Milton Roy MILROYAL G User manual

MILROYAL®G Pump
Instruction Manual
Manual No : 53942
Rev. : 01
Rev. Date : 05/2019

iInstruction Manual
PRECAUTIONS
The following precautions should be taken when working with metering pumps.
Please read this section carefully prior to installation.
Protective Clothing
ALWAYS wear protective clothing, face shield, safety glasses and gloves when working on or
near your metering pump. Additional precautions should be taken depending on the solution
being pumped. Refer to Safety Data Sheets for the solution being pumped.
Hearing Protection
It is recommended that hearing protection be used if the pump is in an environment where the
time- weighted average sound level (TWA) of 85 decibels is exceeded (as measured on the A
scale- slow response).
Electrical Safety
• Remove power and ensure that it remains off while maintaining pump.
• DO NOT FORGET TO CONNECT THE PUMP TO EARTH/ GROUND.
• Electric protection of the motor (Thermal protection or by means of fuses) is to correspond
to the rated current indicated on the motor data plate.
Liquid Compatibility
Verify if the materials of construction of the wetted components of your pump are
recommended for the solution (chemical) to be pumped.
Pumps Water “Primed”
All pumps are tested with water at the factory. If your process solution is not compatible with
water, ush the Pump Head Assembly with an appropriate solution before introducing the
process solution.
Plumbing and Electrical Connections
Always adhere to your local plumbing and electrical codes.
Line Depressurization
To reduce the risk of chemical contact during disassembly or maintenance, the suction and
discharge lines should be depressurized before servicing.
Over Pressure Protection
To ensure safe operation of the system it is recommended that some type of safety/pressure-
relief valve be installed to protect the piping and other system components from damage due
to over- pressure.
Lifting
This manual should be used as a guide only- Follow your company’s recommended lifting
procedures. It is not intended to replace or take precedence over recommendations, policies
and procedures judged as safe due to the local environment than what is contained herein.
Use lifting equipment that is rated for the weight of the equipment to be lifted.

ii Instruction Manual
TABLE OF CONTENTS
SECTION 1 - DESCRIPTION................................................................. 1
1.1 GENERAL ...................................................................... 1
1.2 PRINCIPLES OF OPERATION ...................................................... 1
1.3 GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.4 PRODUCT CODE ................................................................ 4
SECTION 2 - INSTALLATION ................................................................ 5
2.1 UNPACKING .................................................................... 5
2.2 SAFETY PRECAUTIONS .......................................................... 5
2.3 STORAGE ...................................................................... 5
2.3.1 Temporary Storage .............................................................. 5
2.3.2 Long Term Storage .............................................................. 5
2.3.3 Pump Drive.................................................................... 5
2.3.4 Electrical Equipment............................................................. 6
2.4 MOUNTING ..................................................................... 6
2.5 CONVERSION PROCEDURE....................................................... 6
2.6 PIPING CONNECTIONS........................................................... 6
2.6.1 NPSH Considerations............................................................ 6
2.6.2 General Piping Considerations..................................................... 7
2.6.3 Suction Piping Considerations ..................................................... 7
2.6.4 Discharge Piping Considerations ................................................... 8
2.6.5 Back Pressure Valves ............................................................ 8
2.6.6 Pulsation Dampeners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.6.7 Safety Valves .................................................................. 9
2.6.8 Check Valves .................................................................. 9
2.6.9 Shut- OFF Valves ............................................................... 9
2.7 ELECTRICAL CONNECTIONS ...................................................... 9
SECTION 3 - OPERATION ................................................................. 10
3.1 INITIAL START-UP............................................................... 10
3.1.1 Start- Up for New Pump ......................................................... 10
3.1.2 Start- Up of Pump Containing No Oil in Casing and Displacement Chamber................. 11
3.2 REFILL VALVE ADJUSTMENT ..................................................... 12
3.2.1 Relief Valve Adjustment (With an Adjustable System Back Pressure Valve). ................. 12
3.2.2 Relief Valve Adjustment (Without an Adjustable System Back Pressure Valve). ............... 13
3.3 USE OF AIR PURGE BUTTON ..................................................... 13
3.4 MANUAL CAPACITY CONTROL.................................................... 14
3.5 FILLING PUMPING SYSTEM ...................................................... 14
3.6 CAPACITY CALIBRATION ......................................................... 14

iii Instruction Manual
SECTION 4 - MAINTENANCE............................................................... 15
4.1 RECOMMENDED SPARE PARTS .................................................. 15
4.2 SHIPPING PUMPS FOR REPAIR .................................................. 15
4.3 ROUTINE PREVENTIVE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
4.3.1 Oil Replacement ............................................................... 15
4.3.2 Check Valves ................................................................. 16
4.3.3 Cleaning Fouled Check Valves .................................................... 16
4.3.4 Check Valve Replacement ....................................................... 16
4.3.5 Oil Strainer Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20
4.4 CORRECTIVE MAINTENANCE .................................................... 21
4.4.1 3- Function Hydraulic Valve....................................................... 21
4.4.2 “MARS” Valve Assembly ......................................................... 21
4.4.3 Rell Valve Assembly ........................................................... 22
4.4.4 Diaphragm Replacement ........................................................ 22
4.4.5 Removal of Pump Liquid End ..................................................... 23
SECTION 5 - TROUBLESHOOTING .......................................................... 24
5.1 SYMPTOMS & REMEDIES ........................................................ 24
SECTION 6 - PART NUMBERS.............................................................. 26
6.1 BASIC PARTS LIST- PUMP DRIVE.................................................. 26
6.2 BASIC PARTS LIST- LIQUID END................................................... 28
6.2.1 Mars Valve ................................................................... 28
6.2.2 Rell Valve ................................................................... 28
6.2.3 3- Function Valve .............................................................. 29
6.2.4 Check Valve Parts.............................................................. 29
6.2.5 PVC Liquid End ............................................................... 30
6.2.6 Metallic Liquid End ............................................................. 31
6.3 REMAINING LIQUID END PARTS .................................................. 33
LIST OF ILLUSTRATIONS
FIGURE 1. Model/Product Code ............................................................... 4
FIGURE 2. Sample Nameplate............................................................... 34
FIGURE 3. Mounting Hole Dimensions. ........................................................ 34
FIGURE 4. Typical Recommended Pump Installation Scheme ...................................... 34
FIGURE 5. Pump Drive Parts- Side View ....................................................... 35
FIGURE 6. Pump Drive Parts- Top View........................................................ 36
FIGURE 7. Liquid End- Top View.............................................................. 37
FIGURE 8. Liquid End- Cutaway View ......................................................... 38
FIGURE 9. Mars Value ..................................................................... 39
FIGURE 10. Double- Ball Check Valve Parts (1-1/4”-plastic;1-3/4, 2-1/2”-PVC & metallic).................. 40
FIGURE 11. Plastic Single- Ball Check Valve Parts: 1-3/4, 2-1/2, & 3” Plungers .......................... 40
FIGURE 12. Plastic Check Valves for 1-1/4” Plunger .............................................. 41
FIGURE 13. Metallic Check Valves for 1-1/4” Plunger.............................................. 42
FIGURE 14. PVC 4- Function Bleed Valve for 1-1/4” Plunger ........................................ 43

