Milton Roy MILROYAL D User manual

Milroyal D Disc Diaphragm
Low Flow Liquid End
INSTRUCTION
MANUAL

Issued 0810

Page L
TABLE OF CONTENTS
7DEOHRI&RQWHQWV. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L
Section 1 Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Principle of Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Safety Precautions. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Model Coding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Section 2 Storage. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Short Term Storage (Less than 6 Months). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Long Term Storage (Longer than 6 Months) . . . . . . . . . . . . . . . . . . . . . . . . . . .
Pump Drive and Gearboxes. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .
Pneumatic, Electical and Electronic Equipment. . . . . . . .. . . . . . . . . . . . . . . . . . . . . . . .
Section 3 Installation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Unpacking. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Mounting. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Liquid End Conversion Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Piping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Piping Concentrated Sulfuric Acid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Suction Lift Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 
Section 4 Operation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Initial Start-up. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
Section 2 Troubleshooting Guide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1
LIST OF ILLUSTRATIONS
Figure 1. Model Code . . . . . . . . . . . . . . . . . . . . 
Figure 2. Data Plate. . . . . . . . . . . . . . . . . . . . . .
Figure 3. Standard Dimensions. . . . . . . . . . . . . . . . . .
Figure 4. Typical Sludge Trap. . . . . . . . . . . . . . . . . .
Figure 5. Typical Installation. . . . . . . . . . . . . . . . . .
Figure 6. Milroyal D Disc Diaphragm Liquid END TOP View. . . . . . . . . . . . . . . . . .1
Figure 7. Milroyal D Disc Diaphragm Liquid END Section View. . . . . . . . . . . . . . . .1
Figure 8. Double Ball Suction & Discharge Valve (Used Before 01/01/01). . . . . . . . . . . . .
Figure 9. Single and Double Ball Check Valve Assy (Used Before 01/01/01 and 01/01/02) .2
Figure 10. Double Ball Suction & Discharge Valve (Used After 01/01/02). . . .2
Figure 11. Refill Valve Assembly . . . . . . . . . . . . . . . . . . . . . . . .2
Figure 12. Relief Valve Assembly . . . . . . . . . . . . . . . . . . . . . . .2

Page 
SECTION 1
DESCRIPTION
The instruction manual is designed to serve as a
supplement to instruction manual 339-0010-000,
which provides both general information and spe-
cific instructions for installing, operating, and main-
taining Milroyal pumps. This manual covers only
the optional Low Flow Disc Diaphragm Liquid
Ends which may be fitted to these pumps in place
of the standard Packed Plunger or HPD Liquid
Ends. Do not rely on this manual alone in
installing, maintaining, and operating Milroyal
pumps.
GENERAL
The Low Flow Disc Diaphragm Liquid End is par-
ticularly suitable for pumping costly, aggressive, or
hazardous liquids without leaking. The diaphragm
is hydraulically balanced between the process liq-
uid on one side and the hydraulic oil on the other
side. The hydraulic oil takes the place of a
mechanical connection between pump plunger
and diaphragm.
PRINCIPLE OF OPERATION
In a Disc Diaphragm Liquid End, the reciprocating
pump plunger alternately forces hydraulic oil
against the diaphragm and then draws the oil back
into the plunger bore. This action causes the
diaphragm to flex between the limiting contour
plates.
Each suction stroke of the plunger pulls the
diaphragm towards the oil side contour plate so
that process liquid flows into the displacement
chamber through the suction ball-check valve.
Each discharge stroke of the plunger pushes the
diaphragm towards the process side contour plate
to expel the process liquid from the displacement
chamber through the discharge ball-check valve.
On each suction stroke, the discharge ball-checks
are seated, and on each discharge stroke, the
suction ball-checks are seated (pressure in pump
head is greater than suction line pressure). This
mode of operation prevents back flow and ensures
liquid movement from the suction port, through the
diaphragm head, and out the discharge port.
Precise hydraulic oil volume is maintained by an
automatic air-bleed valve and a refill valve.
SAFETY PRECAUTIONS
When installing, operating, and maintaining the
Disc Diaphragm Liquid End, keep safety consider-
ations foremost. Use proper tools, protective
clothing, and eye protection when working on the
equipment and install the equipment with a view
toward ensuring safe operation. Follow the
instructions in this manual and take additional
safety measures appropriate to liquid being
pumped. Be extremely careful in the presence of
hazardous substances (e.g. corrosives, toxins,
solvents, acids, caustics, flammables, etc.)
MODEL CODING
See Figure 1 to determine the specific features
and ratings of a specific Milroyal D disc diaphragm
pump. The model code can be found on the prod-
uct data plate (see Figure 2) which is mounted on
each pump (see Figure 3)

