Milton Roy GB Series User manual

Series G Model “B” Pump
Instruction Manual
GB.MR.ENG.339-0049-000.04/2020

TABLE OF CONTENTS
SECTION 1 DESCRIPTION ……………………………………………………………………………………… 1
GENERAL ……………………………………………………………………………………………………………… 1
PRINCIPLES OF OPERATION ……………………………………………………………………………………… 1
GENERAL SPECFICATIONS ………………………………………………………………………………………… 1
PRODUCT CODE ……………………………………………………………………………………………………… 2
SECTION 2 INSTALLATION …………………………………………………………………………………… 3
UNPACKING …………………………………………………………………………………………………………… 3
SAFETY PRECAUTIONS …………………………………………………………………………………………… 3
STORAGE ……………………………………………………………………………………………………………… 3
HANDLING OF PUMP ………………………………………………………………………………………………… 3
MOUNTING …………………………………………………………………………………………………………… 4
PIPING ………………………………………………………………………………………………………………… 4
LEAK DETECTION …………………………………………………………………………………………………… 7
ELECTRICAL CONNECTION ………………………………………………………………………………………… 8
SECTION 3 OPERATION ………………………………………………………………………………………… 9
INITIAL START-UP …………………………………………………………………………………………………… 9
SECTION 4 MAINTENANCE …………………………………………………………………………………… 11
SPARE PARTS ……………………………………………………………………………………………………… 11
SHIPPING PUMPS FOR REPAIR ………………………………………………………………………………… 11
PREVENTATIVE MAINTENANCE ………………………………………………………………………………… 11
CORRECTIVE MAINTENANCE …………………………………………………………………………………… 12
SECTION 5 TROUBLESHOOTING GUIDE ………………………………………………………………… 19
SYMPTOMS & REMEDIES ………………………………………………………………………………………… 19
SECTION 6 PARTS ……………………………………………………………………………………………… 21
PARTS LIST FOR GB DRIVE ASSEMBLY ………………………………………………………………………… 23
PARTS LIST FOR GB DRIVE ASSEMBLY - CONTINUED ……………………………………………………… 24
PARTS LIST FOR GB0080~GB0450 LIQUID END ……………………………………………………………… 29
PARTS LIST FOR GB0500~GB1200 LIQUID END ……………………………………………………………… 30
PARTS LIST FOR GB1500 LIQUID END ………………………………………………………………………… 32
PARTS LIST FOR GB1800 LIQUID END ………………………………………………………………………… 33
PARTS LIST FOR GB DOUBLE DIAPHRAGM LIQUID END WITH SWITCH AND GAUGE ………………… 38
i

Figure 1-1. Sample Nameplate …………………………………………………………………………………… 2
Figure 2-1. Handling a Series GB Pump ………………………………………………………………………… 4
Figure 2-2. Mounting Hole Dimensions …………………………………………………………………………… 4
Figure 2-3. Typical Recommended Pump Installation Schematic ……………………………………………… 5
Figure 2-4. Suction Lift Installation ………………………………………………………………………………… 6
Figure 2-5. Terminal Connection for Three-phase Motor ……………………………………………………… 8
Figure 6-1. Series GB Basic Parts - Side View ………………………………………………………………… 21
Figure 6-2. Series GB Basic Parts - Top View ………………………………………………………………… 22
Figure 6-3. GB0080~GB0450 Plastic Check Valve Parts ……………………………………………………… 25
Figure 6-4. GB0080~GB0450 High Viscosity Check Valve Parts …………………………………………… 25
Figure 6-5. GB0500~GB0600 Plastic Check Valve Parts ……………………………………………………… 25
Figure 6-6. GB0500~GB0600 High Viscosity Check Valve Parts …………………………………………… 25
Figure 6-7. GB0700~GB1200 Plastic Check Valve Parts ……………………………………………………… 26
Figure 6-8. GB0700~GB1200 High Viscosity Check Valve Parts …………………………………………… 26
Figure 6-9. GB1500 Plastic Check Valve Parts ………………………………………………………………… 26
Figure 6-10. GB1500 High Viscosity Check Valve Parts ……………………………………………………… 26
Figure 6-11. GB1800 Plastic Check Valve Parts ………………………………………………………………… 27
Figure 6-12. GB0080~GB0450 Stainless steel liquid End ……………………………………………………… 28
Figure 6-13. GB0500~GB0600 Stainless steel liquid End ……………………………………………………… 30
Figure 6-14. GB0700~GB1200 Stainless Liquid End …………………………………………………………… 31
Figure 6-15. GB1500 316SS Liquid End ………………………………………………………………………… 34
Figure 6-16. GB1800 316SS Liquid End ………………………………………………………………………… 36
Figure 6-17. Double Diaphragm (Standard, All Liquid End Sizes) …………………………………………… 38
Figure 6-18. Leak Detection, Switch and Gauge (Standard, All Liquid End Sizes) ………………………… 39
LIST OF ILLUSTRATIONS
ii