1Instruction Manual
1.1 GENERAL
MILROYAL®G pumps are reciprocating, chemical
dosing pumps capable of producing controlled
ows up to 130 gallons per hour (492 L/H) at
pressures up to 600 psi (41 BAR) (depending on
the model). These pumps feature the robust High
Performance Diaphragm (HPD) liquid end, which
eliminates the need for contour plates, and a
non-lost motion stroke adjustment mechanism
based on the variable eccentric principle. This non-
lost motion design substantially reduces pressure
and ow pulsations which in turn increases the
life of system components and results in a more
continuous chemical injection. It is designed
for industrial service and offers an accuracy of
±1% of 100% rated ow between 10% and 100%
of its ow range.
The High Performance Diaphragm (HPD) liquid end
combines all of the best characteristics of traditional
liquid ends into one technologically advanced
design. Its operating characteristics and simplicity
of operation make it the best liquid end to consider
rst for most metering pump applications.
Milton Roy’s HPD liquid end overcomes the
net positive suction head (NPSH) restrictions
associated with conventional disc diaphragm
metering pumps. This is accomplished by a unique
mechanically actuated rell system (MARS) that
eliminates the need for diaphragm support plates
thereby lowering pump NPSH requirements.
The MARS also does away with the need for eld
adjustment of the rell mechanism by automatically
compensating for process liquid modications.
This, combined with removable check valves,
makes the HPD an ideal choice for any process in
which downtime is critical.
The HPD features a preformed, PTFE faced
elastomer diaphragm that is compatible with a
wide range of process liquids and chemicals.
The convoluted design of this composite diaphragm
also offers extended life over conventional at disk
designs.
The HPD liquid end is particularly suitable for
pumping costly, aggressive or hazardous liquids
without leakage.
1.2 PRINCIPLE OF OPERATION
(Refer to Figure 5 Through 10)
The pump consists of two major assemblies;
the drive and the liquid end. Pump delivery is a
function of the drive’s stroke rate (strokes/minute),
plunger size and stroke length (% Capacity).
Stroke length can be adjusted while the pump is
running or stopped by turning the stroke adjustment
knob (330).
The drive motor transmits rotary motion to a
worm gear speed reduction unit (343, 50) which
in turn drives the variable eccentric crank (100).
The adjustable crank imparts reciprocating
motion to the plunger/connecting rod assembly
(60, 520, 525). The stroke length is adjusted by
changing the position of the variable eccentric
crank in the connecting rod assembly.
SECTION 1 - DESCRIPTION

2Instruction Manual
SECTION 1 - DESCRIPTION
The mechanical drive system of the pump drives
the plunger back and forth in the High Performance
Diaphragm (HPD) liquid end supplied with the
pump. At the start of a suction stroke, the plunger
moves away from the liquid end, drawing hydraulic
uid with it. As the hydraulic uid is drawn back,
the exible diaphragm (510) follows, lowering the
pressure of the process uid in the liquid end.
This pressure drop causes the ball(s) in the suction
check valve (Figure 10) to be lifted up thereby
allowing process uid to pass through the suction
line into the diaphragm head (1020). At the same
time, the pressure drop in the diaphragm head
causes the ball(s) in the discharge check valve
(Figure 10) to be pulled closed, blocking ow back
through the discharge line.
Note:
It is important that the pressure in the liquid
end remain above the vapor pressure of the
process uid during the suction stroke. If the
uid pressure drops below the vapor pressure,
cavitation will occur, negatively impacting the
performance of the pump. If you suspect the
possibility of cavitation, contact your Milton Roy
Representative for assistance.
At the end of the suction stroke, the process
reverses, beginning the discharge stroke.
Now the plunger moves forward, pushing hydraulic
uid before it. The hydraulic oil must therefore press
against the diaphragm, exing it forward and raising
the pressure of the process uid in the liquid end.
This pressure increase causes the process uid
to ow outward, forcing the discharge ball check
open and the suction ball check to seat, blocking
back ow through the suction line. The process
uid ows out of the diaphragm head and into the
discharge line. This suction/discharge action is
repeated with every stroke of the pump plunger,
and is the direct cause of the pumping action.
As the pump operates, a small quantity of hydraulic
oil is continuously bled through the air bleed system
(970, 960, 980 in Figure 8) in the three- function
hydraulic valve (air bleed/relief/purge- Figure 8).
An additional small quantity of hydraulic oil is
also lost on every stroke through the clearance
between the plunger and displacement chamber
bore. After a while, these normal losses result in
a shortage of hydraulic oil in the displacement
chamber. When this happens, the diaphragm will
be pulled back tight against the back contoured
surface of the displacement chamber, and part of
the diaphragm will press against the Mechanically
Actuated Rell System (MARS) valve (Figure 9).
Now, when the plunger draws back, a vacuum is
created in the displacement chamber. These two
factors (diaphragm pressing against MARS valve &
vacuum in the displacement chamber) must occur
together to trigger the MARS valve.
When both of these conditions are met, the MARS
valve is forced to its rearward position, and the
poppet (760) opens, allowing hydraulic oil from
the reservoir to enter through the refill valve
(740 in Figure 8) and replenish the lost oil. In this
manner, proper hydraulic balance is constantly
maintained in the displacement chamber.

