Nova-Tech LMI Series G - SG Metering Pump User Manual

Series G Model G

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METERING
PUMP

INSTALLATION,
OPERATION, AND
MAINTENANCE
MANUAL

Please record the following data for file reference
Tag Number(s): ________________________________
Model Number: ________________________________
Serial Number: ________________________________
Installation Date: ______________________________
Installation Location: ___________________________

201 Ivyland Road

Ivyland, PA 18974
TEL: [phone]
FAX: [phone]

www.lmipumps.com

339-0089-000

ISSUED 02/2010

Precautions

For Pumps with PVC & 316SS Liquid Ends

WHEN USED IN SWIMMING POOLS OR SPAS/HOT TUBS

(ANSI/NSF 50)

1. Caution on Chemical Concentration:

!

There is a potential for elevated chemical concentration during periods of no flow, for example,
during backwash in the system. Steps, such as turning the pump off, should be taken during
operation or installation to prevent this. Contact your sales representative or distributor about
other external control options to help mitigate this risk.

2. Flow Indicating Device:

!

To ensure operation of the pump it is recommended that some type of Flow Indicating Device be
installed to measure water flow rates and be appropriate for the output of the pump. Contact your
distributor or sales representative for further information.

3. Head Loss / Over Pressure Protection / Back Pressure-Anti-Siphon Valve:

!

3.1 Milton Roy metering pumps are positive displacement. Head loss is not applicable to the
pump.

3.2 To ensure safe operation of the pump it is recommended that some type of safety/pressure­relief valve be installed to protect the piping and other system components from failing due to
excessive pressure.

3.3 If you are pumping downhill or into low or no system pressure, a back pressure/anti-siphon
device should be installed to prevent over pumping or siphoning. Contact your distributor or sales
representative for further information.

4. Additional Operation and Installation Instructions for 316SS or PVC Liquid Ends:

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4.1 Application of this pump to swimming pool/spas only evaluated to NSF/ANSI 50.

4.2 There is a potential for elevated chemical concentration during periods of no flow, for
example, during backwash in the system. Steps, such as turning the pump off, should be taken
during operation or installation to prevent this. See your sales representative or distributor about
other external control options to help mitigate this risk.

4.3 Liquid Compatibility CAUTION: Determine if the materials of construction included in the liquid
handling portion of your pump are adequate for the solution (chemical) to be pumped. 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 MSDS precautions from your solution supplier. Reference a Milton Roy Material
Selection Chart for aid in selecting appropriate material of construction for fluids of your specific
metering pump. Contact your sales representative or distributor for further information.

i

General Precautions For All Pumps

The following precautions should be taken when working with all 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 pre
to Material 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 time­weighted 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

•

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Liquid Compatibility

Verify if the materials of construction of the wetted components of your pu
solution (chemical) to be pumped.

!

Pumps Water “Primed”

All pumps are tested with water at the factory. If your process solution is n
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

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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.

!

Electric protection of the motor (Thermal protection or by means of fuses) i
the rated current indicated on the motor data plate.

cautions should be taken depending on the solution being pumped. Refer

CONNECT THE PUMP TO EARTH

s to correspond to

mp are recommended for the

ot compatible with water, flush

ii

TABLE OF CONTENTS

SECTION 1 - DESCRIPTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.1 GENERAL INFORMATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.2 PRINCIPLE OF OPERATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.3 GENERAL SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

1.4 PRODUCT CODE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

SECTION 2 - INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.1 UNPACKING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.2 SAFETY PRECAUTIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.3 STORAGE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

2.4 MOUNTING . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.5 PIPING. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2.6 LEAK DETECTION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

2.7 ELECTRICAL CONNECTIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

SECTION 3 - OPERATION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

3.1 INITIAL START-UP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

SECTION 4 - MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.1 SPARE PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.2 SHIPPING PUMPS FOR REPAIR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

4.3 PREVENTIVE MAINTENANCE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.4 CORRECTIVE MAINTENANCE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.4.1 Check Valve Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