Page 
M D D
End Item Model Code Option Select Number
Plunger Dia.
02 = 1/8”
03 = 3/16”
Liquid End
Material
1 = 316 SS
5 = Alloy 20
6 = Alloy C22
Gear Set
@1725
Code RPM
60 = 29 SPM
30 = 58 SPM
15 = 117 SPM
10 = 175 SPM
@1450
60 = 24 SPM
30 = 48 SPM
15 = 97 SPM
10 = 146 SPM
@1140
60 = 19 SPM
30 = 38 SPM
15 = 76 SPM
Motor Mount
CB = Nema 56C
Metric Mount, B5 Flange
MC = IEC 71
MD = IEC 80
ME = IEC 90
MM = Multiplex Units
Base
11=Simplex
(Standard)
1F=Simplex
(Flanged
Conn.
Connections
SE=NPT
T1=ANSI 150#
(1/2” Threaded)
S1=ANSI 150#
(1/2” Socket Welded)
Capacity Adjustment
Manual
M4=Micrometer (Aluminum)
Electronic, 4-20 mA Input
E1= Nema 4, 115 V, 60 Hz
E2= Nema 4, 220 V 60 Hz
EA= Explosion Proof, 115 V, 60Hz
EB= Explosion Proof, 220 V, 60Hz
EE= Mount, less Actuator
PRODUCT
CODE
SERIAL
NUMBER
RATED
CAPACITY
RATED
PRESSURE
FLOW CONTROL DIVISION
[phone]
WWW.MILTONROY.COM
2.25
2.00
0.13
0.13
2.25
2.00
o0.13 HOLE
4 PLCS
Figure 2. Data Plate
Figure 1. Model Code

Page 
SECTION 2
STORAGE
STORAGE
Short Term Storage (Less than 6 Months)
It is preferable to store the material under a shel-
ter in its original package to protect it from adverse
weather conditions. In condensing atmospheres,
follow the long term storage procedure.
Long Term Storage (Longer than 6 Months)
The primary consideration in storage of pump
equipment is to prevent corrosion of external and
internal components. This corrosion is caused by
natural circulation of air as temperature of the sur-
roundings change from day to night, day to day,
and from season to season. It is not practical to
prevent this circulation which carries water vapor
and other corrosive gasses, so it is necessary to
protect internal and external surfaces from their
effects to the greatest extent possible.
When the instructions given in this section are
completed, the equipment is to be stored in a shel-
ter; protected from direct exposure to weather.
The prepared equipment should be covered with a
plastic sheet or a tarpaulin, but in a manner which
will allow air circulation. Equipment should be
stored 12 inches or more above the ground.
If equipment is to be shipped directly from Milton
Roy into long term storage, contact Milton Roy to
arrange for factory preparation.
Pump Drive and Gearboxes
A. Flood the gearbox compartment with a high
grade lubricating oil/rust preventative such as
Mobile Oil Corporation product Mobilarma 524.
Fill the compartment completely to minimize air
space and water vapor condensation. After stor-
age, drain this material and refill the equipment
with the recommended lubricant for equipment
commissioning.
B. Remove drive motors and mounting adapters,
and brush all unpainted metal surfaces with multi-
purpose grease (NLGI grade 2 or 3). Store these
unattached.
Pneumatic, Electrical and Electronic
Equipment
A. Motors should be prepared in the manner pro-
scribed by their manufacturer. If information is not
available, dismount and store motors as indicated
in step “B” below.
B. For all pneumatic and electrical equipment,
place packets of Vapor Phase Corrosion Inhibitor
(VPCI) inside of the enclosure, then place the
entire enclosure, with additional packets, inside a
plastic bag. Seal the bag tightly closed. Contact
Milton Roy Service Department for recommended
VPCI materials.