3Instruction Manual
1.3 GENERAL SPECIFICATIONS
Maximum Capacity Range 20 GPH (76 LPH) to 130 GPH (492 LPH)
Maximum Pressure Range 100 PSIG (7 Bar) to 600 PSIG (41 BAR)
Liquid End Design Hydraulically Actuated Diaphragm with Mechanically Actuated Rell
System (MARS).
Drive Design Non-Lost Motion Variable Eccentric Type.
Plunger Diameters 1-1/4”(32mm), 1-3/4”(45mm), 2-1/2”(63mm), 3”(75mm)
Liquid End Materials of
Construction PVC, 316 SS, Alloy 20.
Steady State Accuracy ±1% of 100% rated ow between 10% and 100% of rated ow
Capacity Adjustment
Micrometer (Standard): Lockable micrometer is adjustable from
0% to 100% while pump is running or stopped
Electronic (Optional): Electronic stroke length adjustment from
4-20ma input.
Temperature Limits
Ambient Limit: 130ºF Maximum
0ºF Minimum
Note: Limited by standard lubricants. Modications are available through
Applications Engineering.
Liquid Temperature Limits:
Plastic Liquid Ends: 20ºF to 140ºF
Metallic Liquid Ends: 20ºF to 190ºF
Suction Pressure Limits Minimum Internal Pressure: 3 psia (11.5 psi maximum vacuum)
Maximum Suction Pressure: 100 psig at 80ºF and below.
Lubrication Oil bath drive lubrication.
Paint Two part epoxy, yellow RAL 1018
SECTION 1 - DESCRIPTION

4Instruction Manual
SECTION 1 - DESCRIPTION
1.4 PRODUCT CODE
MILROYAL® G pumps are available in a variety of different congurations. The complete product code
is composed of the pump “model number” + “product code”. For a breakdown of the options included
in a specic pump, compare the pump model number and product code found on the pump nameplate
with the model/product code breakdown shown in Figure 1. A sample nameplate is shown in Figure 2.
MODEL NUMBER
MGH
4 5 6
Digit 4 & 5: Plunger Size Digit 6: Liquid End Material
Description Code Description Code
1-1/4”(32mm) 20 316 SS 1
1-3/4”(45mm) 28 Plastic (PVC) 2
2-1/2”(63mm) 40 Alloy 20 5
3”(75mm) 48 PVDF 7
PRODUCT CODE
7 8 9 10 11 12 13 14 15 16 17 18 19 20
Digit 7 & 8: Stroking Speed Digits 9 & 10: Motor
Description Code Description Code
173 spm 10 No motor, Flange Mount, NEMA 56C CB
120 spm 14 No motor, Flange Mount, NEMA 145TC CC
86 spm 20 No motor, Flange Mount, NEMA 182TC CD
43 spm 30 No motor, Flange Mount, IEC80, F165 Flange MD
*Note: SPM’s for 60 Hz, 1725 rpm motor
Digits 11 & 12: Capacity Adjustment Connection Digit 13 & 14: Check Valve
Description Code Description Code
Manual, Plastic micrometer knob Electronic(4-20 ma input) M2 Pipe- NPT SE
NEMA 4, 115V E1 Pipe- BSP SN
NEMA 4, 230V E2 Pipe- DN (Socket Weld) SQ
Explosion Proof, 115V EA
Explosion Proof, 230V EB
Electronic 4-20 ma input, 24 VDC EG
Digit 15 & 16: Base Diaphragm Digits 17 & 18: Rupture Detection/Double
Description Code Description Code
No Base (Standard) NN No Rupture Detection, Single Diaphragm (Standard) NN
No Base (Optional) 11 No Rupture Detection, Double Diaphragm (Optional) DD
Rupture Detection (Gauge), Double Diaphragm (Optional) C5
Rupture Detection (Gauge + NEMA 4 Pressure Switch),
DD (Opt.) SN
Rupture Detection (Gauge + Exp Pr Switch), DD (Optional) SE
Digit 19 & 20: Check Valve Type
Description Code
Note: Degassing options are available. Consult
MRC factory or representative for details
Single Ball 11
Double Ball 22
Figure 1. Model/Product Code

5Instruction Manual
SECTION 2 - INSTALLATION
2.1 UNPACKING
Pumps are shipped Free on Board (FOB) factory
or representative warehouse and the title passes to
the customer when the carrier signs for receipt of
the pump. In the event that damages occur during
shipment, it is the responsibility of the customer to
notify the carrier immediately and to le a damage
claim.
Carefully examine the shipping 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 packing list to
be sure that all items are accounted for and intact.
2.2 SAFETY PRECAUTIONS
When installing, operating, and maintaining the
MILROYAL®G pump, keep safety considerations
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 the liquid being pumped.
Be extremely careful in the presence of hazardous
substances (e.g., Corrosives, toxins, solvents,
acids, caustics, ammables etc.).
2.3 STORAGE
2.3.1 Temporary Storage (Less than 6 Months)
It is preferable to store the material under a shelter
in its original package to protect it from adverse
weather conditions. In condensing atmospheres,
follow the long term storage procedure.
2.3.2 Long Term Storage
(Longer than 6 Months)
Primary Considerations
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
surroundings 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 extent possible.
When the instructions given in this section are
completed, the equipment is to be stored sheltered/
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 and prevent capture of
moisture. Equipment should be stored 12” 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.
2.3.3 Pump Drive
1. Flood the pump drive housing with a high grade
lubricating oil/rust preventative such as Mobile
Oil Corporation product “Mobilarma 524”.
Fill the housing completely to minimize air space
and water vapor condensation. After storage,
drain this material and rell the equipment to the
correct oil level with the recommended lubricant
for equipment commissioning.
2. Remove drive motor and brush all unpainted
metal surfaces with multipurpose grease
(NLGI grade 2 or 3). Store motor unattached.