4.4.1.1 Plastic Check Valves (PVC, PVDF, Polypropylene, & Sulfuric Acid

Service . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

4.4.1.2 Models SG6 & SG7 Liquid End - Stainless Steel Check Valves . . . . . . . . 16

4.4.1.3 Model SG5 Liquid End - Stainless Steel Check Valves . . . . . . . . . . . . . . . 17

4.4.1.4 Model SG5 Liquid End - Slurry Service Check Valves, use until

1 June 2008. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

4.4.1.5 Models SG5, SG6, & SG7 Liquid End - Slurry Service Check Valves . . . . 18

4.4.1.6 Models SG5, SG6 & SG7 Liquid End - Polymer Service Check Valves . . 18

4.4.2 Diaphragm Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

4.4.2.1 Diaphragm Removal (All types; Refer to Figures 6-13 ). . . . . . . . . . . . . . . 19

iii

TABLE OF CONTENTS (CONT.)

4.4.2.2 Disassembly (Only Those Units With a “Hex Head“

Diaphragm Cap Design) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.4.2.3 Reassembly . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

4.4.2.4 Reinstallation of Assembly (Refer to Figure 6 Through 13) . . . . . . . . . . . 19

4.4.3 Replacing Oil Seal . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

SECTION 5 - TROUBLESHOOTING GUIDE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

SECTION 5 - PARTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.1 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.2 ILLUSTRATED PARTS LIST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

6.3 DRIVE, SIDE VIEW . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

6.4 DRIVE, TOP VIEW. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

6.5 SG5 PLASTIC LIQUID END . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

6.6 SG5 METALLIC LIQUID END - STAINLESS STEEL - NPT. . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

6.7 SG6 PLASTIC LIQUID END . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

6.8 SG6 METALLIC LIQUID END - STAINLESS STEEL - NPT. . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

6.9 SG7 PLASTIC LIQUID END . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

6.10 SG7 METALLIC LIQUID END - STAINLESS STEEL - NPT. . . . . . . . . . . . . . . . . . . . . . . . . . . 42

6.11 CHECK VALVE PARTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

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THIS PAGE INTENTIONALLY BLANK

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SECTION 1

DESCRIPTION

1.1 GENERAL INFORMATION

The Series G Model G is a reciprocating, chemical
dosing pump capable of producing controlled flows
up to 310 gallons per hour (1175 L/H) at pressures
up to 150 psi (10 BAR) (depending on the model).
These pumps feature a mechanically actuated dia­phragm liquid end, which eliminates the need for
flow-restricting contour plates, and a stroke adjust­ment mechanism based on the variable eccentric
principle instead of the traditional lost-motion
design. This design substantially reduces pressure
and flow pulsations contributing to an increase in
the life of system components and more continu­ous chemical injection. It is designed for industrial
service and offers an accuracy of ±2% of 100%
rated flow between 10% and 100% of its flow
range.

1.2 PRINCIPLES OF OPERATION

The pump consists of two major assemblies; the
drive and the liquid end. Pump delivery is a func­tion of the drive’s stroke rate, liquid en d size and
stroke length. Stroke length can be adjusted while
the pump is running or stopped by turning the
stroke adjusting knob.

The drive motor transmits rotary motion to a worm
gear speed reduction unit which in turn drives the
variable eccentric crank. The adjustable crank
imparts reciprocating motion to the diaphragm
through an interposing connecting rod. The stroke
length is adjusted by changing the position of the
variable eccentric crank in the connecting rod
assembly.

As the diaphragm starts back on the suction stroke,
the pressure immediately drops inside the liquid
end. When the liquid end pressure drops below the
suction line pressure, the suction ball check is
“pushed” upward and the process fluid in the suc­tion line flows into the liquid end chamber. When
the suction stroke ends, the diaphragm movement
momentarily stops. The pressure in the liquid end
equalizes with the pressure in the suction line and
the suction ball check seats.

NOTE: It is important that the pressu re in the
liquid end remain above the vapor pressure of
the process fluid during the suction stroke. If

the fluid 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 LMI
Distributor for assistance.

