilated.
Alignment is critical for long life. If the shaft axes
are not truly parallel, or if the sheave grooves are not
positioned in good alignment, some belts will carry
most of the load, resulting in their disproportionate
load share and may actually twist or turn over in the
groove. Use a straight edge across the rim of the
sheaves to detect and correct for misalignment.
After about one week of operation, new V-belts will
have stretched somewhat. The motor must be moved
on its slide base to re-establish proper belt tensioning.
Insufficient tension results in slippage, burning,
squealing (especially during starting) and shortened
belt life. Overtightening imposes excessive loads on
pump and motor bearings and can cause early shaft
fatigue failure.

13
NOTES 1) CENTERLINE OF PUMP SUCTION (INLET) TO BE SLIGHTLY HIGHER THAN CENTERLINE OF SUCTION (INLET) VALVE, SO ANY AIR IN SUCTION SYSTEM PROMPTLY REACHES THE PUMP AND IS EXPELLED. 2) SLOPE BYPASS SO LOW POINT DRAIN WILL FULLY
EMPTY RELIEF AND CHOKE VALVES AND ALL
LIQUID IN BYPASS CIRCUIT.
3) DO NOT LOCATE PIPING OR OTHER EQUIPMENT IN FRONT OF OR ABOVE PUMP LIQUID END, PREVENTING SERVICING. 4) LOCATE CHARGING PUMP AT POINT SHOWN IF A
CHARGING PUMP IS NECESSARY (AS FOR VOLATILE FLUIDS, FOR EXAMPLE).
5) IF DESIRED, A TWO-WAY MOTOR-OPERATED BYPASS
VALVE MAY BE USED RATHER THAN A MANUAL TYPE. IT SHOULD BE DESIGNED TO OPEN AUTOMATICALLY WHILE STARTING OR STOPPING.
6) FEED LINE AND BYPASS LINE SHOULD FEED
LIQUID INTO TANK BELOW MINIMUM LIQUID LEVEL.
LIQUID SUPPLY TANK
SUGGESTED PIPING SYSTEM FOR PLUNGER PUMPS
BYPASS LINE
FULL-OPENING SUCTION (INLET) LINE VALVE
LOW POINT DRAIN VALVE (SEE NOTE 2)
FLEXIBLE HOSE OR EXPANSION JOINT (SEE NOTE 7)
NEEDLE OR HARD-TRIMMED CHOKE BYPASS VALVE OPEN TO
EXPEL AIR IN PUMP PRIOR TO LOADING (SEE NOTE 5)
FULL-OPENING RELIEF VALVE OR BURST-DISC
VALVE OPENS FULLY WHEN SET PRESSURE IS REACHED
HORIZONTAL PLUNGER PUMP WITH DUAL SUCTION AND DUAL DISCHARGE CONNECTIONS (DRIVER AND FOUNDATIONS NOT SHOWN)
PRESSURE GAUGE AND BLOCK VALVE
DISCHARGE PULSATION DAMPENER (IF USED)
SUCTION PULSATION DAMPENER (IF USED)
DISCHARGE LINE (SEE NOTE 7)
FULL-OPENING DISCHARGE LINE VALVE
SWING CHECK VALVE WITH FULL-OPENING SEAT
PRESSURE RELIEF VALVE AND COLD WEATHER DRAIN (SEE NOTE 9)
CENTERLINE OF PUMP SUCTION (INLET) (SEE NOTE 1)
ECCENTRIC REDUCER WITH FLAT SIDE UP
PRESSURE GAUGE AND BLOCK VALVE
FLEXIBLE HOSE OR EXPANSION JOINT (SEE NOTE 7)
SUCTION (INLET) LINE. SEPARATE LINE REQUIREDFOR EACH PUMP IF MULTIPLE PUMPING UNITS ARE USED. SIZE OF LINE DEPENDS ON ACCELERATION HEAD FACTOR BUT MUST AT LEAST EQUAL PUMP SUCTION CONNECTION SIZE. (MINIMUM)
SEE NOTE 4
VORTEX SPLITTER AND SUPPORT
SUCTION BELL. DESIGNED FOR LOW LIQUID ENTRY VELOCITY (MAY INCLUDE FOOT VALVE IF DESIRABLE)
COMPLETELY SUBMERGED BAFFLE PLATE SEPARATING INCOMING FROM OUTGOING LIQUID
MANHOLE
MINIMUM LIQUID LEVEL
FEED LINE (SEE NOTE 6)
7) TO REMOVE PIPING STRAIN AND VIBRATION, A
FLEXIBLE HOSE, EXPANSION JOINT, OR SWIVEL JOINT PAIR SHOULD BE POSITIONED TO MINIMIZE EFFECTS OF PIPING THERMAL