6Instruction Manual
SECTION 2 - INSTALLATION
2.3.4 Electrical Equipment
1. Motors should be prepared in the manner
prescribed by their manufacturer. If information
is not available, dismount and store motors as
indicated in step 3 below.
2. Dismount electrical equipment (including
motors) from the pump.
3. For all 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.
2.4 MOUNTING
Support the pump rmly in a level position on a
solid, vibration- free foundation, preferably with
the base above oor level to protect the pump
from wash downs and to provide easier access
for service. Be sure to allow enough space around
the pump for easy access during maintenance
operations, pump adjustments, and/or oil lling or
draining procedures.
MILROYAL®G pumps are provided with mounting
holes to accommodate anchor bolts. Refer to
Figure 3 for mounting hole dimensions.
Some MILROYAL®G pumps are shipped with
motors dismounted. After anchoring pump in
position, install motor, referring to Figure 5.
To avoid damage to pump drive during
operation, make sure spring (360) provided with
pump is installed in worm shaft prior to motor
installation. Pumps installed outdoors should be
protected by a shelter.
2.5 CONVENTION PROCEDURE
A MILROYAL®G pump can, in some cases, be
converted from one liquid end plunger size or
material of construction to another. For more
information on converting between different liquid
end models, please contact the Milton Roy factory
or your local authorized representative.
2.6 PIPING CONNECTIONS
2.6.1 NPSH Considerations
The MILROYAL® G HPD liquid end is far superior
to conventional diaphragm liquid ends for suction
lift and many other NPSH- critical applications.
In these demanding applications, the patented
diaphragm and rell mechanism give this liquid
end truly exceptional performance.
For NPSH apply a 3 psia limitation (instead of
9 psia) in evaluating applications for this liquid end.
Size piping to accommodate peak instantaneous
flow. Because of the reciprocating motion of
the pump diaphragm, pump delivery follows an
approximate sine curve with a peak instantaneous
ow equal to pi (3.14) times the average ow.
Therefore, piping must be designed for a ow
3.14 times the pump capacity; this means that a
pump rated for 100 gallons per hour (379 L/hr.)
requires piping sufcient for 3.14 x 100 gph, or
314 gph (1188 L/hr.).
To minimize viscous ow losses when handling
viscous liquids, it may be necessary to use suction
piping up to four times larger than the size of
the suction connection on the pump. If in doubt,
contact your nearest Milton Roy representative to
determine the necessary pipe size.

7Instruction Manual
SECTION 2 - INSTALLATION
2.6.2 General Piping Considerations
1. Use extreme care in piping to plastic liquid
end pumps with rigid pipe such as PVC. If any
stresses or vibration are unavoidable, exible
connections are recommended.
2. Use piping materials that will resist corrosion by
the liquid being pumped. Use care in selecting
materials to avoid galvanic corrosion at pump
liquid end connections.
3. Use piping heavy enough to withstand maximum
pressures.
4. Remove burrs, sharp edges, and debris from
inside piping. Blow out all pipelines before
making nal connections to pump.
5. Because vapor in the liquid end will cause
inaccurate pump delivery, piping should be
sloped down to pump suction check valve to
prevent vapor pockets.
6. When pumping suspended solids (such as
slurries), install plugged crosses at all 90° line
turns to permit line cleaning without dismantling
piping.
7. See Figure 4 for a typical recommended pump
installation scheme.
2.6.3 Suction Piping Considerations
1. It is preferable to have the suction of the pump
ooded by locating the liquid end below the
lowest level of the liquid in the supply tank.
Installing the supply vessel on the suction line
in close proximity to the pump will help ensure
a ooded suction line.
2. Avoid negative suction pressure conditions
(suction lift), as such conditions adversely
affect metering accuracy. A lift of 20 Ft. of water
column straight out of a supply tank is the
maximum suction lift permissible.
3. MILROYAL®G pumps are intended to be
operated with process liquid supplied at or
above atmospheric pressure. Although these
pumps can move liquids supplied at less
than atmospheric pressure, in these negative
pressure applications it is important that all
connections be absolutely drip free and vacuum
tight.
4. When pumping a liquid near its boiling point,
provide enough suction head to prevent the
liquid from “ashing” into vapor when it enters
the pump liquid end on the suction stroke.
5. If possible use metal or plastic tubing for the
suction line because such tubing has a smooth
inner surface and can be formed into long,
sweeping bends to minimize frictional flow
losses.
6. A strainer should be used in the suction line to
prevent foreign particles from entering the liquid
end. This and any other measures to prevent
debris from entering and fouling the ball-checks
will give increased maintenance-free service.
Check strainer frequently to prevent blockage
which could lead to cavitation.
7. Keep suction piping as short and straight as
possible.
8. Piping size should be one or two sizes larger
than the liquid end suction tting to prevent
pump starvation.
9. If long suction lines are unavoidable, install a
stand pipe or suction accumulator dampener
near the pump in the suction line.
10. Suction piping must be absolutely airtight to
ensure accurate pumping. After installation,
test suction piping for leaks with air and soap
solution.