GENERAL
The Series G Model " B " pumps are reciprocating, chemical dosing pumps capable of producing
controlled flows up to 1800 liters per hour at pressures up to 10 BAR (depending on the model). These
pumps feature a mechanically actuated diaphragm, which eliminates the need for 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 ±1.5% of 100% rated flow between 10% and 100% of its flow range.
PRINCIPLE 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 end 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 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,
negatively impacting the performance of the pump. If you suspect the possibility of cavitation, contact
your Milton Roy Representative 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.
GENERAL SPECIFICATIONS
Flow Rate
Up to 1800 L/H
Pressure
Up to 10 BAR
Design
Mechanically Actuated Diaphragm
Drive
Variable Eccentric
SECTION 1
DESCRIPTION
1

Accuracy
±1.5% 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
Temperature
Ambient and Liquid: 50℃Maximum
-10 ℃Minimum (Metal Liquid End)
10 ℃Minimum (Plastic Liquid End)
Suction Lift
2.5 meters of water column maximum.
PRODUCT CODE
Series G pumps are available in a variety of different configurations. For a breakdown of the options
included in a specific pump, compare the pump model number and product code found on the pump
nameplate with the model/product code breakdown. A sample nameplate is shown in Figure 1-1.
Model Code :
Order No :
Serial No :
Operating Flow : L/H
Operating Press : Bar
WWW.MILTONROY.COM
FigureFigure 11--11. Sample Nameplate. Sample Nameplate
2

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.
SAFETY PRECAUTIONS
When installing, operating, and maintaining the 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.).
STORAGE
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.
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 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.
SECTION 2
INSTALLATION
3

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.
HANDLING OF PUMP
To avoid damaging the pump while moving or installing a Series G pump, follow the instructions below.
Refer to Figure 2-1
1. Place a sling under the motor flange.
2. Cross the two ends of the sling and close the loop.
3. Place the other end of the sling under the liquid end mounting flange.
4. Make sure the entire unit is well balanced before attempting to move the pump.
CAUTION:
To avoid possible damage to either pump or personnel, bolt pump down as soon as it is in position.
MOUNTING
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 pumps are provided with mounting holes to accommodate anchor bolts. Refer to figure 2-2 for
mounting hole dimensions.
Some Series G pumps are shipped with motors dismounted. After anchoring pump in position, install
motor, referring to Figure 6-1. Make sure spring (Make sure spring (360360) provided with pump is installed in worm shaft prior to) provided with pump is installed in worm shaft prior to
motor installation.motor installation.
Pumps installed outdoors should be protected by a shelter.
FigureFigure 22--11. Handling a Series GB Pump. Handling a Series GB Pump
FigureFigure 22--22. Mounting Hole Dimensions. Mounting Hole Dimensions
4

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 100 liters per hour requires piping sufficient for 3.14×100 L/hr (314 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 nearest
Milton Roy representative to determine the necessary pipe size.
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.
●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.
●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 iline turns to permit
line cleaning without dismantling piping.
●See Figure 2-3 for a typical recommended pump installation scheme.
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
FigureFigure 22--33..
5

ensure a flooded suction line. (Consult Milton Roy for assistance in such applications.).
●Avoid negative suction pressure conditions (suction lift), as such conditions adversely affect metering
accuracy. A lift of 2.5 meters of water column is the maximum suction lift permissible.
●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, 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 2-4 ).
●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 ball-checks 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.
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 Milton Roy 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.
FigureFigure 22--44. Suction Lift Installation. Suction Lift Installation
6

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).
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 Milton Roy Company 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 2-3).
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 2-3 shows recommended valve locations.
LEAK DETECTION
Without switch or gauge
Series G Model B 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 6-2). In the event of a
failure of the oil seal (70 in Figure 6-1) or diaphragm assembly (see item 261 in Figure 6-2）,pump drive oil or
process fluid will escape from this leakage port. During pump installation, actions should be taken to insure
that this leakage is safety collected by installing tubing between the leak detection port and an appropriate
containment vessel.
7