Page 
Figure 3. Standard Dimensions

Page 
SECTION 3
INSTALLATION
UNPACKING
Units are shipped Ex Works , Ivyland , Pa. and the
title passes to the customer when the carrier signs
for receipt of the unit. In the event that damages
occur during shipment, it is the responsibility of the
customer to notify the carrier immediately and to
file a damage claim. Carefully examine the ship-
ping crate upon receipt from the carrier to be sure
there is no obvious damage to the contents. Open
the crate carefully so accessory items fastened to
the inside of the crate will not be damaged or lost.
Examine all material inside the crate and check
against the packing list to be sure that all items are
accounted for and intact.
MOUNTING (Refer to Figure 3)
Milroyal D pumps should be firmly mounted in a
level position on a solid foundation, preferable with
the base above floor level to protect it from wash
downs and provide easier access for service. This
model pump is provided with three tie-down points
to accommodate anchor bolts. Table-top opera-
tion is possible without need for tie-down with 1/8
or 3/16” plunger diameter liquid end. Up to six
units can be easily multiplexed to a single stan-
dard motor without special support.
LIQUID END CONVERSION:
(IF YOU PURCHASED A NEW PUMP THAT HAS
A DISC DIAPHRAGM ALREADY INSTALLED,
PROCEED TO PIPING.)
To convert a pump from standard Packed Plunger
Liquid End to Disc Diaphragm Liquid End, study
the drawings at the back of this manual and then
mount the liquid end to the pump as follows).
MILROYAL D CONVERSION STEPS (SEE
FIGURE 7
Disassembly
1. Remove Packed Plunger Liquid End
assembly from pump (see pump drive disas-
sembly instructions in instruction manual 339-
0010-000).
2. Remove plunger adapter, gland cap, gland
studs or bolts, and funnel.
Reassembly
1. Slide plunger adapter over plunger.
2. Insert plunger assembly in bore of dis-
placement chamber.
3. Carefully fit liquid end assembly to pump
housing bore while guiding plunger adapter
into threaded hole in crosshead.
4. Thread three mounting bolts into displace-
ment chamber from inside pump catchall and
tighten securely. Use pipe dope on the upper
most screw to insure a proper oil seal.
5. Bottom the plunger firmly in plunger
adapter against crosshead and then tighten
adapter securely.
6. Proceed to start-up instructions in Section
4.
PIPING
General piping instructions are given below.
Additional information is provided in pump drive
instruction manual 339-0010-000. No reciproca-
tion plunger pump can be expected to perform sat-
isfactorily unless all recommendations are fol-
lowed.
GENERAL INFORMATION
Use piping materials that are resistant to corrosion
by the liquid being pumped. Use care in selection
of materials to avoid galvanic corrosion at points of
connection to the pump liquid end.
Use piping sufficiently heavy to withstand maxi-
mum pressures.
Blow out all lines before making final connections
too pump.
Provide for pipe expansions when hot fluids are to
be pumped. Support piping so that pipe weight is
not placed on the pump. Never spring piping to
make connections.
Piping should be sloped in a manner to prevent
tapping of vapor pockets. Vapor present in liquid