8Instruction Manual
SECTION 2 - INSTALLATION
2.6.4 Discharge Piping Considerations
1. Install pipe large enough to prevent excessive
pressure losses on the discharge stroke of the
pump. Maximum pressure at the discharge
tting on the liquid end must be kept at or below
the rated pressure (Max. allowable working
pressure shown on the pump nameplate).
2. The pump will not deliver a controlled ow unless
the discharge line pressure is 35 psi greater than
the suction line pressure. There are a number of
ways to create an articial pressure, such as by
installing a back pressure valve. (Please contact
Milton Roy for recommendations to increase
back pressure in slurry applications.)
3. When pumping water-treatment chemicals
directly into boiler drums, use one liquid
end assembly for each boiler drum.
Discharging into a manifold having the slightest
pressure difference between its several
discharge connections can diminish metering
accuracy as the outlet with the lowest pressure
will receive more liquid than the outer outlets.
2.6.5 Back Pressure Valves
A Milton Roy Back Pressure Valve should be
installed in the discharge line near the pump to
ensure sufficient discharge head pressure for
proper pump metering action. Normally, the valve
should be located near the pump. However, back
pressure valves for large pumps with long and
extremely small discharge lines may have to
be installed near the point of discharge into the
process (to minimize siphoning tendencies).
2.6.6 Pulsation Dampeners
An accumulator, surge chamber, surge suppressor,
or pulsation dampener should be used with the
back pressure valve in the discharge line to
absorb the ow peaks between the pump and
the back pressure valve. Without the pulsation
dampener the valve mechanism will snap open
and closed with the surge from each pump stroke.
The pulsation dampener will allow the back
pressure valve to oscillate about a partly-closed
position, thus minimizing wear on the valve.
Discharge line pulsation dampeners offer the
further advantage of limiting the ow and pressure
variations characteristic of this kind of pump.
Installing a properly sized pulsation dampener
will improve pump performance and may reduce
system costs dramatically by permitting the
substitution of smaller piping. Please contact
Milton Roy for further information on pulsation
dampeners.

9Instruction Manual
2.6.7 Pressure Relief Valve (PRV)
Maximum safety and reliability may be ensured by
protecting liquid ends and piping with an external
pressure relief valve installed in the system
discharge line. Although the pump is protected
against excessive pressure by an internal relief
valve, to prevent a blocked discharge line from
causing damage to the piping or process equipment,
install a Milton Roy pressure relief valve in the pump
discharge line. This valve is designed and sized to
handle system ow rates and pressures safely
while resisting corrosion by the process liquid.
Install the safety valve in the discharge line
between the pump and the nearest shut- OFF
valve. (This will prevent potential system damage
from accidental valve closure.) Pipe the pressure
relief valve outlet back to the suction tank or to
drain, but in either case ensure that the pipe end
is continuously visible so pressure relief valve
leakage may be detected. Milton Roy pressure
relief valve must be installed in accordance with its
user manual top of supply tank in order to function
properly.
2.6.8 Check Valves
A check valve should be installed at the point
where the discharge line enters a boiler or other
high-pressure vessel. This will prevent back ow
through the discharge piping and will isolate the
pump discharge from system pressures (a safety
consideration).
2.6.9 Shut- OFF Valves
In order to isolate the pump during maintenance,
provide shut- OFF valves in both suction and
discharge lines next to the pump. Locate discharge
line shut- OFF valve downstream from the inlet
connection of the safety valve. Figure 4 shows
recommended valve locations.
2.7 ELECTRICAL CONNECTIONS
Ensure that the electrical supply matches the pump
motor nameplate characteristics. Before operating
the pump, check the direction of rotation of the
motor to be sure it matches the direction of the
arrow stamped on the motor (rotation should be
clockwise when viewed from the top of the motor).
If motor rotation is incorrect, refer to the motor
data plate or motor manufacturer’s instructions
for reversing.
OPERATION WITH THE WRONG
MOTOR ROTATION WILL DAMAGE
THE PUMP AND MOTOR AND VOID THE WARRANTY.
DO NOT FORGET TO CONNECT
THE PUMP TO AN EARTH
GROUND!
Electric protection of the motor (fuses, overload
meters or relays) should correspond to the rated
current indicated on the motor data plate.
SECTION 2 - INSTALLATION

10 Instruction Manual
SECTION 3 - OPERATION
3.1 INITIAL START- UP
Check that all mounting bolts are tight, piping is
installed properly, and the discharge line is open.
Check oil drain plug for tightness. Remove the
orange oil ll cap and ll the pump casing until
level is between the top two marks on the oil cap
dipstick. (approximately 3-1/2 quarts). DO NOT
OVERFILL ABOVE TOP DASH!
Note:
The oil furnished with the pump is grade AGMA
No. 5 EP with a viscosity of 1000 SSU at 100°F
(218.4 cSt at 40°C). For operation in ambient
temperatures below 50°F (10°C), substitute
AGMA No. 2 EP with a viscosity of 400 SSU
at 100°F (86.4 cSt at 40°C). Manufacturers’
equivalent oils are shown below.
DO NOT START UP PUMP DRIVE
MOTOR BEFORE FILLING GEAR
BOX WITH OIL OR SERIOUS DAMAGE WILL OCCUR.
ABOVE 50°F:
Chevron N.L. Gear Compound
220
Exxon Spartan E.P. 220
Mobil Mobilgear 630
Texaco Meropa 220
BELOW 50°F:
Chevron N.L. Gear Compound 68
Exxon Spartan E.P. 68
Mobil Mobilgear 626
Texaco Meropa 68
Shell Omaha 68
Food Grade
Alteration Nevastane EP220
3.1.1 Start- Up for New Pump
For pumps received from the factory, the
displacement chamber (600) is already lled with
oil. Simply remove the orange oil ll cap from the
pump casing and ll the casing with the specied
oil to a level between the top two dashes on the
dipstick. DO NOT OVERFILL ABOVE TOP DASH!
Pump is now ready for operation. Operation of
the air purge button may be required to remove
air that may have come out of solution from the
oil during shipment and storage. Refer to “USE
OF AIR PURGE BUTTON” section for operation
instructions. The integral pump relief valve is
factory adjusted according to customer specied
setting. For instructions on adjustment of the pump
relief valve please refer to the next section.
BEFORE SWITCHING ON POWER
TO THE PUMP, TURN THE
CAPACITY ADJUSTMENT KNOB TO ZERO. CHECK THAT ALL
SHUT- OFF VALVES IN THE SUCTION AND DISCHARGE LINES
ARE OPEN BEFORE INCREASING THE CAPACITY
ADJUSTMENT FROM ZERO.