As the diaphragm starts forward on the discharge
stroke the pressure immediately rises inside the
liquid end. When the liquid end pressure rises
above the discharge line pressure, the discharge
ball check is “pushed” upward and the process fluid
in the liquid end flows into the discharge line. When
the discharge stroke ends, the diaphragm momen­tarily stops again. The pressure in the liquid end
equalizes with the discharge line pressure and the
discharge ball check reset. The cycle then starts
again.

1.3 GENERAL SPECIFICATIONS
FLOW RATE:

Up to 300 GPH (1175 L/H)

PRESSURE:

Up to 150 PSIG (10 BAR)

DESIGN:

Mechanically Actuated Diaphragm

DRIVE:

Variable Eccentric

ACCURACY:

±2% of 100% rated flow between 10% and 100%
of rated flow

ADJUSTMENT:

Lockable micrometer is adjustable from 0% to
100% while pump is running or stopped

LUBRICATION:

Oil bath Over 50ºF (10ºC), Zurn EP 95, 3 1/2
qt.(3.3 liter). Below 50ºF (10ºC), Zurn EP 35

WEIGHT:

90 lb (40.8kg)

1

Figure 1. Model/Product Code.

2

1.3 GENERAL SPECIFICATIONS (CONT.)

SUCTION LIFT

TEMPERATURE

Ambient and Liquid:

122 ºF (50 ºC) Maximum
14 ºF (-10 ºC) Minimum

5 ft. (2.5 meters) of water column maximum. 11
psia minimum internal pressure (4 psi maximum
vacuum).

PAINT

Powder Coating

3

1.4 PRODUCT CODE

Series G Model G pumps are available in a variety
of different configurations. For a breakdown of the
options included in a specific pump, co mpare the
pump model number and product code found on
the pump nameplate with the model/produ ct code
breakdown shown in Figure 1. A sample name­plate is shown in Figure 2.

Figure 2. Sample Nameplate

4

SECTION 2

WARNING

INSTALLATION

2.1 UNPACKING

Pumps are shipped f.o.b. 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 file 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 SERIES G MODEL 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, FLAM­MABLES, ETC.).

THE PERSONNEL RESPONSIBLE FOR
INSTALLATION, OPERATION AND
MAINTENANCE OF THIS EQUIPMENT
MUST BECOME FULLY ACQUAINTED
WITH THE CONTENTS OF THIS MAN­UAL.

ANY SERVICING OF THIS EQUIPMENT
MUST BE CARRIED OUT WHEN THE
UNIT IS STOPPED AND ALL PRES­SURE HAS BEEN BLED FROM THE LIQ­UID END. SHUT-OFF VALVES IN
SUCTION AND DISCHARGE SIDES OF
THE LIQUID END SHOULD BE CLOSED
WHILE THE UNIT IS BEING SERVICED.
ACTIONS SHOULD BE TAKEN TO ELIM­INATE THE POSSIBILITY OF ACCIDEN­TAL START-UP WHILE SERVICING IS
TAKING PLACE. A NOTICE SHOULD BE
POSTED BY THE POWER SWITCH TO
WARN THAT SERVICING IS BEING
CARRIED OUT ON THE EQUIPMENT.
SWITCH OFF THE POWER SUPPLY AS
SOON AS ANY FAULT IS DETECTED
DURING OPERATION (EXAMPLES:
ABNORMALLY HIGH DRIVE TEMPERA­TURE, UNUSUAL NOISE, DIAPHRAGM
FAILURE).

2.3 STORAGE
Short Term 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.

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 temperatur e 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.

5

The prepared equipment should be co vered 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 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

1. 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 stor­age, drain this material and refill the equipment
with the recommended lubricant for equipment
commissioning.

2. Remove drive motor and liquid end, and brush
all unpainted metal surfaces with multipurpose
grease (NLGI grade 2 or 3). Store these unat­tached.

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 your distributor or LMI/
Milton Roy Service Department for recommended
VPCI materials.

Support the pump firmly in a level position on a
solid, vibration-free foundation, preferably with the
base above floor 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 filling or drain­ing procedures.