end will cause inaccurate pump delivery.
SUCTION PIPING
If possible use metal or plastic tubing for the suc-
tion line because tubing has a smooth inner sur-
face and can be formed into sweep bends, thus
decreasing frictional flow losses.
Suction piping must be absolutely air tight to
insure accurate pumping. After installation, test
suction piping with air and soap solution for leaks.
A strainer should be used in the suction line to
prevent foreign particles from entering the liquid
end. Any measures which prevent foreign matter
from entering and fouling the ball checks will give
increased maintenance free service.
It is preferable to have the suction of the pump
flooding by having the liquid end located below
the level of the fluid in the supply. tank.
When pumping liquids at temperatures near the
boiling point, provide sufficient suction head to
prevent “flashing” of the liquid into vapor when it
enters the liquid end on the suction stroke.
When suction piping is long, particularly at stroke
speeds greater than 70 strokes per minute, the
size of the piping should be larger than the liquid
end suction fitting to prevent starving the pump.
Sealed piping, sufficient suction pressure, and
properly adjusted packing are absolutely neces-
sary for accurate and stable pump operation.
DISCHARGE PIPING
Install adequate size pump to prevent excessive
pressure losses on the discharge stroke of the
pump. Maximum pressure at the discharge fitting
on the liquid end must be kept at or below the
maximum pressure rating as shown on the pump
data plate. The peak flow of this type of pump
during the discharge stroke is approximately
three times the average flow rate (because of
harmonic motion of the plunger) and discharge
piping should be sized accordingly.
The pump will not deliver a controlled flow if the
discharge pressure is less than the suction pres-
sure. Piping should be arranged to provide at least
5 psi (34.5 kPa) positive pressure differential from
the discharge side to the suction side. There are a
number of ways to create an artificial discharge
pressure, such as the use of a vented riser or a
back pressure valve.
PIPING CONCENTRATED SULFURIC ACID
The liquid ends of pumps with plungers less than
5/8” in diameter, designed for 20 gph delivery or
less, are too small to tolerate the sludge in com-
mercial concentrated sulfuric acid. However, even
these pumps will serve in such applications if the
piping system is modified as follows:
1. Install a sulfuric acid tank, which has an
unused portion below the tank outlet to the suc-
tion line to collect sludge from the system.
(Maximum pressure/sludge trap is 20 psig.)
2. Ensure pump suction is flooded.
3. Use piping material identical to liquid end
material: install steel pipe to steel liquid end.
Never connect iron to steel or serious galvanic
corrosion will occur.
4. Filter sludge by installing a glass wool filter
or Milton Roy Sludge Trap in the suction line.
The first and last of these precautions will benefit
any size pump by removing the high proportion of
sludge in this acid, which can foul or clog pump
check valves.
Figure 4 illustrates a typical sludge trap and Figure
5 indicates a typical installation showing a strainer
(Sludge trap) near the tank.
SUCTION LIFT CONDITIONS
Disc Diaphragm Liquid End pumps are designed to
operate with process liquid supplied at or above
atmospheric pressure. Although these pumps can
move liquids supplied at less than atmospheric
pressure, the resulting suction lift must remain con-
stant. The intent is that the piping must be
Page 

Page 
designed to provide an adequate net positive suc-
tion head (NPSH). Obtain our NPSH Calculation
software at the Milton Roy Web site
(miltonroy.com). If assistance in determining
NPSH is needed, contact the Milton Roy
Aftermarket Service department.
Figure 4 Typical Sludge Trap
Figure 5
Typical Installation