With switch and gauge
Series G Model B pump also is available with an option that includes tubing to a pressure gauge and
switch as shown in figure 6-18 In the event of a diaphragm leak the process fluid is trapped inside the
system and pressure switch (760) is tripped to set an alarm or shutdown.
This leak detection system is not filled with any fluid and will only be pressurized in the event of a seal
failure. A drain (790) is provided for pressure relief prior to system disassembly.
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.
CAUTION:
Operation with the wrong motor rotation will damage the pump and motor and void the warranty.
CAUTION:
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.
FigureFigure 22--55..
8

SECTION 3
OPERATION
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 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 )).
Recommendation oil:
CAUTION:
Pump is required to stop running if the surround temperature is below -10℃.
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.
Manual Capacity Control
To adjust pump capacity, loosen the stroke locking screw located in the pump side cover. Pump capacity
is 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.
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 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 exhaust when starting the pump.
Surround Temp.
> - 5℃
MOBILGEAR 600 XP 460
Great Wall L-CKD460
Model
GB1200
GB1500 and GB1800
Note: Equivalent oil of other brand is allowed.
Surround Temp.
> - 5℃
MOBILGEAR 600 XP 220
Great Wall L-CKD220
Surround Temp.
-10℃to - 5℃
MOBILGEAR 600 XP 68
Model
9

Capacity Calibration
After the first 12 hours of operation, the pump may be tested and calibrated to find the exact pump
capacity under specific operating conditions.
Usually, calibrating the pump at only 100, 50, and 10 percent capacity settings is enough to indicate pump
performance 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. It
may be necessary to create discharge head at the liquid take off point so that the pump will operate properly.
(See Section 2 for recommended ways to do this.).
CAUTION:
This method is not generally recommended as it may expose operating personnel to hazardous liquids.
Furthermore, the pump may over pump dramatically and the position of the capacity adjustment knob
may have little effect on measuring flow rate.
10

SECTUION 4
MAINTENANCE
SPARE PARTS
The following spare parts should be stocked for each pump to prevent serious delays in repairs. Refer to
Figures 6-1~ 6-18 and to the accompanying parts lists.
Parts orders must include the following:
1. Quantity required
2. Part number
3. Part description
4. Pump serial number (found on nameplate)
5. Pump model number (found on nameplate)
6. Pump product code (found on nameplate)
Always include the serial number, model number, and product code in all correspondence regarding the unit.
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 flushed from the pump liquid end and
oil should be drained from the pump housing before the pump is shipped.
NOTE:
A completed Material Safety Data Sheet (MSDS) 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 Materials
Safety Data Sheet must accompany all returns.
All inquiries or parts orders should be addressed to your local Milton Roy representative or distributor.
PREVENTIVE MAINTENANCE
Milton Roy pumps are carefully designed, manufactured, assembled, and quality tested to give reliable
service with minimal maintenance. However, a weekly maintenance check is recommended to visually
confirm proper operation of the pump.
Drive
Initially, change gear drive oil after the first 250 hours of operation. Then change drive oil after every 4000
hours of operation or every six months, whichever comes first.
Diaphragm Assembly
The Series G diaphragm assembly should be replaced every 4000 hours of operation to avoid the
possibility of failure. Refer to the instructions in the "Corrective Maintenance "section.
Oil Seal
The Series G oil seal should be replaced every 4000 hours of operation to avoid the possibility of failure.
Oil seal replacement requires the removal of the diaphragm assembly, so it is recommended that the oil seal
and diaphragm assembly be replaced at the same time. Refer to the instructions in the "Corrective
Maintenance "section.
11