Series G Model G pumps are provided with mount­ing holes to accommodate anchor bolts. Refer to
Figure 3 for mounting hole dimensions.

Some Series G Model G pumps are shipped with
motors dismounted. After anchoring pump in posi­tion, install motor, referring to Figure 7, Sheet 1.

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 PIPING
NPSH Considerations

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 flow pi
(3.14) times the average flow. Therefore, piping
must be designed for a flow 3.14 times the pump
capacity; this means that a pump rated for 88 gal­lons per hour (333.1 L/hr.) requires piping sufficient
for 3.14 x 88 gph, or 276 gph (1044.7 L/ hr.).

2.4 MOUNTING

TO AVOID POSSIBLE DAMAGE TO
EITHER PUMP OR PERSONNEL, BOLT
PUMP DOWN AS SOON AS IT IS IN
POSITION.

Figure 3. Mounting Hole Dimensions

6

To minimize viscous flow 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 LMI Distributor to determine the
necessary pipe size.

• Use piping heavy enough to withstand
maximum pressures.

• Remove burrs, sharp edges, and debris
from inside piping. Blow out all pipe lines
before making final connections to pump.

General Piping Considerations

• Use extreme care in piping to plastic liquid
end pumps with rigid pipe such as PVC. If
excessive stresses or vibration is unavoid­able, flexible connections are recom­mended.

• 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.

• Because vapor in the liquid end will cause
inaccurate pump delivery, piping should be
sloped to prevent vapor pockets

• When pumping suspended solids (such as
slurries), install plugged crosses at all 90°
line turns to permit line cleaning without
dismantling piping.

• See Figure 4 for a typical recommended
pump installation scheme.

Figure 4. Typical Recommended Pump Installation Scheme

7

Suction Piping Considerations

• It is preferable to have the suction of the
pump flooded by locating the liquid end
below the lowest level of the liquid in the
supply tank. Installing the supply vessel on
the suction line close to the pump can help
ensure a flooded suction line. (Consult with
your LMI distributor or the LMI/Milton Roy
technical support team for assistance in
such applications.)

• Avoid negative suction pressure conditions
(suction lift), as such conditions adversely
affect metering accuracy. A lift of 8.2 feet
(2.5 meters) of water column is the maxi­mum suction lift permissible.

• If possible use metal or plastic tubing for
the suction line because tubing has a
smooth inner surface and can be formed
into long, sweeping bends to minimize fric­tional flow losses.

• A strainer should be used in the suction
line to prevent foreign particles from enter­ing the liquid end. This and any other mea­sures which prevent debris from entering
and fouling the ball-checks will give
increased maintenance-free service.
Check strainer frequently to prevent block ­age which could lead to cavitation.

• Keep suction piping as short and straight
as possible.

• Series G Model G 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, in these
negative pressure applications it is impor­tant that all connections be absolutely drip
free and vacuum tight, and that a foot
valve be installed at the bottom of the suc­tion line (see Figure 5).

• When pumping a liquid near its boiling
point (max temp is 125 degrees F), provide
enough suction head to prevent the liquid
from “flashing” into vapor when it enters
the pump liquid end on the suction stroke.

• Piping size should be larger than the liquid
end suction fitting to prevent pump s tarva­tion.

• If long suction lines are unavoidable, install
a stand pipe near the pump in the suction
line.

• Suction piping must be absolutely airtight
to ensure accurate pumping. After installa­tion, test suction piping for leaks with air
and soap solution.

Discharge Piping Considerations

• Install pipe large enough 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 rated pressure
(Max. allowable working pressure shown
on the pump nameplate).

• The pump will not deliver a controlled flow
unless the discharge line pressure is 10 psi
greater than the suction line pressure.
There are a number of ways to create an
artificial pressure, such as by installing a
back pressure valve. (Please contact your
LMI distributor for recommendations to
increase back pressure in slurry applica­tions.)

Figure 5. Suction Lift Installation

• When pumping water-treatment chemicals
directly into boiler drums, use one liquid
end assembly for each boiler drum. Dis-

8

charging 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
other outlets.