Page 
THIS PAGE INTENTIONALLY BLANK

Page 
SECTION 4
OPERATION
INITIAL START-UP
After installing the pump perform the following
operations before placing the pump in routine
service.
Do not operate the pump without liquid in the liq-
uid end. Purge air to ensure proper operation.
A note about pump start-up time: Once the
required steps are completed and the unit is
running, patience is necessary until all air has
been removed from the hydraulic chambers
and fluid. This may take an hour or in some
cases overnight. It is helpful at the initial start-
up to relieve the discharge pressure so that
fluid and air can evacuate more easily. Once
this natural air purge occurs, the pump flow
will increase to meet the rating. Inadequate
flow, in most cases means more running time
is required until proper operation can be
achieved.
1. Connect all piping and purge air as requir-
ed.
2. Fill drive-end chamber (the end with gears
and connecting rod) to the top of the cross-
head with SHC 629 or other approved gear oil.
3. Fill the displacement chamber through
each of the three towers located on the top of
the displacement chamber with Zurnpreem
15A (or suitable) hydraulic oil. The towers con-
tain the entire volume of hydraulic oil required
to operate the diaphragm liquid end. The
towers contain the air bleed/relief valve
assembly, the hydraulic chamber vent, and the
hydraulic site glass. Each tower should oper-
ate approximately one half full during normal
operation. The sight glass and vent plugs
should remain off until after completion of initial
start up. After initial new pump start up, it is not
necessary to remove these items during sub-
sequent starting procedures.
4./oosen the oil refill valveDVV\, located under
the displacement chamber, and allow a small
amount of hydraulic oil to drain out from this
location. This will allow hydraulic oil to fill all
internal cavities. Re-tighten the oil refill valveDVV\.
Re-check the oil level in the towers. Top off if
required. It is not necessary to perform this
step after the new unit start up is completed.
The oil refill valve does not require adjustment
after initial start up, or during normal operation.
5. Purge air to ensure proper operation.
Adjust the relief valve hex-head screw counter
clockwise to relieve the pressure and allow oil
and air to flow as required during start up.
6. Check motor rotation. A pump rotation
arrow is located on the motor flange. Proper
motor rotation is required for pump operation.
Additional information regarding the operation
and start-up of the Milroyal drive can be found
in instruction manual 339-0010-000.
7. Set the micrometer pump stroke adjust-
ment knob at zero percent (0%).
8. Check to make sure that all process supply
and discharge valves are open. Inspect the
process system for leaks. Verify that all neces-
sary accessories are installed.
9. Start the pump.
WARNING:
KEEP HANDS AWAY FROM
RECIPROCATING PLUNGER,
CROSSHEAD, AND GEARS.
10. Listen for unusual noises in the drive
assembly and motor.
11. Adjust the micrometer stroke adjustment
NOTE: The catchall chamber, located between
the displacement chamber and the main drive
end, normally runs dry for the low flow disc
diaphragm design. Gear oil can carry over to
this chamber if the oil level is too high, or if the
cross-head seal leaks. Hydraulic oil can carry
over to this chamber if the plunger seal leaks, or,
if the displacement chamber sealing screws are
not installed. These ¼-20nc-1/2 screws are
located in the rear displacement chamber. To
inspect these screws, the displacement chamber
must be removed from the main drive housing.
Normally, these fasteners are installed at the
Milton Roy Company, and do not require inspec-
tion or service.

Page 1
knob to one hundred percent (100%).
12. Inspect the towers on the displacement
chamber. Hydraulic oil should be rising and
falling during the stroking sequence of the
pump. Remaining air that is trapped in the dis-
placement chamber will be purged through the
relief valve tower.
13. Slowly adjust the relief valve hex screw
clockwise until the pump begins to build pres-
sure. Normally, the pressure relief valve is fac-
tory set to open at a pressure slightly above
the pump maximum operating discharge pres-
sure. Do not set the valve at pressures greater
than 3500 PSIG.
NOTE: To adjust the relief valve first operate
the pump against a system operating pres-
sure.
1. Install a pressure gauge, with a range high-
er than the desired relief pressure at the pump
discharge connection.
2. Install a shut-off valve downstream from
the pressure gauge.
3. Set micrometer control knob to 50%
capacity.
4. Open shut off valve. Start pump; pump
process liquid to drain or other safe point to
establish proper pumping action.
WARNING:
OPERATING THE LOW FLOW DISC
DIAPHRAGM AT PRESSURES HIGHER
THAN 3500 PSIG AND A CLOSED DIS-
CHARGE LINE MAY CAUSE EQUIPMENT
DAMAGE OR BODILY HARM. CONTACT
THE Milton Roy Company IF PROPER
RELIEF VALVE ADJUSTMENT CANNOT BE
ACHIEVED.
5. Close shut off valve (“dead head” the
pump) and closely watch pressure increase on
pressure gauge.
Adjust the hydraulic relief valve hex head
screw until the proper set pressure is
achieved. If pressure exceeds desired value,
quickly open shut off valve to relieve pressure
in process line.
6. Loosen relief valve adjustment screw and
repeat step 5 until maximum pressure gauge
reading equals the relief valve pressure setting
desired.
7. After setting the relief valve, ensure shutoff
valve is fully open. Remove pressure gauge
from line, or leave in place, as desired, and
place pump in routine service.
MAINTENANCE
Hydraulic Oil:
Inspect and replace hydraulic oil on the schedule
provided.
Oil in gearbox: Mobil SHC 629.
Oil in displacement
chamber: MIL-H-5606A or ATF.
CAUTION:
Do not install check valves in the improper
direction. Install check valves with the flow
arrow pointing in the direction of process
flow (ie. suction side arrow points into the
liquid end; discharge side arrow points out
of the liquid end.
Turn check valve assemblies into liquid
end by hand. Do not overtighten, damage
to the check valves may occur.
CHECK VALVES
Maintain and service ball-check valves according
to those instructions included in manual 339-
0010-000.
Low flow disc diaphragm pumps have had several
design changes and check valves are not inter-
changeable (See table 1). Before buying RPM kits
for units in the field, contact factory service.
DISASSEMBLY
Remove and disassemble check valves as fol-
lows:
1. Unscrew check valve assembly from
diaphragm head.
2. Reassemble check valves in reverse order
from disassembly. During reassembly, tighten
cartridge assembly nuts carefully to avoid
stripping ports.