EXPANSION, CONTRACTION AND PIPING WEIGHT. 8) SUCTION AND DISCHARGE PIPING MUST BE SUPPORTED AND ANCHORED. 9) TO PROTECT SUCTION SYSTEM AGAINST
HAZARD OF DISCHARGE PRESSURE ENTRY (AS WHEN PUMP IS IDLE) A SMALL RELIEF VALVE IS OFTEN CONNECTED HERE. 10) ALL SYSTEM CONPONENTS MUST HAVE ADEQUATE PRESSURE RATINGS FOR OPERATING, STARTING, AND UPSET CONDITIONS IN ORDER TO REDUCE POTENTIAL HAZARDS, PARTICULAR ATTENTION IS RECOMMENDED FOR THE SURGE CONDITION THAT WILL RESULT DOWNSTREAM OF THE RELIEF
VALVE WHEN NORMAL DISCHARGE IS BLOCKED.

14 15
Use the following table in adjusting V-belt tension:
Belt Tension at Mid-Span
Cross-Section New Belts Used Belts
“B” 5 – 6 lbs. 3-1/4 – 5 lbs.
“C” 9-3/4 – 13 lbs. 6-1/2 – 9-3/4 lbs.
“3V” 4 – 10 lbs. 3 – 7-1/2 lbs.
“5V” 17 – 30 lbs. 13 – 23 lbs.
Applying the above forces with a small spring scale,
adjust motor position to provide the following deflection
at mid-span:
Approx. Center Distance
(Span), inches
Deflection,
inches
16 1/4
22 3/8
28 7/16
32 1/2
40 5/8
48 3/4
60 15/16
Belts must be matched in pitch length. If one or
two belts are slack, when the others are correctly
tensioned, investigate for possible reasons. Correct
any misalignment or lack of matching so each belt will
transmit its load share.
Sheaves must be balanced to prevent abnormal
vibration. Balancing weights must NOT be removed.
Type “QD” sheaves must be evenly tightened on their
tapered hubs to avoid rim wobble and severe lateral
vibration. V-belts that snap and jerk will produce
abnormal vibration and loads on both pump and motor
or engine.
Run the pump several minutes at full load with belt
guard removed, observing for uneven motion on the
belt slack side, especially.
When an old V-belt drive becomes unserviceable,
replace ALL belts, not just the broken or cracked belts.
Do not operate belts on sheaves having worn, rusted,
greasy or broken grooves. Shut off power to driver
before servicing drive or pump.
WARNING: Do not operate without appropriate guards
in place.
DIRECTION OF ROTATION
Before placing pump in operation, check that
crankshaft rotation agrees with the arrows cast on top
of the power frame by briefly jogging the electric motor.
Crankshaft rotation must be clockwise as viewed from
the right side of pump.
If pump is gear driven, remember that the pinion
shaft turns opposite the crankshaft, if using a single-
reduction geared drive or in the same direction as the
crankshaft when using a planetary gear.
AUTOMATIC (SAFETY) SHUTDOWNS
Carefully check all electric shutdown devices present,
such as crankcase oil level, discharge pressure,
vibration, lubricator oil level, motor thermostat, etc.
CRANKSHAFT ASSEMBLY
GENERAL
Myers Aplex Series crankshaft suspension uses two
single-row tapered bearings, which are shim adjusted
to provide the correct running clearance.
Thorough cleaning of all components prior to assembly
is essential.
Power frame, shaft, bearings and retainer MUST be
scrupulously scrubbed with clean solvent (such as
kerosene) before starting. Remove any oil, dirt, rust and
foreign matter which might prevent the correct fit up.