Check Valves
Milton Roy Company recommends that check valve balls, seats, gaskets, and o-rings be replaced on a
annual basis. If highly corrosive material (acids, slurries, etc.) is being pumped, some applications may
require more frequent replacement.
To determine if check valves need maintenance, disassemble the check valves following the instructions in the
"Corrective Maintenance" section. Inspect the ball check and seat for chemical or physical damage. The ball
should be perfectly round and free of pits, mars, or scratches. The seat should retain a sharp edge where the ball
contacts for proper sealing. If the seat edge is worn or damaged, or has any pits, mars, 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.
Complete instructions for replacing worn check valve parts are given in the "Corrective Maintenance"
section.
CORRECTIVE MAINTENANCE
CAUTION:
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 pressure before proceeding with dismantling.
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 flushing with water.
Check Valve Replacement
General
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; the ball must be placed
on the sharp edge of the seats.
Check valves are supplied in two different configurations: plastic and stainless steel. Be sure to refer to
the appropriate instructional set below.
CAUTION:
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).
GBGB00800080~GB~GB15001500 Liquid End Plastic Check Valves: DisassemblyLiquid End Plastic Check Valves: Disassembly
Refer to Figure 6-3 ~ 6-10
1. Unscrew the union nut (435). The union end (445) is held in place by the union nut and will separate
12

easily from the other liquid end parts.
2. Unscrew the ball guide (424) from the liquid end.
3. Screw the union nut part way (one or two turns) onto the end of the ball guide that has the seat in it. Be sure
the union nut is on loosely. This will allow a gap for the seat (420) to fall into as it is removed from the ball guide.
4. Set the ball guide/union nut onto a flat surface with the union nut down. Looking into the top of the ball
guide, you will see four large holes surrounding one small hole. Insert a thin, blunt instrument such as a hex
head screwdriver into the small center hole until it rests on the top of the ball (422).
5. Tap screwdriver gently with a hammer until the ball and seat are released from the ball guide.
CAUTION:
If you are disassembling unit for inspection only, be sure to use a blunt instrument and tap gently to
avoid damaging the ball. If the ball and/or seat are damaged during disassembly they will have to be
replaced. If available, to avoid damage, it is advisable to use gentle air pressure (applied at end
opposite the seat - 420) for ball and seat removal.
6. Carefully remove the two or three o-rings (depending on liquid end style) from the ball guide and seat.
7. Carefully clean any parts to be reused. If any chemicals are used in the cleaning process, ensure that
they are compatible with the process liquid.
GBGB00800080~GB~GB15001500 Liquid End Plastic Check Valves: ReassemblyLiquid End Plastic Check Valves: Reassembly
Refer to Figure 6-3 ~ 6-10
1. Fit new o-rings into position on the ball guide and seat.
NOTE:
To assure a tight, leak free seal, new o-rings should be used each time the check valves are disassembled.
2. Drop the ball into the curved inner chamber end of the ball guide.
3. Sit the ball guide on a flat surface so that the side with the ball faces upwards. Position seat on the ball
guide, trapping the ball inside. When the seat is pressed into the ball guide, the beveled edge of the seat
must be facing outward. The bevel should not face the inside of the check valve (refer to Figure 6-3 ~ 6-10).
Use a flat surface such as a board to press the seat into the ball guide with firm, even pressure.
CAUTION:
If the seat is improperly positioned, the ball will not create a tight seal and poor pumping performance will result.
4. Position the union end (445) onto the correct end of the ball guide. Refer to Figure 6-3 ~ 6-10 as the
correct end is determined by whether the valve is intended for the suction or discharge port of the liquid end.
Slip the union nut (435) over the union end and screw tightly (hand tight only) onto the ball guide.
CAUTION:
The order of Assembly of the suction and discharge check valves is different. Refer to Figure 6-3 ~ 6-10
for proper Assembly order. 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).
13