Page 1
DIAPHRAGM
Disassembly- Remove diaphragm head as fol-
lows:
1. Flush process liquid from liquid end.
2. Disconnect piping from suction and dis-
charge ball-check cartridges.
3. Remove bolts from diaphragm head and
remove head from displacement chamber.
CAUTION:
PROCESS SIDE CONTOUR PLATE AND
DIAPHRAGM RETURN BUTTON MAY
COME AWAY WITH DIAPHRAGM HEAD.
4. Remove diaphragm from displacement
chamber.
REASSEMBLY
Clean all parts for reassembly, then proceed as
follows:
DATE KIT
NUMBER NOMENCLATURE MATERIAL
Before
1/1/01 RPM037 Routine Maint. Kit, Mill D, 1/4” NPT Conn, (Female) 316SS
1/1/01 - 1/1/02 RPM038 Routine Maint. Kit, Mill D Checks, 1/4 NPT
Both Ends, (Male) 316SS
1/1/01 - 1/1/02 RPM127 Routine Maint. Kit, MIL D Double Ball 316SS
1/1/01 - 1/1/02 RPM079 Routine Maint. Kit, MDD035 AL-20, 1/4 NPT
Both Ends, (Male) AL-20
1/1/01 - 1/1/02 RPM080 Routine Maint. Kit, MDD036 HC-22, 1/4 NPT
Both Ends, (Male) HC-22
After
1/1/02 RPM130 Routine Maint. Kit, MIL D Double Ball with Face Seal 316SS
After
1/1/02 RPM190 Routine Maint. Kit, MIL D Double Ball with Face Seal AL-20
After
1/1/02 RPM191 Routine Maint. Kit, MIL D Double Ball with Face Seal HC-22
Table 1. Routine Maintenance Kits
1. Set process side contour plate in
diaphragm head. Replace spring and
diaphragm return button as shown. Set new
diaphragm in head over contour plate and but-
ton.
2. Press the diaphragm and the button to
compress spring into the diaphragm head.
Align diaphragm in shallow counter bore in the
diaphragm head.
3. Place the head flat half way across the
displacement chamber, while holding the but-
ton and diaphragm compressed. While hold-
ing the head against the displacement cham-
bers slide the head across the displacement
chamber and align bolt holes.
4. Mount diaphragm head assembly to dis-
placement chamber with six socket head bolts.
5. Tighten bolts evenly and securely to
ensure proper sealing of diaphragm. Torque to
50 ft-lbs.
6. Reconnect suction and discharge lines.
7. Test pump for leaks and then return to nor-
mal service.