Crankshaft journals are critical. Remove all burrs, rust
spots, and nicks, paying special attention to the ground
areas on which bearings and oil seals operate.
Connecting rods and crossheads must be
previously installed into CA-125M pumps before the
crankshaft assembly.
TAPERED ROLLER BEARINGS
Shaft and frame tolerances provide a tight (shrink) fit
on the shaft and in the carrier. The best way to install
the cone assembly (consists of the inner race, cage
and rollers) on the shaft is to heat the cone assembly
C.D.

15
in an electric oven for 30 minutes at 300 to 400ºF. No
more! (DO NOT heat bearings with an acetylene torch.
This ruins the bearings!) Using clean, insulated gloves,
remove the hot cone assembly from the oven, promptly
dropping it on to the shaft.
The cone assembly MUST contact the seat thrust face
(not be cocked), and the large end of the rollers MUST
be down. Do not hammer on the bearing. The soft steel
cage is easily distorted, ruining its function as a roller
separator and guide against skewing. If the cone does
not contact its thrust face properly, it must be pressed
into place using a specially machined sleeve (which
does not touch the soft steel cage). A hydraulic press is
recommended if this difficulty arises.
CUP INSTALLATION
Tapered roller bearing cup (outer races) is a press-fit in
the bearing carrier, using a hydraulic press. Cup must
be pressed into a clean carrier until the race solidly
abuts its shoulder (must not be cocked).
The tool or plate used for this must contact only the
outer end face – not on the taper.
INSTALLING CRANKSHAFT
SHIM ADJUSTMENT OF TAPERED
ROLLER BEARINGS
To provide for crankshaft thermal
expansion, sufficient shims (located
beneath bearing retainer flange) must
be installed to provide .005" to .015"
lateral end play, when shaft is cold.
A feeler gauge and a 1" micrometer
caliper are required. Install a trail
shim set on one side of the pump.
Tighten the flange bolts on this
side only.
CAUTION: Lubricate the frame bores
and the O-ring seals located in each
carrier to prevent damage during
entry. Oil the bearings.
Omitting the shim set on the opposite side, draw up
the carrier, evenly tightening its cap screws. Rotate
the crankshaft slowly by hand, seating all rollers into
running position.
Measure the gap existing between the frame face and
carrier flange. The correct thickness of the shim set to
be installed on this side equals the measure gap Plus
about .010". (No preload)
After installing above shim set, a dial indicator may be
used against the end of the shaft to confirm the shim
selection. Bump the shaft in one direction and zero
the dial indicator. Bump the shaft the opposite way. If
shimming is correct, the shaft will move laterally from
.005" to .015".
About equal shim set (totals) are required under each
carrier flange.
The recommended tightening torque for bearing
retainer 3/4"-10UNC cap screws is 211 to 257 ft. lb.
INSTALLATION OF CRANKSHAFT OIL SEAL
Insert oil seal over the end of crankshaft and position
it into the oil seal bore in the power frame of bearing
retainer. Using a rubber mallet, tap it into the bore
until the face of the seal is flush with the power frame
or bearing retainer.
DISASSEMBLY
After removing the connecting rod cap and cap bolts
(note identifying marks on each cap so each may be
later correctly reassembled onto its own rod) remove
a bearing carrier from the frame. Two jack out tapped
holes are provided in the flange of the carrier for
this purpose. Support the shaft during removal to avoid
damage.
The crankshaft may now be extracted, once all
connecting rods are moved clear. Examine the crankpin
surfaces for wear or corrosive pitting. The correct
diameters of these journals are:
Crankpin Diameter............................4.5000/4.4990"
If worn more than .010" undersize, crankshaft should
be replaced, or an attempt to salvage it may be made
at a shop well equipped to grind the crankpins which
must be fully round, chrome plated, and finish ground
to the above sizes. (Myers Aplex Series does not
perform this function.)
