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

Series G Model D

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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: ________________________________

339-0080-000

ISSUED JULY 2011

Precautions Amendment to Pump Manual

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

!

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. He

!

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. A

!

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.

Indicating Device:

ad Loss / Over Pressure Protection / Back Pressure-Anti-Siphon Valve:

dditional Operation and Installation Instructions for 316SS or PVC Liquid Ends:

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.

PLACE THIS AMENDMENT TO THE MACROY SD MANUAL (339-0080-000) BEHIND
THE COVER SHEET (APRIL 2008)

TABLE OF CONTENTS

SECTION DESCRIPTION PAGE

Series G Model D Pump Model Number and Options ................................................................................ iii

1.0 DESCRIPTION

1.1 General Information ........................................................................................................................... 1

1.2 Principles of Operation ...................................................................................................................... 2

1.3 General Specifications ...................................................................................................................... 3

2.0 INSTALLATION

2.1 Unpacking ........................................................................................................................................... 5

2.2 Storage ................................................................................................................................................ 5

2.3 Safety Precautions ............................................................................................................................. 5

2.4 Mounting ............................................................................................................................................. 6

2.5 Drip Collection .................................................................................................................................... 6

2.6 Installation .......................................................................................................................................... 6

2.6.1 NPSH Considerations ............................................................................................................... 8

2.6.2 General Piping Considerations ............................................................................................... 8

2.6.3 Suction Piping Considerations ................................................................................................ 8

2.6.4 Discharge Piping Considerations ............................................................................................ 9

2.7 Valves .................................................................................................................................................. 9

............................................................................................................................................

...........................................................................................................................................

1

5

2.8 Electrical Connections ..................................................................................................................... 10

3.0 OPERATION

3.1 Start-Up Procedures and Checks .................................................................................................... 11

3.2 Checking the Electrical Connection of the Motor .......................................................................... 11

3.3 Start-Up .............................................................................................................................................. 11

3.4 Capacity Calibration ........................................................................................................................ 11

4.0 MAINTENANCE

4.1 Preventative Maintenance............................................................................................................... 13

4.2 Returning Pumps to the Factory for Repair ................................................................................... 13

4.3 Routine Maintenance ....................................................................................................................... 13

4.4 Spare Parts ....................................................................................................................................... 14

4.4.1 Size SD2 and SD4 Liquid Ends - PVC, PVDF, Polymer, and H2SO4.................................... 14

4.4.2 Size SD4 Liquid Ends - PVC, PVDF, Polymer, H2SO4, and Slurry ...................................... 15

4.4.3 Size SD2 and SD4 Liquid Ends - Stainless Steel ................................................................. 15

4.4.4 Size SD7 and SD8 - Liquid Ends - PVC, PVDF, H2SO4, Polymer, and Slurry ...................... 15

.............................................................................................................................................

.........................................................................................................................................

11

13

4.4.5 Size SD7 and SD8 - Liquid Ends - Stainless Steel .............................................................. 16

i

SECTION DESCRIPTION PAGE

4.5 Corrective Maintenance ................................................................................................................... 16

4.5.1 Check Valve Assemblies Replacement: Liquid Ends SD2 and SD4 - PVC, PVDF, and

H2SO4........................................................................................................................................ 16

4.5.2 Check Valve Replacement: Liquid End Sizes SD2 and SD4 - Polymer ............................. 17

4.5.3 Check Valve Replacement: Liquid End Sizes SD2 and SD4 - Metallic .............................. 17

4.5.4 Check Valve Replacement: Liquid End Sizes SD4 - Slurry ................................................. 18

4.5.5 Replacement of Ball, Seat, and Seal: Liquid End SD7 and SD8 - PVC and PVDF ........... 18

4.5.6 Check Valve Replacement: Liquid End Size SD7 and SD8 - Polymer .............................. 19

4.5.7 Check Valve Replacement: Liquid End Size SD7 and SD8 - Slurry.................................. 19

4.5.8 Check Valve Replacement: Liquid End Size SD7 and SD8 - Stainless Steel .................. 19

4.6 Diaphragm and Oil Seal Bellows Replacement ........................................................................... 20