THIS PAGE INTENTIONALLY BLANK
Page 1

Page 1
SECTION 5
TROUBLESHOOTING GUIDE
Pump will not operate • Liquid level is low. Add liquid.
• Blocked discharge line. Clear line.
• Liquid is frozen. Thaw liquid through pumping system.
• Fuse is blown. Replace fuse.
• Open thermal overload device
in starter. Reset device.
• Broken wire. Locate and repair.
• Low voltage. Investigate and correct (wiring may be too small).
Pump not primed. • Allow suction line and pump head to fill
with liquid before pumping against pressure.
• Air trapped in hydraulic system. Loosen air bleed/relief valve assembly and allow
excess air to escape. Re-set airbleed.
Insufficient delivery • Incorrect capacity adjustment. Readjust capacity setting.
• Incorrect pump speed. Match line voltage and frequency to pump motor
data plate.
• Trapped air in hydraulic cavities. Adjust oil relief valve counter-clockwise to remove
presssure. Repeat process of relieving pressure,
observe air, operate without pressure.
• Starved suction. Increase piping size or suction head.
• Leaky suction piping. Repair piping.
• High suction lift. Rearrange equipment to decrease lift.
• Liquid near boiling. Cool liquid or increase suction head.
• Leaky safety valve in discharge
line Repair or replace safety valve.
• High liquid viscosity. Reduce viscosity (e.g., heat or dilute liquid).
• Worn or dirty check valve seats. Clean or replace
Erratic delivery • Leaky suction piping. Repair packing.
• Leaky packing. Adjust or replace packing.
• Leaky safety valve. Repair or replace safety valve.
• Insufficient suction head. Raise suction tank level or pressurize tank.
• Liquid near boiling. Cool liquid or increase suction head.
• Worn or dirty valve seats. Clean or replace.
• Clogged or dirty line strainer. Clean strainer.
Motor overheating • Totally enclosed and explosion proof
motors run hotter than open motors.
• Wrong or insufficient gear case lub-
ricant. Check oil level and type. Replace questionable lubricant.
• Operation beyond rated capacity. Constrain operation to specifications.
• Incorrect power supply. Match line voltage and frequency to pump
motor data plate.
• Misalignment. Check alignment of moving parts.
Gear Oil in Catch-All • Gear oil level too high
Hydraulic Oil in Catch-All • Worn plunger seal.
• Displacement chamber sealing screws loose.

Page 1
FIGURE 6
MILROYAL D DISC DIAPHRAGM LIQUID END top view

Page 1
FIGURE 7
MILROYAL D DISC DIAPHRAGM LIQUID END section view

Page 1
FIGURE 6 & 7
PARTS LIST FOR LIQUID END ASSEMBLY (PLUNGER DIAMETERS 1/8” & 3/16”)
Item Description Part Number Quantity 316SS Alloy-20 Alloy-C22
0100 Screw, Socket Head 3/8-16 X 1-3/4 405-0029-154 6 X X X
0110 Washer 3/8 SAE, Plated 40476 6 X X X
0120 Spring - Diaphragm Return 20626 1 X X X
0130 Return Button, 316SS 20546 1 X
Return Button, Alloy-20 20995 1 X
Return Button, Alloy-C22 21006 1 X
0140 Process Side Contour Plate, 316SS 20569 1 X
Process Side Contour Plate, Alloy-
20 20996 1 X
Process Side Contour Plate, Alloy-
C22 21005 1 X
0150 Spring Pin 0.062x5/16 Steel 401-0001-031 2 X X X
0150 Spring Pin 0.062x5/16 18-8 SS 401-0001-033 2 X X X
0160 Diaphragm Head, Low Flow  1 X
Diaphragm Head, Alloy-20 21345 1 X
Diaphragm Head, Alloy-C22 21346 1 X
0170 Diaphragm Teflon 0.030 Thick 20550 1 X X X
0180 Contour Plate, Oil Side, Low Flow 20993 1 X X X
0190 Displacement Chamber 21001 1 X X X
0191 Sleeve 0.125 Id X 0.313 Od X 3/4 20465 1 X / 1/8 X / 1/8 X / 1/8
0191 Sleeve 0.188 Id X 0.313 Od X 3/4 20466 1 X / 3/16 X / 3/16 X / 3/16
0200 Plunger Seal, Viton 20461 1 X X X
0210 Gland Cap 304 SS 20452 1 X X X
0220/0221 1/8” Plunger and Plunger Holder 20486 1 X / 1/8 X / 1/8 X / 1/8
0220/0221 3/16” Plunger and Plunger Holder 20485 1 X / 3/16 X / 3/16 X / 3/16
0230 Floating Plunger Nut 416 SS 272-9997-017 1 X X X
0240 Thrust Washer Disc 219-9999-052 1 X X X
0250 Thrust Washer Ring 219-9998-052 1 X X X
0260 Soc Hd Scr 1/4-20x5/8 18.8 SS 405-0027-085 3 X X X
0270 Soc Hd Scr 1/4-20x1 Alloy 405-0027-111 3 X X X
0280 Flat Washer 1/4 18.8 SS 404-0005-012 3 X X X