Crankshaft tapered roller bearings should be carefully
examined for pitting, scoring or corrosion, and replaced
as required. The cone and roller assembly is most
easily removed by first cutting away the cage using
an acetylene cutting torch. Then heat the cone (inner
SETTING TOOL
BEARING CUP
CARRIER
O-RING
GROOVE
SOLID CONTACT
HERE

16 17
race) with the shaft held vertically so cone will drop
off due to its own weight. Avoid excessive heat on the
crankshaft which tends to distort its geometry.
Cups (outer races) of tapered roller bearings may be
extracted from bearing carrier using a conventional
bearing puller tool of the automotive type (widely
available). Do not attempt to use heat on a bearing
carrier as this will result in severe distortion (out-of-
round). Replace the bearing carrier, if broken or
out-of-round.
CONNECTING ROD, CROSSHEAD,
EXTENSION ROD, CROSSHEAD PIN
AND WIPER BOX ASSEMBLY/
DISASSEMBLY
GENERAL
Myers Aplex Series connecting rod assemblies employ
precision automotive type steel backed, babbitt-lined
crankpin bearing halves which require
no shims for clearance adjustment. This pump
employs full circle (piston type) crossheads and
hardened stainless steel extension rods, which are
field replaceable.
Extension rods are provided with wrenching flats
to permit tightening of the tapered thread into the
crosshead, establishing accurate alignment while
affording easy field installation.
Before beginning the assembly all parts must be
scrupulously cleaned, removing all oil, dirt, rust, and
foreign matter which prevent proper fitting, or which
might tend to score the rubbing surfaces. Clean
and examine the power frame bores for scoring and
abnormal wear, especially wear of the lower crosshead
guide way. Hone smooth, if rough.
Measure the bores of the frame using inside
micrometers to determine abnormal frame wear if any.
Crosshead O.D.: 6.740/6.737
New Frame Bores: 6.749/6.752
Frame bores that have become worn more than .015"
must be sleeved with a cast iron liner to re-establish
correct geometry and alignment. Contact Myers Aplex
Series concerning the repair of badly worn
frame bores.
Smooth any rough corners and edges on the crosshead
skirts, using fine emery cloth. Examine and clean the
female tapered threads and wrist pin holes.
INSTALLING WRIST PIN BUSHINGS
The wrist pin bushing is precision machined
bearing bronze which is press fitted into the eye of
the connecting rod.
Bushing O.D.: 3.2525/3.2515
Connecting Rod Eye: 3.250/3.251
*MA-155 requires two bushings per crosshead.
After applying oil to the bushing O.D., use a hydraulic
press to force it home. Repeat this procedure for the
second bushing. When a bronze bushing is pressed
into place, the I.D. (bore) of the bushing is reduced
somewhat, owing to the extent of press fit. Therefore,
a clean, new wrist pin should be inserted into the
bushing bore to establish that running clearance has
been obtained. The running clearance between the
wrist pin and installed bushing is:
New Pin O.D.: 2.6875/2.6860
Installed Bushing Bore: 2.6895/2.6905
Oil Clearance ...................................... .0020/.0045"
Replacement bushings are furnished prebored by
Myers Aplex Series which usually eliminates the need
to ream the installed bushing bore. However, due to
slight variations in finishes and tolerances it sometimes
happens that more than predicted contraction of
the I.D. occurs. This occurrence results in a slight
interference which may be eliminated by lightly honing
the bore of the bronze. (NOT by reducing the pin size!)
An automotive engine repair shop usually is equipped
with power honing machines capable of smoothly
finishing the bushing bore. Bore of bushing must be
round and free of taper.
CRANKPIN BEARING
HAL
F
CRANKPIN OIL HOLE
CROSSHEAD
WRENCH FLATS
CAP
CAP BOLT
CONNECTING
ROD
WRIST PIN
BUSHING
WRIST PIN
WIPER BOX
EXTENSION ROD
OIL METERING
PLUG
2 1/4"
APPROX.
OIL METERING
PLUG
WRIST PIN
BUSHING
CROSSHEAD
BUSHING TO
BE INSTALLED
INSIDE
CROSSHEAD
O.D.

17
BOLTING THE WRIST PIN
After pressing in the two bronze bushings, the wrist
pin must be bolted to the connecting rod. Place the
connecting rod inside the crosshead and slide the wrist
pin through the crosshead and connecting rod.