11Instruction Manual
3.1.2 Start- Up of Pump Containing No Oil
in Casing and Displacement Chamber
The following instructions assume that both the
pump casing and liquid end (displacement chamber)
contain no oil. This condition typically exists when
the pump is subjected to annual maintenance
during which oil may be drained from the pump
casing and oil may escape from the displacement
chamber during diaphragm replacement.
New pumps received from the factory will have
an empty pump casing and a lled displacement
chamber (liquid end). Please refer to the previous
section for start- up of new pumps. After pump
casing is lled to correct oil level (between top two
dashes on oil cap dipstick), perform the following
operations before placing the pump into service.
Numbers refer to item numbers shown in assembly
drawings (Figures 7-9) located in the back of this
manual.
1. Remove hydraulic 3- function valve (refer to
Figure 8):
a. Remove relief valve cap piece (850).
b. Make sure relief valve locknut (900) is tight
to maintain previous relief valve setting upon
start- up.
c. Remove purge button and relief valve
adjustment assembly by removing large
adjustment nut (910).
d. Using needle-nose pliers, remove spring
(950).
e. Using same pliers, remove relief valve poppet
by gently gripping the top of the valve body
(960).
2. Make sure pump capacity adjustment is set to
100%.
3. Fill the opening in the displacement chamber
(600) through the port uncovered by removal
of the 3- function valve in step 1 with the same
oil used to ll the pump casing. Fill the chamber
slowly, allowing air bubbles to escape, until
the oil level reaches the level of the drain tube
(640).
4. Reinstall 3- function valve:
a. Gently gripping the top of the relief valve
poppet (960) with needle-nose pliers, drop
the poppet assembly down into the empty
relief valve port.
b. Drop spring (950) back into relief valve port.
c. Make sure washer (935) is in place above
the O-ring (940) on purge stem (930) and
reinstall purge and relief valve adjustment
assembly by screwing large adjustment nut
(910) back into place. Make sure adjustment
nut (910) is tight.
d. Reinstall relief valve cap piece (850).
5. The pump is now properly lled with oil and ready
for service. If the relief valve locking nut (900)
remained tight during the above procedure, the
relief valve setting should remain unchanged.
If not, refer to next section for instructions on
how to set relief valve.
BEFORE SWITCHING ON POWER
TO THE PUMP, TURN THE CAPACITY
ADJUSTMENT KNOB TO ZERO. CHECK THAT ALL SHUT- OFF VALVES
IN THE SUCTION AND DISCHARGE LINES ARE OPEN BEFORE
INCREASING THE CAPACITY ADJUSTMENT FROM ZERO.
6. Make sure that all air has been bled from the
suction piping and pump head. This can be
accomplished by opening all suction line valves
as well as the system drain (Prime/Air Purge)
valve shown in Figure 4 and allowing uid to ow
into drain until all air has been purged. If drain
valve not present, with the pump capacity set
to 100%, operate the pump under no discharge
pressure until the entire pumping system has
been lled.
SECTION 3 - OPERATION

12 Instruction Manual
3.2 RELIEF VALVE ADJUSTMENT
All MILROYAL®G liquid ends have a built in relief
valve which allows hydraulic uid to return to the
pump casing if excessive pressure builds up in the
discharge line. This effectively stops the pump from
pumping, since the forward stroke of the piston
will not displace the hydraulic uid and force the
diaphragm to ex. During operation of the pump, a
relief condition caused by over pressurization can
easily be seen by looking through the sight glass
(630, Figure 7) for excessive oil ow from the drain
tube (640, Figure 8).
Note:
Under normal operation, a few drops of oil
should escape from the drain tube during each
pump stroke due to normal oil ow through the
air bleed ball (970, gure 8). If a stream of oil
from the drain tube is evident on each pump
stroke, the system pressure has exceeded the
pump relief valve setting and the pump is in a
relief condition.
The MILROYAL®G liquid end relief valve may be
adjusted to operating conditions by the following
procedure. Adjust the relief valve after rst installing
the pump and after any maintenance procedures.
THE PRESSURE RELIEF VALVE IS
FACTORY SET TO OPEN AT A
PRESSURE 15% OVER THE CUSTOMER SPECIFIED OPERATING
PRESSURE OR AT 15% ABOVE THE MAXIMUM PRESSURE
RATING OF THE PUMP IF NO OPERATING PRESSURE IS
SPECIFIED BY THE CUSTOMER. WHEN ADJUSTING THE VALVE
SETTING, NEVER SET THE VALVE AT A PRESSURE GREATER
THAN 15% OVER THE PUMP MAXIMUM PRESSURE RATING.
3.2.1 Relief Valve Adjustment (With an
Adjustable System Back pressure Valve).
Refer to Figures 7 & 8.
The following procedure assumes that a back
pressure valve and pressure gauge are installed
in the discharge line. If these components are not
installed, refer to next section.
1. Make sure all system shut- OFF valves are
open and that the back pressure valve is backed
out to allow for ow against zero discharge
pressure.
SECTION 3 - OPERATION
2. Start pump and set capacity at 100%. If a drain
valve is present in the discharge line, pump
process liquid to drain or other safe point to
establish proper pumping action. Close drain.
3. Slowly increase system pressure until:
a. Signicant ow is observed from the drain
tube (640, gure 8) as viewed through the
sight glass (630, gure 7) or
b. The system pressure reaches 15% over the
desired system pressure.
4. For condition (a) in step 4, if relief condition
occurs at less than 15% above desired pump
operating pressure, the relief valve setting
must be increased. Remove valve cover
(850) and increase relief valve setting by
turning the adjustment screw (890) clockwise
until only a few drops of oil escape on each
pump stroke (normal leakage past air bleed
ball-980). Increase system pressure to 15%
above desired operating pressure to verify that
pump is now in relief condition. If it is not, reduce
relief valve setting by turning adjustment screw
(890) counterclockwise until relief is observed
in sight glass drain tube at a pressure equal to
15% greater than desired operating pressure.
Lock-in relief valve setting by tightening locking
nut (900) while holding adjustment screw (890)
stationary. The relief valve is now properly
adjusted. Reinstall valve cover (850).
5. For condition (b) in step 4, the setting of the
relief valve should be reduced. Remove valve
cover (850) and turn adjustment screw (890)
counterclockwise until relief is observed in
sight glass drain tube at a pressure equal to
15% greater than desired operating pressure.
Lock-in relief valve setting by tightening locking
nut (900) while holding adjustment screw (890)
stationary. The relief valve is now properly
adjusted. Reinstall valve cover (850).