Back Pressure Valves

A Milton Roy Back Pressure Valve (Figure 4)
should be installed in the discharge line near the
pump to ensure sufficient discharge head pressure
for proper pump metering action. 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).

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 flow 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 flow 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 your LMI distributor for further information on
pulsation dampeners.

Safety Valves

Motor-driven positive displacement pumps can
develop excessive discharge pressures long
before thermal overload devices interrupt the motor
electrical circuit. To prevent a blocked discharge
line from causing damage to the pump, piping, or
process equipment, install a Milton Roy Safety
Valve in the pump discharge line. This valve is
designed and sized to handle system flow 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 pump damage from accidental
valve closure.) Pipe the safety valve outlet back to
the suction tank or to drain, but in either case
ensure that the pipe end is continuously visible so
safety valve leakage may be detected. Milton Roy
safety valves must be installed at top of supply tank
in order to function properly (see Figure 4).

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 flow
through the discharge piping and will isolate the
pump discharge from system pressures (a safety
consideration).

Shut-off Valves

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.

2.6 LEAK DETECTION

The Series G Model G pumps are equipped with a
leak detection port. For ease of installation, each
pump has a plastic tubing connector installed in the
leak detection port (see item 448 in Figure 7, Sheet

2). In the event of a failure of the oil seal (70 in Fig­ure 7, Sheet 1) or PTFE diaphragm assembly (260
in Figures 8 through 13), pump drive oil or process
fluid will escape from this leakage port. During
pump installation, actions should be t aken to i nsure
that this leakage is safely collected by installing
tubing between the leak detection port and an
appropriate containment vessel.

2.7 ELECTRICAL CONNECTIONS

Ensure that the electrical supply matches the pump
motor nameplate characteristics.

OPERATION WITH THE WRONG
MOTOR ROTATION WILL DAMAGE THE
PUMP AND MOTOR AND VOID THE
WARRANTY.

9

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.

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.

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SECTION 3

WARNING

OPERATION

3.1 INITIAL START-UP

FAILURE TO CHECK TORQUE ON NON­METALLIC HEAD BOLTS PRIOR TO
STARTUP AND AFTER ONE WEEK OF
OPERATION MAY EXPOSE
OPERATING PERSONNEL TO
HAZARDOUS LIQUIDS.

Check the torque on all non-metallic head bolts
prior to startup. Recheck torque on all non-metallic
head bolts after pump has been operating for one
week. Torque the head assembly screws in a
crosswise pattern as follows:

(1) Liquid End Size SG5 and SG6 non-metallic

head bolts to 90 inch pounds.

(2) Liquid End Size SG7 non-metallic head

bolts to 125 inch pounds.
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 oil

fill cap and fill the pump casing until level is
between the markings on the oil fill cap dipstick,
(approximately 3 quarts (2.8 Liters)).

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.NOTE:

ABOVE 50°F

Chevron
Exxon
Mobil
Texaco
Shell

................. N.L. Gear Compound 220

.................... Spartan E.P. 220

...................... Mobilgear 630

................ ... Meropa 220

...................... Omaha 220

BELOW 50°F

Chevron

................. N.L. Gear Compound 68

Exxon

.....................Spartan E.P. 68

......... ... ... ... ... .Mobilgear 626

Mobil
Texaco
Shell

.................. .Meropa 68

...................... .Omaha 68

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.

DO NOT TRY TO ADJUST PUMP
CAPACITY BELOW O% OR ABOVE
100% OR DAMAGE TO PUMP MAY
OCCUR. KEEP ADJUSTMENT KNOB
BETWEEN 0 AND 100 %.

Manual Capacity Control

To adjust pump capacity, loosen the stroke locking
knob (320, Figure 7, Sheet 2) located in the pump­side cover. Pump capacity is adjusted by turning
the micrometer type stroke adjustment knob (330)
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.

Filling Pumping System

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 fill the entire pumping system with liq­uid before starting pressure tests. A simple method
to assure priming of the pump is to install a tee an d
a shut-off valve at the discharge connection of the
pump.

11