Page 1
PARTS LIST FOR LIQUID END ASSEMBLY FIGURES 6 & 7, CONT.
Item Description Part
Number Quantity 316SS Alloy-20 Alloy-C22
0290 Sight Glass 1/2 BSP Thread 20455 1 X X X
0300 Breather Cap 1/2 NPT 20596 1 X X X
0310 Barb, Air Bleed, 316 SS 20352 1 X
Barb, Air Bleed, Alloy-20 20528 1 X
Barb, Air Bleed, Alloy-C22 21010 1 X
320 O-Ring 2-007 - 90 Durometer 40466 1 X
9001 1/4: NPT Double Ball Check Valve, Suction,
Used before 01/01/01, See Figure 8 221-9997-128 1 X
9002 1/4: NPT Double Ball Check Valve,
Discharge, Used before , See Figure 8 221-9997-228 1 X
9001/
9002
1/4: NPT Single Ball Check Valve, Used
between 01/01/01 and 01/01/02, Replaced
by 21342, See Figure 9
21082 1 X
1/4: NPT Single Ball Check Valve, Used
between 01/01/01 and 01/01/02, Replaced
by 21326, See Figure 9
21085 1 X
1/4: NPT Single Ball Check Valve, Used
between 01/01/01 and 01/01/02, Replaced
by 21343, See Figure 9
21086 1 X
1/4: NPT Single Ball Check Valve, Used
between 01/01/01 and 01/01/02, See Fig. 9 21342 1 X
1/4: NPT Double Ball Check Valve, Used
between 01/01/01 and 01/01/02, See Fig. 9 21326 1 X
1/4: NPT Double Ball Check Valve, Used
between 01/01/01 and 01/01/02, See Fig. 9 21343 1 X
9001 1/4: NPT Double Ball Check Valve, Suction,
Used After 01/01/02, See Figure 10 30733 1 X
1/4: NPT Double Ball Check Valve, Suction,
Used After 01/01/02, See Figure 10 30722 1 X
1/4: NPT Double Ball Check Valve, Suction,
Used After 01/01/02, See Figure 10 30735 1 X
9002 1/4: NPT Double Ball Check Valve, Dis-
charge, Used After 01/01/02, See Figure 10 30734 1 X
1/4: NPT Double Ball Check Valve, Dis-
charge, Used After 01/01/02, See Figure 10 30723 1 X
1/4: NPT Double Ball Check Valve, Dis-
charge, Used After 01/01/02, See Figure 10 30736 1 X

Page 
Item Number Nomenclature Part Number Quantity Material
Figure 8 1/4: NPT Double Ball Check Valve*
9001 Suction Valve Assembly 221-9997-128 1 $
9002 Discharge Valve Assembly 221-9997-228 1 $
* USED BEFORE 01/01/0186(')2566$1'$/,48,'(1'

FIGURE 8
DOUBLE BALL SUCTION & DISCHARGE VALVE
USED BEFORE 01/01/01
WARNING: IMPROPER VALVE
ASSEMBLY WILL CAUSE
EQUIPMENT DAMAGE AND
MAY CAUSE BODILY HARM.