13Instruction Manual
SECTION 3 - OPERATION
3.2.2 Relief Valve Adjustment (Without an
Adjustable System Back Pressure Valve).
If no adjustable back pressure valve is present
in the discharge line, use the following simplied
procedure to check and/or set the relief valve
setting.
1. If pump is in a relief condition at normal
operating pressure, the relief valve setting
should be increased. Remove valve cover (850)
and increase relief valve setting by turning the
adjustment screw (890) clockwise until only a
few drops of oil escape on each pump stroke
(normal leakage past air bleed ball) (970).
Turn adjustment screw an additional ½ turn to
provide an adequate buffer zone. Lock-in relief
valve setting by tightening locking nut (900)
while holding adjustment screw (890) stationary.
The relief valve is now properly adjusted.
Reinstall valve cover (850).
2. If pump is not in a relief condition at normal
operating pressure, and the operator wishes
to reset the valve setting to approximately 15%
above operating pressure(recommended),
use the following procedure. Remove valve
cover (850) and decrease the relief valve
setting by turning the adjustment screw (890)
counterclockwise until a stream of oil ows
from the drain tube (640) on each pump stroke.
Now slowly turn adjustment screw clockwise
until only a few drops of oil escape on each
pump stroke (normal leakage past air bleed
ball). Turn screw an additional ½ turn to provide
an adequate buffer zone. Lock-in relief valve
setting by tightening locking nut (900) while
holding adjustment screw (890) stationary.
The relief valve is now properly adjusted.
Reinstall valve cover (850).
3.3 USE OF AIR PURGE BUTTON
Refer to Figure 7 & 8:
As with any hydraulically actuated diaphragm
pump, dissolved air will come out of solution
during normal operation which can negatively
impact pump performance if not removed
from the pump displacement chamber.
The MILROYAL® G hydraulic 3- function valve is
equipped with two mechanisms for removal of this
gas: a continuous air bleed and an air purge button.
The continuous air bleed portion of the valve is
composed of a sealed ball (970) which allows for a
controlled leakage of a few drops of oil, and any small
accumulations of evolved gas, on each pump stroke.
Larger quantities of air can be quickly removed by
pressing the spring-loaded purge button (860), until
it reaches its mechanical stop, for a few seconds.
Upon doing so, the operator will observe a stream
of oil and air escaping from the drain tube (640).
The need for use of the purge button to remove
a large quantity of air can be caused by several
factors:
1. Blocked suction line: A partially or fully blocked
suction line can create a vacuum pressure
condition in the hydraulic system which pulls
significant quantities of dissolved gas from
solution.
2. Oil Change: The recommended annual
changing of the oil in the pump drive can lead to
the presence of air pockets in the displacement
chamber (600).
3. Diaphragm Replacement: Results in signicant
loss of oil from the displacement chamber.
4. Pump Start- up After Long Idle Period: If the
pump has sat idle for a signicant time, gas
may come out of solution from the oil and collect
into pockets which can negatively impact pump
ow. Depression of the purge button will quickly
evacuate these pockets and restore the pump
to desired performance.

14 Instruction Manual
The operator should only activate the purge button
if some type of pump upset occurs such as the
above 4 examples. When activating the purge, only
press button for 2-3 seconds or until a stream of oil
owing from the drain tube (640) is seen through
the sight glass (630). Immediately after activation
of the purge button, a temporary reduction in ow
will occur as the rell system replenishes oil lost
during the purge. However, the pump should return
to normal operation within 1 to 2 minutes after
activation of the purge button. If after that time, the
pump ow rate is still less than it should be, repeat
the purge operation and wait another 2 minutes.
If ow has still not resumed to expected levels,
consult the troubleshooting section of this manual.
3.4 MANUAL CAPACITY CONTROL
To adjust pump capacity on standard pumps
equipped with manual stroke adjustment, first
loosen the stroke locking screw located in
the pump side cover. Pump capacity is then
adjusted by turning the micrometer-type stroke
adjustment knob clockwise to decrease capacity or
counterclockwise to increase capacity as required.
The adjustment scale is marked in percent (%)
of full stroke, with calibration lines on the knob at
1% intervals. After adjusting the knob to the desired
capacity setting, hand tighten the stroke locking
screw to maintain the capacity setting.
SECTION 3 - OPERATION
3.5 FILLING PUMPING SYSTEM
For proper pump operation, it is especially important
that pump suction and discharge lines be free of
entrained air. To ensure this condition, operate the
pump without any discharge pressure and ll the
entire pumping system with liquid before starting
pressure tests. A simple method to assure priming
of the pump is to install a tee and a shut- OFF valve
at the discharge connection of the pump.
If the pump is idle for long periods, temperature
changes in the process liquid may produce air in
the system. To discharge the air, install a valve in
the discharge line which will allow the process liquid
to be pumped to a drain when starting the pump.
3.6 CAPACITY CALIBRATION
After the rst 12 hours of operation, the pump
should be tested and calibrated to nd the exact
pump capacity under specic operating conditions
and capacity settings for the specic uid being
pumped. Typically, calibrating the pump at 100,
50, and 10 percent capacity settings is enough to
establish a pump performance curve throughout
the adjustment range.
The pump can be calibrated by measuring the
decrease in liquid level pumped from a calibrated
vessel. This method is recommended for hazardous
liquids because it eliminates operator contact
with the liquid. Milton Roy test-tube Calibration
Columns are available for convenient and accurate
calibration of any pump. The pump can also be
calibrated by collecting and measuring pumped
liquid at the pump discharge port in which case it
will be necessary to create discharge head at the
liquid takeoff point so that the pump will operate
properly. (See Section 2 for recommended ways
to do this.)
THIS METHOD IS NOT
GENERALLY RECOMMENDED
AS IT MAY EXPOSE OPERATING PERSONNEL TO HAZARDOUS
LIQUIDS.