4.6.1 Diaphragm Replacement: Liquid End Size SD2 ................................................................. 20

4.6.2 Diaphragm Replacement: Liquid End Size SD4, SD7, and SD8 ....................................... 20

4.7 Oil Seal Bellows Replacement ....................................................................................................... 21

4.8 Restarting the Pump ........................................................................................................................ 22

5.0 PARTS LIST ............................................................................................................................................. 23

5.1 Parts List for Drive ............................................................................................................................ 25

5.2 Parts List for D2 Plastic Liquid End PVC, PVDF, H2SO4, and Polymer-NPT / PVC,

PVDF - Tubing ................................................................................................................................... 27

5.3 Parts List for SD2 Metallic Liquid End Stainless Steel-NPT .......................................................... 28

5.4 Parts List for SD4 Metallic Liquid End Stainless Steel-NPT .......................................................... 29

5.5 Parts List for SD4 Plastic Liquid End PVC, PVDF, H2SO4, Slurry, and Polymer-NPT / PVC,

PVDF, and H2SO4 - Tubing ................................................................................................................ 31

5.6 Parts List for SD7 and SD8 Plastic Liquid End PVC-NPT / Tubing, PVDF-NPT, Polymer-NPT,

Slurry-NPT, & H2SO4-NPT .................................................................................................................. 35

5.7 Parts List for SD7 and SD8 316SS-NPT Liquid End ........................................................................ 38

6.0 TROUBLESHOOTING

...............................................................................................................................

39

Change Bars

The areas in this manual which are different from previous editions are marked with change bars (as
shown to the right of this paragraph) to indicate the addition of new or revised information.

ii

MACROY D PUMP MODEL NUMBER AND OPTIONS

Frame and Liquid End

Frame and Liquid End (D Frame)

Code

SD2

SD4

SD7

SD8

Description

Max 0.7 GPH / 175 PSI

Max 14.4 GPH

Max 50 GPH

Max 127 GPH

Stroking Speed

Code Description

1 43 SPM

2 86 SPM

6 120 SPM

3 173 SPM

Motor

Code Description

X NEMA 56C Flange Less Motor

8 115/230 VAC, 60 Hz,1 PH, 1800 RPM

9 115/230 VAC, 50 Hz,1 PH, 1500 RPM

J 230/460 VAC, 60 Hz, 3 PH, 1800 RPM

L 220/380 VAC, 50 Hz, 3 PH, 1500 RPM

P DC Variable Speed Drive

Stroking Speed

Motor

Liquid End Material

Code Description

2 PVDF

7 316ss

8 PVC

P Polymer Service

L Slurry Applications

NH

Connections

Code Description

P NPT

T Tubing

B Outgassing Liquid Applications (NPT)

C Outgassing Liquid Applications (Tubing)

Liquid End Material

Connections

Applications

2SO4

iii

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iv

SECTION 1

DESCRIPTION

1.1 GENERAL INFORMATION

The Series G Model D is a reciprocating, chemical dos­ing pump capable of producing flows up to 115 gallons
per hour (430 liters per hour) at pressures up to 175 psi
(12 Bar). 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. It is
designed for industrial service and offers an accuracy of
±2% of full rated flow between 10% and 100% of its flow
range.

Figure 1:
Pump Assembly

1

The basic pump components as illustrated in Figure 1
are:

• a drive device comprising a motor (1)

• a mechanical assembly (2)

• a liquid end (3).

An elastomeric bellows provides a leak-tight seal be­tween the mechanical assembly and the liquid end.

Capacity adjustment is manually controlled by a stroke
adjustment knob (4).