5. Screw the valve Assembly into the liquid end body (hand tight only). DO NOT OVER TIGHTEN.DO NOT OVER TIGHTEN.
GBGB00800080~GB~GB04500450 Liquid End Stainless Steel Check Valves: DisassemblyLiquid End Stainless Steel Check Valves: Disassembly
Refer to Figure 6-12
GB0080~GB0450 stainless steel check valves differ from the plastic versions in that the ball seat is
integral to the ball guide. The seats can not easily be inspected for damage or wear. If you suspect that the
check valve may be damaged or worn, replace the entire check valve assembly as per the instructions
below.
1. Unscrew the coupling (445)
2. Unscrew the ball guide (424) from the liquid end.
3. Remove and discard the o-rings (419).
4. Carefully clean any parts to be reused. If any chemicals are used in the cleaning process, ensure that
they are compatible with the process liquid.
GBGB00800080~GB~GB04500450 Liquid End Stainless Steel Check Valves: ReassemblyLiquid End Stainless Steel Check Valves: Reassembly
1. Screw the correct end of the check valve assembly into the liquid end (refer to Figure 6-12), trapping a
new o-ring between the liquid end and the check valve assembly.
NOTE:
To assure a tight, leak free seal, new o-rings should be used each time the check valves are disassembled.
CAUTION:
The order of assembly of the suction and discharge check valves is different. Refer to Figure 6-4 for
proper assembly order. 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).
2. Screw the coupling (445) onto the check valve assembly, trapping a new o-ring (419, 423) between the
coupling and the check valve assembly.
GBGB05000500~GB~GB15001500 Liquid End Stainless Steel Check Valves: DisassemblyLiquid End Stainless Steel Check Valves: Disassembly
Refer to Figure 6-13 ~ 6-15
1. Unscrew the three screws (441 & 442) and remove them and their three washers (439).
2. Remove the connection(445)(applied to GB1500)or valve clamp (437)(applied to GB0500~GB1200).
3. The connection (435) (applied to GB0500~GB1200), seat (420), ball (422) and ball guide (424) should all
now slip apart easily.
4. Remove and discard the three gaskets (419).
5. Carefully clean any parts to be reused. If any chemicals are used in the cleaning process, ensure that
they are compatible with the process liquid.
NOTE:
Two different type of screws are applied in GB0500~GB1200 Liquid end check valves, and the screw
coded 441 are shorter. Only one type used in GB1500 Liquid end check valves
14

GBGB05000500~GB~GB15001500 Liquid End Stainless Steel Check Valves: ReassemblyLiquid End Stainless Steel Check Valves: Reassembly
Refer to Figure 6-13 ~6-15
1. Drop the ball into the curved inner chamber end of the ball guide.
2. Place a new gasket on the rim of the ball guide, and sit the seat on top of the ball guide, trapping the ball
and gasket between the seat and ball guide.
CAUTION:
Do not reuse old gaskets (419). Even if ball and seat are not worn and do not need replacing, new
gaskets must be used any time the check valves are disassembled.
3. Position the connection (435) onto the correct end of the ball guide with a gasket trapped between the two
metal surfaces. Refer to Figure 6-13 ~ 6-15 as the correct end is determined by whether the valve is
intended for the suction or discharge port of the liquid end.
CAUTION:
The order of assembly of the suction and discharge check valves is different. Refer to Figure 6-13~6-15
for proper assembly order. 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).
4. Position the check valve assembly onto the liquid end, trapping a gasket between the two metal surfaces.
(Seat and pump head).
5. Slide the valve clamp (437) over the connection (435) and screw into the liquid end using the three
screws (441, 442) and their split washers (439).Since one screw (441) is shorter than the others, be sure
that it is screwed into the appropriate hole.
GBGB18001800 Liquid End Plastic Check ValvesLiquid End Plastic Check Valves：：DisassemblyDisassembly
Refer to Figure 6-11
1. Unscrew nut (435)
2. Remove the connection(445)
3. Tight the connection nut(445) with the disassembled flexible tie-in on one side, Don't screw down and
keep some clearance so that the valve seat(421), valve sheath(426), limited position plate(421) and valve
flat(420) and the spring(422) can come off from the valve body.
Note:
The processes of assembly of suction check valve and discharge check valve are different.
4. Put the check valve body and flexible connection nuts on a work table with the nuts pointing down. With a
blunt tool like hex head screwdriver on top of the limited position plate(point to the suction check valve) or on
top of the valve body ( point to discharge check valve).
5. Using a hammer to knock the screwdriver gently until the parts inside the valve body separate from the
valve body.
6. Take out all the o-rings(419) from valve body, valve sheath and limited position plate.
7. Be careful to clean all the parts that will be reused. If chemical reagent is used during cleaning process
15