15Instruction Manual
SECTION 4 - MAINTENANCE
4.1 RECOMMENDED SPARE PARTS
To avoid delays in repairs, a Routine Preventative
Maintenance Kit should be ordered for each pump.
The RPM kit contains an oil strainer and check
valve parts. Part orders must include the following
information:
1. Quantity required.
2. Part Number.
3. Part Description.
4. Pump serial number (found on pump
nameplate).
5. Pump model number (found on pump
nameplate).
6. Pump product code (found on pump
nameplate).
Always include the serial number, model number,
and product code in all correspondence regarding
this unit.
4.2 SHIPPING PUMPS FOR REPAIR
Pumps can not be accepted for repair without a
Return Material Authorization. Pumps should be
clearly labeled to indicate the liquid being pumped.
Process liquid should be ushed from the pump
liquid end and oil should be drained from the pump
housing and displacement chamber. To drain oil
from the displacement chamber, unscrew the rell
valve body (660, gure 8) from the displacement
chamber. Allow oil to drain into a waste container.
Remove diaphragm (510) and tilt up the back of
the pump until oil ceases to drain from the front of
the pump.
Note:
Federal law prohibits handling of equipment
that is not accompanied by an OSHA Safety
Data Sheet (SDS). A completed SDS must be
packed in the shipping crate with any pump
shipped for repair. These safety precautions will
aid the troubleshooting and repair procedure
and preclude serious injury to repair personnel
from hazardous residue in pump liquid end.
A Safety Data Sheet must accompany all
returns.
All inquiries or parts orders should be addressed to
your local Milton Roy representative or distributor.
4.3 ROUTINE PREVENTATIVE
MAINTENANCE
BEFORE ANY MAINTENANCE,
RELIEVE ALL PRESSURE
FROM SYSTEM, ISOLATE LIQUID END FROM ALL SOURCES
OF PROCESS LIQUID WITH APPROPRIATE VALVING, AND
PURGE LIQUID END OF ALL PROCESS LIQUID.
4.3.1 Oil Replacement
I n i t i a l l y , c h a n g e o i l i n p u m p c a s i n g a f t e r t h e  r s t
250 hours of operation. Then change oil after
every 4000 hours of operation or every six months
whichever comes first. Oil can be drained by
removing the drain plug (20, gure 6). When oil
has nished draining, make sure that the area
around the drain hole is clean. Screw drain plug
back in securely. Fill the pump housing with
the recommended oil until the level is between
the top two marks on the dipstick. DO NOT
OVERFILL(above top mark)! Replace the oil
ll cap and screw rmly in place. Dispose of oil
according to any federal, state or local codes which
may apply.
Note:
It is not necessary to purge the liquid end
displacement chamber of oil during annual oil
replacement.

16 Instruction Manual
4.3.2 Check Valves
Milton Roy recommends that check valve balls,
seats, gaskets, and O-rings be replaced on an
annual basis. If highly corrosive material (acids,
slurries etc.) is being pumped, some applications
may require more frequent replacement.
Milton Roy recommends an annual tune up using
a Routine Preventive Maintenance (RPM) Kit.
RPM kits contain replacements for those parts
which are subject to wear; specically the ball
checks, check valve seats, gaskets/seals, and the
strainer. Replacing these parts annually with an
RPM kit can reduce the possibility of unexpected
downtime and will help to extend pump life.
To determine if check valves need maintenance,
disassemble the check valves following the
instructions in the following “Check Valve
Replacement” section. In valves that permit
disassembly, inspect the ball check and seat for
chemical or physical damage. The ball should be
perfectly round and free of pits, marks, or scratches.
The seat should retain a smooth edge where the
ball contacts for proper sealing. If the seat edge
is worn or damaged, or has any pits, marks, or
scratches, it should be replaced. If the ball and/
or seat is excessively damaged, the replacement
schedule should be shortened accordingly.
If the ball and seat are both in good condition, the
replacement schedule can be lengthened.
BEFORE CARRYING OUT ANY
SERVICING OPERATION ON THE
METERING UNIT OR PIPES, DISCONNECT ELECTRICAL
POWER FROM THE PUMP, AND TAKE THE NECESSARY STEPS
TO ENSURE THAT THE HARMFUL LIQUID THEY CONTAIN
CANNOT ESCAPE OR COME INTO CONTACT WITH
PERSONNEL. SUITABLE PROTECTIVE EQUIPMENT MUST BE
PROVIDED. CHECK THAT THERE IS NO SYSTEM FLUID
PRESSURE BEFORE PROCEEDING WITH DISMANTLING OF
LIQUID END COMPONENTS.
4.3.3 Cleaning Fouled Check Valves
Check valve assemblies are designed to be self
cleaning and should seldom need servicing.
Fouled check valves can usually be cleaned by
pumping a solution of mild detergent and warm
water (if compatible with liquid being pumped) for
15 minutes, followed by ushing with water.
4.3.4 Check Valve Replacement
Before beginning work on the valve assemblies,
make sure the shut- OFF valves are closed and
that pressure has been bled from the system. When
replacing the valves, take care to systematically
change their O-rings and/or gaskets. Take care to
properly assemble the valve assemblies. In valves
that permit replacement of ball and seat, the ball
must be placed on the sharp edge of the seats.
For each plunger size, check valves are supplied
in three different congurations: plastic- single
ball, plastic-double ball, and metallic- double ball.
Be sure to refer to the appropriate instructional set
below pertaining to your plunger size and valve
type.
BE SURE TO FOLLOW
INSTRUCTIONS CAREFULLY
AND REFER TO THE APPROPRIATE FIGURE WHEN
REASSEMBLING CHECK VALVES. IF CHECK VALVE
CARTRIDGES ARE INSTALLED INCORRECTLY, ONE OF THE
FOLLOWING WILL OCCUR: (A) IMMEDIATE SEVERE DAMAGE
TO PUMP MECHANISM, (B) NO PUMPING, (C) REVERSE
PUMPING ACTION (FROM DISCHARGE LINE INTO SUCTION
LINE).
SECTION 4 - MAINTENANCE