The hole in the wrist pin should line up with the hole
in the connecting rod. Install the shoulder bolt through
the wrist pin and thread into connecting rod.
Torque to 25 ft. lb.
After installing the pin, carefully check the crosshead
O.D. to see if it is out-of-round. If so, a smart blow with
a rubber mallet will restore the crosshead O.D. into its
original roundness.
ORDER OF ASSEMBLY
The connecting rod/crosshead assembly is installed
BEFORE the crankshaft is installed, because the wiper
box wall bore is smaller than the crosshead O.D.
This is most easily done by setting the power frame
vertically and dropping each crosshead assembly into
its frame bore.
NOTE: The connecting rod must clear the frame bore
circle in order to introduce the crankshaft in these
models.
New Crankpin O.D.: 4.5/4.499
New Connecting Rod Bore: 4.851/4.853
Crankpins that are
worn out-of-round,
tapered, or badly
scored should either
be discarded or
perhaps salvaged by
grinding undersize,
hard chrome-plated,
and finish ground
to above diameter.
(Myers Aplex Series does not offer this service.)
Connecting rod/cap bore must be perfectly round
and within above sizes and free of taper. Discard,
if elliptical or tapered as the result of abnormal
heating. Each cap and rod is match-marked for correct
identification. Take care that each cap is reinstalled
properly with its companion rod. Bearing halves are
identical and are prevented from rotating by tongues
which fit into slots in the cap.
Check that all oil holes are clean and fully open. GRIT
is the greatest enemy of bearings, however precisely
manufactured. Hence, all surfaces must be perfectly
clean and lightly oiled prior to assembly. Remove any
burrs or sharp corners which prevent the perfect fitting
of these precision bearings. Using a torque wrench,
tighten cap bolts as follows:
Thread Size: 5/8" – 18UNC
Tightening Torque: 125-135 Ft. Lb.
Specified torque, applied to clean, well oiled threads
and bearing faces, will create tensile stresses in the
cap bolts from 90,000 to 110,000 psi, approx. and
will provide correct initial tension. Myers Aplex Series
pumps use high strength cap bolts suitable for these
initial loadings, maintained by safety wire to keep the
required tightness.
After all rods and caps are secured, slowly turn the
crankshaft to be sure no bearings are in a bind.
Using a flashlight, examine the location of each
connecting rod (eye end) within its crosshead. Rods
must not touch any crosshead boss or skirt.
CONNECTING ROD
SHANK
FRAME BORE
(CRANKSHAFT
NOT INSTALLED)
CROSS HEAD & PIN
WIPER BOX WALL
FLOOR OR
BENCH TOP
WRIST PIN
CROSSHEAD
w / BUSHING
CONNECTING
ROD WITH
BUSHING
SHOULDER
SCREW
METERING
PLUG

18 19
OIL SCOOP
This pump is provided with a bronze oil scoop which
shears off oil adhearing to the crankshaft cheek,
depositing oil on the deck above the crossheads,
assuring adequate lubrication even at low
pump speeds.
The scoop is adjustable in position, and is set lightly
in contact with the crankshaft. Secure it, tightening
the self-locking nuts securely. Note that fiber washers
are employed underneath the bolt heads, preventing oil
seepage to the outside.
WIPER BOX ASSEMBLY
GENERAL
Extension rod wiper boxes (sometimes referred to
as the diaphragm stuffing box or stripper housing
assembly) serve two important functions: retention of
crankcase oil in the power end and exclusion of dirt
and water.
Myers Aplex Series has developed a unique sealing set
which operates on a hardened and ground stainless
steel extension rod (often called “pony” rod), and a
steel baffle disc affording protection against leaking
plunger packing. The seals require no adjustment, only
correct and careful assembly.
“POLY PAK” SEAL
This seal keeps oil from leaking out of the power frame.
Developed by the Parker Seal Group, this patented rod
seal employs a soft nitrile rubber O-ring to energize a
special hard polyurethane Molythane®shell by forcing
the inner lip against the rod and the outer lip against
the housing bore, as shown.