please make sure the reagent and the transported process liquid are compatible with each other.
GBGB18001800 Liquid End Plastic Check Valves: ReassemblyLiquid End Plastic Check Valves: Reassembly
Refer to Figure 6-11
1. Fit new o-rings into the relevant position of valve body, valve seat and limited position plate.
NOTE:
To assure a tight, leak free seal, new o-rings should be used each time the check valves are
disassembled.
2. Refer to Figure 6-11, fit the valve seat, valve body, limited position plate and spring into the valve assembly.
CAUTION:
The order of assembly of the suction and discharge check valves is different.
3. Sit the ball guide on a flat surface so that the side with the ball faces upwards. Position seat on the ball
guide, trapping the ball inside. When the seat is pressed into the ball guide, the beveled edge of the seat
must be facing outward. The bevel should not face the inside of the check valve Use a flat surface such as
a board to press the seat into the ball guide with firm, even pressure.
4. Position the union end (445) onto the correct end of the ball guide. Slip the union nut (435) over the union
end and screw tightly (hand tight only) onto the ball guide.
5. Screw the valve assembly into the liquid end body (hand tight only). DO NOT OVER TIGHTEN.DO NOT OVER TIGHTEN.
GBGB18001800 Liquid End Stainless Steel Check Valves: DisassemblyLiquid End Stainless Steel Check Valves: Disassembly
Refer to Figure 6-16
1. Unscrew the three screws (441) and remove them and their three washers (439)
2. Remove the connection(445)
3. The seat (420), plate (422) and valve guide (424) should all now slip apart easily.
4. Remove the three gaskets (419).
5. Carefully clean any parts to be reused. If any chemicals are used in the cleaning process, ensure that
they are compatible with the process liquid.
GBGB18001800 Liquid End Stainless Steel Check Valves: ReassemblyLiquid End Stainless Steel Check Valves: Reassembly
Refer to Figure 6-16
1. Unscrew the three screws (441) and remove them and their three washers (439)
2. Remove the connection(445)
3. The connection (435), seat (420), plate (422) and valve guide (424) should all now slip apart easily.
4. Remove the three gaskets (419).
5. Carefully clean any parts to be reused. If any chemicals are used in the cleaning process, ensure that
they are compatible with the process liquid.
Diaphragm Assembly Replacement
It is recommended that the oil seal and diaphragm assembly be replaced at the same time. The
instructions given under "Replacing the Oil Seal" are complete instructions for replacing both the oil seal and
16

the diaphragm assembly. If you plan to replace both, refer to the" Replacing the Oil Seal" instructions, and
disregard the instructions below. These instructions are intended for use only if the diaphragm assembly is
being replaced independent of the oil seal.
Before beginning diaphragm replacement, make sure that all shut-off valves are closed and all pressure is
bled from the liquid end.
Diaphragm Assembly Identification & Limitations
Diaphragm assemblies with spanner wrench holes in the cap must be replaced as a unit, however hex
head cap (240) style may be disassembled for diaphragm replacement.
Diaphragm Assembly Removal (Refer to Figure 6-1 and 6-2)
1. Set the stroke adjusting knob to 100%.
2. Disconnect the suction and discharge piping.
3. Unscrew the six diaphragm head bolts.
4. Remove the diaphragm head assembly from the pump body.
5. Turn the motor fan by hand (remove the motor shroud if necessary) until the end of the diaphragm
assembly (261) is fully forward, and unscrew the diaphragm assembly from the connecting rod (60).
Disassembly (Only those units with a hex head diaphragm cap design)
1. Secure the hex cap (240) in a vise, and loosen the support nut (270) using a 30mm hex socket.
2. After complete disassembly inspect the support nut (270). It should be free of corrosion and clean. The
angled surface must be smooth to protect the diaphragm from damage. If the support nut does not meet
these requirements, replace it.
Reassembly (Only those units with a hex head diaphragm cap design)
1. Mount the hex cap (240) in a vise (do not over tighten), and with surfaces cleaned place a new diaphragm
(260) onto the cap as shown if figure 6-2 (contour toward the support nut).
2. The set screw (250) hand tight in the cap with the hex end visible.
3. Snug the support nut (270) onto the set screw, hand tight.
4. DO NOT OVERTIGHTENDO NOT OVERTIGHTEN the support nut. Use a 30mm hex socket an torque wrench to tighten the
support nut. The torque depends on diaphragm diameter.
Diaphragms less than 5'' O.D. (127mm): Torque is 20 inch pounds.
Diaphragm over 5'' O.D.; Torque is 30 inch pounds
Reinstallation of Assembly (Refer to Figure 6-1,6-2)
1. With the stroke adjusting knob at 100% and the diaphragm fully forward as in steps 1 and 5 above, screw
the diaphragm assembly into the connecting rod until it reaches its natural mechanical stop.
2. Turn the motor fan by hand until the diaphragm rests properly on the diaphragm support (230).Reinstall
the motor shroud if previously removed.
3. Fit the diaphragm head back into place on the pump body.
4. Torque the six diaphragm head bolts to 90 in.lb. (10Nm) in a crisscross pattern.
Replacing the Oil Seal
Before beginning oil seal replacement, make sure all shut-off valves are closed and all pressure has been
17