7

2

8

3

4

6

5

1
2
3
4

Motor
Mechanical Assembly
Liquid End
Stroke Adjustment Knob

5
6
7
8

Liquid End Mounting Assembly
Check Valve Assembly (Suction)
Check Valve Assembly (Discharge)
Stroke Lock Knob

1

Figure 2:
Stroke Control Operating
Principle

1

2

(A) (B)

3

4

5

(A)

7

(B)

Suction Phase

Setting to Maxmum Stroke

1
2
3
4

Worm
Worm Gear
Eccentric
Connecting Rod

5
6
7
8

1.2 PRINCIPLES OF OPERATION

Drive Assembly (See Figure 2)

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 end size and stroke length.
Stroke length can be increased while the pump is run­ning by counterclockwise turning of the stroke adjust­ment knob. The drive assembly works on the principle
of a variable eccentric. The rotational motion of the motor
is transmitted by the worm (1) to the worm gear (2)
which is linked to an eccentric system (3). The eccen­tric system then converts the rotary gear motion into
linear reciprocating motion of the connecting rod (4). At
0% capacity setting, the connecting rod axis (B) is
aligned with the gear axis (A) and no movement of the
connecting rod takes place. At 100% capacity setting,
an eccentricity exists between the connecting rod axis
(B) and the gear axis (A) which results in linear move­ment of the connecting rod and resulting pumpage.

Drive parts (See Fig. 8 for limited drive parts available)
are no longer sold by Milton Roy. When drive parts are
found to be bad a complete new painted pump body
with all gears, stroke controls, etc. can be purchased
from Milton Roy. The customer will only need to mount
the liquid end/motor from the existing pump.

Zero Stroke Setting

(A)

(B)

Discharge Phase

6

8

Diaphragm
Stroke: two times the distance between (A) and (B)
Position at rear neutral point
Position at forward neutral point

Mechanically Actuated Diaphragm Liquid End
(See Figure 2)

The diaphragm assembly (5) is mechanically linked to
the connecting rod (4) and has the same reciprocating
motion. As the diaphragm starts back on the suction
stroke, the pressure immediately drops inside the liq­uid end. When the pressure in the liquid end 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 (diaphragm head).
When the suction stroke ends, the diaphragm move­ment momentarily stops and the pressure in the liquid
end equalizes with the pressure in the suction line caus­ing the suction ball check to reseat.

NOTE: It is important that the pressure 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 which will have a nega­tive impact on the performance of the pump.
If you suspect the possibility of cavitation, con­tact your dealer for assistance.

2

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 reseats. The cycle
then starts again.

PAINT:

Power Coating

SUCTION LIFT:

6.6 Ft (2 meters) of water column maximum

11.5 psia minimum internal pressure (3.2 psi maximum
vacuum)

1.3 GENERAL SPECIFICATIONS

FLOW RATE:

Up to 115 GPH (430 L/H)

PRESSURE:

Up to 175 PSIG (12 BAR)

LIQUID END TYPE:

Mechanically Actuated Diaphragm

DRIVE TYPE:

Variable Eccentric

STEADY STATE ACCURACY:

±2% of pump full rated capacity between 10% and 100%
of rated capacity.

WEIGHT:

38 lb (17.2 kg)

CAPACITY ADJUSTMENT:

Lockable stroke adjustment knob is adjustable from 0%
to 100% while pump is running.

LUBRICATION:

Drive is lubricated in an oil bath (Mobil SHC 629, 1 Quart).

TEMPERATURE:

Ambient and Liquid:

122 0F (50 0C) Maximum

14 0F (-10 0C) Minimum

3

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4

SECTION 2

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 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 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 greatest extent possible.

When the instructions given in this section are com­pleted, the equipment is to be stored in a shelter; 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 inches or more above the ground.

If equipment is to be shipped directly from the factory
into long term storage, contact the factory to arrange for
factory preparation.

Pump Drive

1. Remove motor and flood the gearbox compartment
(Item 2 in Figure 1) 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. 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.

2.3 SAFETY PRECAUTIONS

WHEN INSTALLING, OPERATING, AND
MAINTAINING THIS SERIES 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 TAK-

5

Figure 3:
Series G Model D
Dimensional Outline

ING 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).

2.4 MOUNTING

Support the pump firmly in a level position on a solid,
vibration-free foundation. The pump should preferably
be positioned 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 and pump adjustments.

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

Pumps installed outdoors should be protected by a shel­ter.