The Poly Pak seal is inserted into its counter bore with
its lips directed toward the oil in the crankcase. (Will
NOT work if installed backward!)
MECHANICAL OIL SEAL
The oil seal is to keep contamination out of the power
frame. With the box positioned in a hydraulic press,
install the backup seal against the Poly Pak seal, with
the lips of both seals facing downward.
The mechanical seal contains a garter spring. Check
to see that this spring is still properly located and in
its position. The mechanical seal has a metal case
which serves to force the Poly Pak seal into its cavity,
energizing its lips. Apply oil lightly to the bore of the
box before pressing each seal into its counterbore.
INSERTING THE EXTENSION ROD
Insert the extension rod through the wiper seals with
the tapered thread and entering FIRST. Care should
be used in moving the extension rod through the seals
with wrenching flats entering first. Do not force! The
sharp corners on the wrenching flats may damage the
seal lips! (Resulting in oil leakage.)
With extension rod inserted through the wiper box
seals, thread the tapered threads (must be clean!) into
the tapered crosshead female threads. Firmly tighten,
applying torque to the wrenching flats only. Never
damage the extension rod ground surfaces!
Then fasten the wiper box to the power frame by
tightening the cap screws. Oil leakage between frame
face and wiper box is prevented by use of a gasket
beneath the box flange.
EXTENSION ROD
WIPER BOX
OUTER MECHANICAL SEAL
PLUNGER
TO CRANKSHAFT
POLY PAK ROD SEAL
BAFFLE PLATE
PRESS WIPER BOX
SUPPORT
OIL SCOOP
LIGHT CONTACT
HERE
CROSSHEAD
DECK
CRANKSHAFT
CHEEK POWER FRAME
EXTENSION
ROD
WRENCHING
FLAT S
WIPER
BOX TAPERED
THREADS

19
STUFFING BOX, PACKING AND
PLUNGER ASSEMBLIES
GENERAL
Myers Aplex Series pumps all feature field removable
and replaceable stuffing boxes with plungers separable
from the extension rods.
If desired, the boxes, plungers, and packing units may
be installed (or removed) as a unit assembly, permitting
service outside the pump. All boxes are retained by
four (4) studs and nuts, and are centered in the frame
bore, ensuring correct alignment.
The plungers may also be removed separately (without
box removal) to facilitate repacking. With this option,
the necessary space required to remove plunger, it is
first necessary to remove the extension rod.
SPRING LOADED PACKING
Note that the gland is screwed tightly onto the box
and contacts its face. The spring is providing all of the
initial compression and adjustment. No adjustment is
provided by the gland.
Since the force exerted by the spring is contingent on
the space provided for it, the correct lengths of all rings
are essential for good tensioning.
Spring:
A stiff Inconel®spring, which closely fits the bore of
the stuffing box, is used in this assembly. This spring is
compressed in a vise to the operating length required
plus 0.25" and tied with waxed nylon spot tie cord. The
cord is looped over the ends of the spring through the
coils and tied to maintain the length mentioned above.
Each spring is assembled into the stuffing box. Note
that the spring does not contact the plunger.
Spring-Guide Ring:
Plungers are heavy and the importance of a well-fitted
guide ring that carries this weight is often overlooked.
Discard any guide ring that becomes worn or scored, as
it will then not serve its purpose. It should fit snugly in
the box. Apply oil generously to this ring.
Spring Loaded Packing:
Three (3) rings of chevron or compression packing
are installed next. For compression packing, install
them with the skive intersections 180º apart to
discourage leaking.
Gland Ring:
This ring also fits the plunger and helps support the
plunger weight. Discard it if bore is worn, rough or out-
of-round. Lightly oil the ring before insertion. The gland
ring fits all packing.
J-STYLE STUFFING BOX & PLUNGER ASSEMBLY
(STYLES 838 & 858)
Above depicts Styles 838 and 858 packing correctly
installed with all packing lips facing TOWARD the fluid
pressure. Note that two (2) units of Styles 838 and
858 packing are positioned ahead of the lantern ring,
and one (1) unit is positioned behind it. Thus lubricant
entering the lantern ring is forced toward the pressure.
Throat Bushing:
Plungers are heavy and the importance of a well fitted
throat bushing that carries this weight is often over-
looked. Discard any throat bushing that becomes worn
or scored, as it will not then serve its purpose. It should
fit snugly in the bottom of the box. Apply oil generously
to this ring.
Styles 838 and 858 Packing:
Developed by Utex Industries, Inc., Styles 838 and
858 are a NON-adjustable type packing which depends
solely on hydraulic pressure to energize the sealing
lips. (Gland-tightening forces do NOT energize the
lips.) Tightening and hydraulic end thrust loads are
transmitted entirely through the center support portions
of each ring.
The flattened portions of the rings are large enough
to withstand overtightening. Do NOT attempt to
adjust this type packing. It should be kept thoroughly
Compression Packing
Chevron Packing
SPRING
PACKING
SPACERS
GLAND RING
GLAND RING
SPRING GUIDE
SPRING GUIDE
GLAND
RING
THROAT BUSHING
LANTERN RING
PACKING SET
PRESSURE
BAFFLE

20 21
tightened at all times. (Running it loose will ultimately
ruin the bore of the box.)
Running it loose will NOT usually cause it to drip at all,
but it can ruin the box in time.
Lightly oil each ring and the box bore and then lightly
tap in each ring separately with the rings facing
correctly. This is most easily done before installing
the plunger.
Lantern rings are provided with O.D. and I.D. reliefs
and two (or more) oil holes to allow lubricant to reach
the plunger. After the last unit of Styles 838 and 858
packing is in place, generously oil the lips of all seal
rings to ease plunger entry.
INSERTING THE PLUNGER
Apply oil liberally to plunger O.D. and lightly tap it
through the packing. When introducing the plunger
through the MA-155M stuffing boxes, also apply oil
liberally to the O.D. of each extension rod to allow easy
passage through the wiper box seals.
A soft rubber mallet is recommended to avoid any
damage to the plunger face or its threads. Remember:
The fragile nature of packing rings and plunger
surfaces deserves your respect and avoidance of
careless damage to these key elements!
INSTALLING THE GLAND
Considerable downward pressure on the gland is
required to compress the spring, to move the packing
into location, and to start the threads of the box.
Once the gland threads are started, screw it down
completely until it makes up tightly against the face of
the box, for spring loaded packing. For Hi/Lo, J-Style
or Gland adjusted packing, tighten the gland until it is
seated firmly against the packing.
INSTALLING THE STUFFING BOX
Myers Aplex Series stuffing
boxes derive their alignment
from the bores of the power
frame and the faces of
the fluid end. So these
surfaces MUST be cleaned
of rust, scale, and dirt before
assembly is begun. Wash
all contacting surfaces with
clean solvent and dry with a
CLEAN shop towel.
A nitrile rubber seal is used
to seal between the face of
the fluid end (must be flat,
clean and smooth) and the face of the box. Replace if
damaged.
All stuffing boxes are retained by four large studs and
nuts which extend through the power end, serving to
clamp the box and the power frame tightly against the
fluid end face. These four stud nuts must be
EVENLY tightened.
Using a socket, socket extension, and torque wrench,
tighten clean, well-oiled threads and nut faces.
Stud Threads
1-1/4" – 8UN at
900–950 Ft. Lb.
1" – 8UN at
350–400 Ft. Lb.
SC-230 RO-261
MA-155L
MA-155M
MA-155M-HD
CONNECTING THE PLUNGER
Install the metal baffle plate on the extension rod
and roll the pump slowly until the extension rod male
threads just touch the mating plunger female threads.
Applying a pipe wrench to plunger knurled area,
thoroughly tighten the connection. Do NOT use a
“cheater” when connecting plunger to extension rod.
(Serves no useful purpose, and may damage
the connection!)
PRESSURE
BOTTOM ADAPTER
(HARD PHENOLIC)
SEAL RING
TOP ADAPTER
(HARD PHENOLIC)
JACK SCREW HOLES
FOR BOX REMOVAL
1
2
3
4
GLAND RING
TAP HERE-USING
RUBBER MALLET
OILED PLUNGER
STUFFING BOX
BENCH TO
P