2.5 DRIP COLLECTION

In the event of a failure of the diaphragm or oil seal bel­lows, provisions need to be made to contain the pro­cess fluid or pump oil. This is particularly important
when handling fluids which may be harmful to plant per­sonnel.

To collect fluid in the event of a diaphragm or oil seal
rupture, (See Figure 1) position a tray under the plain
hole located at the bottom of the liquid end mounting
assembly (5). For SD7 or SD8 pumps, position tray
under tube fitting located at bottom of liquid end mount­ing assembly. Alternatively, a tube may be installed
onto this tube fitting to drain any leakage to a suitable
container.

2.6 INSTALLATION

Figure 4 displays typical installations (both correct and
incorrect). Figure 5 illustrates the recommended piping
and accessories in a metering pump installation.

As illustrated in the upper right portion of Figure 4, there
must be no swan-necks or stagnant volumes in the suc­tion line. In this illustration, the loop at the top of the
tank forms an air trap. Eventually, air or gases will bubble
out of solution and accumulate in the trap leading to a
loss of prime condition.

6

Figure 4:
Typical Installation

4

6

5

3

4

6

1

5

1

3

2

4

6

1

9

3

5

7

1
2
3
4
5

Tank
Foot Valve (with Filter)
Metering Pump
Process Piping
Bleed Valve

8

6
7
8
9

-

Injection Nozzle
Shut-off Valve
Filter
Pulsation Damper

-

7

Figure 5:
General Piping

2.6.1 NPSH CONSIDERATIONS

Size piping to accommodate peak instantaneous flow.
Because of the reciprocating motion of the pump dia­phragm, peak instantaneous flow is approximately equal
to 5 times the average flow. For example, a pump rated
for 16 gallons per hour (61 L/hr.) requires piping suffi­cient for 5 x 16 gph, or 80 gph (303 L/hr.).

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 dealer to deter­mine the necessary pipe size.

2.6.2 GENERAL PIPING CONSIDERATIONS

Use extreme care in piping to plastic liquid end pumps
with rigid pipe such as PVC. If excessive pipe stress 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.

Use piping heavy enough to withstand maximum pres­sures. Remove burrs, sharp edges, and debris from
inside piping. Blow out all pipelines before making final
connections to pump.

Because vapor in the liquid end will cause inaccurate
pump delivery, piping should be sloped up from pump
suction check to the supply tank to prevent formation of
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 5 for a typical recommended pump installa­tion scheme.

2.6.3 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.

To minimize the chances of a loss-of-prime condition,
the pump should be installed as close as possible to
the supply vessel.

Avoid negative suction pressure conditions (suction lift),
as such conditions adversely affect metering accuracy.
A lift of 6.6 feet (2 meters) of water column is the maxi­mum permissible suction lift.

Series 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 (suction lift), in these nega-

8

tive 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 upper left illustration of Figure 4).

When pumping a liquid near its boiling point, provide
enough suction head to prevent the liquid from “flash­ing” into vapor when it enters the pump liquid end on the
suction stroke.

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 liquid end check valves will give increased
maintenance-free service. Check strainer frequently to
prevent blockage which could lead to cavitation. Keep
suction piping as short and straight as possible.

Piping size should be larger than the liquid end suction
fitting to prevent pump starvation.

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.

2.6.4 DISCHARGE PIPING CONSIDERATIONS

2.7 VALVES

Back Pressure Valves

All metering pumps are prone to overpumping (exces­sive output) at low discharge pressures. To prevent this
condition from occurring, it is necessary to maintain
approximately 10 psi (0.7 bar) back pressure against
the pump. This can be accomplished through the in­stallation of a back pressure valve in the discharge line.
Typically, 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).

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 close 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 dealer for
further information on pulsation dampeners.

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 (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. One way to create an artificial pres­sure is the installation of a back pressure valve. (Please
contact your dealer for recommendations to increase
back pressure in slurry applications).

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 other outlets.

Safety Valves and Priming 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
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.

To aid in pump start-up, it is advisable to install a prim­ing valve on the discharge side of the liquid end.

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 5 shows recommended valve locations.

9