MDM Sequence 750 Manual

© MDM INCORPORATED
WWW.MDMINC.COM
Reliable. Efficient.
PROUDLY MADE
IN THE USA
®
750
INSTALLATION AND SERVICE MANUAL
Model 3600SEQ12 4200SEQ12
INLET 2” 2”
DISCHARGE 1.5” 1.5”
MAX FLOW (GPH) 3600 4200
MAX HEAD (FEET) 12’ 12’
MAX POWER (WATTS) 142 154
MAX CURRENT (AMPS) 1.25 1.39
@(VOLTS) 115 115
MOTOR HP 1/8 1/8
MOTOR ENCLOSURE TEFC TEFC
IMPELLER 8 9
XXXXSEQXX
S/N: XXXX-XXXXXX
P.1
Read this manual completely before you install or operate your new pump. This is an external “out-of-pond” pump.
It is not submersible. Do not allow this pump to become submerged. Never run dry. Maximum case pressure - 25 PSI.
TYPE: STRAIGHT CENTRIFUGAL
MOTOR: INDUSTRIAL DUTY 1/8 HP, 1 PHASE, TEFC
1725 RPM (@60HZ), 115 VAC MOTOR
8 FT 3-PRONGED CORD
INLET: 2” FNPT
DISCHARGE: 1-1/2” FNPT
MATERIAL: 40% GLASS-FILLED POLYPROPYLENE
WITH NORYL®IMPELLER
HARDWARE: STAINLESS STEEL
OPTIONS: SALTWATER SERVICE
ACCESSORIES: 90 CUBIC INCH STRAINER BASKETS (1.5” & 2”)
500 CUBIC INCH STRAINER BASKET (2”)
SWING CHECK VALVES (1.5”, 2”, 3”)
®
*MOTORS ARE SUBJECT TO CHANGE DUE TO
AVAILABILITY OR SPECIFICATION REQUIREMENTS.
FILL IN FOR FUTURE REFERENCE:
MODEL: ______________________________
SERIALNUMBER:_______________________
DATEPURCHASED:______________________
COMPLETE AND MAIL YOUR WARRANTY REGISTRATION
CARD INCLUDED WITH THIS PRODUCT OR FILE ONLINE AT:
WWW.MDMINC.COM/PUMP-REGISTRATION

© MDM INCORPORATED
WWW.MDMINC.COM
Reliable. Efficient.
PROUDLY MADE
IN THE USA
®
750
We congratulate you on your choice of the Sequence®750 centrifugal pump. Its leading edge design provides you with high output at a minimal operating cost. It
is carefully constructed to give you long term, reliable service. To insure proper performance, we urge you to carefully follow the instructions in this manual. If you
have any questions, please call your supplier for assistance or visit www.mdminc.com/support.
INSTALLATION
Please read carefully. When properly installed, the Sequence®750 will provide dependable, trouble-free service.
1. Do not submerse the unit in water - it is not a submersible pump. Do not allow the pump to become submerged during transient periods, such as heavy rain, run-off, etc.
2. Locate the pump as near the water source as possible. A flooded suction is preferred.
3. The pump is not self-priming. Therefore, if the fluid level is below the pump, a swing check valve must be installed below water level. The pump and inlet line
must be primed prior to start up. A strainer basket is recommended for non-flooded installations.
4. Mount the motor base to a secure, immobile foundation.
5. Use only plastic fittings on both the inlet and discharge ports. Seal the inlet and discharge fittings with Teflon®pipe dope. These fittings should be self-
supported and in neutral alignment with each port (i.e., Fittings must not be forced into port alignment which may cause premature line failure or damage to
the pump volute).
6. Never restrict the inlet. Keep both inlet and discharge lines as free of elbows and valves as possible. Always use pipe of adequate diameter. This will reduce
friction losses and maximize output. Never use an inlet line of smaller diameter than the discharge line. Minimize the suction lift.
ELECTRICAL HOOK-UP
Carefully examine the power cord before use. Do not use this power cord if there is any visible damage. Do not use this power cord in water or if the motor or
electrical receptacle is in contact with any standing water. This power cord should only be plugged into a properly installed 115 VAC GFI receptacle. Always test
cycle a GFI receptacle to determine its condition before use.
PUMPPUMP
BALL VALBALL VALVEVE
BALL VABALL VALVLVEE
SUCTION LIFTSUCTION LIFT
FLOODED SUCTIONFLOODED SUCTION
SWING CHECK VASWING CHECK VALVLVEE
P.2
WARNING: DO NOT RUN DRY
WARNING: ALWAYS SHUT OFF ELECTRICAL POWER BEFORE INSTALLATION AND / OR SERVICING THIS PUMP.
ALL ELECTRICAL WIRING SHOULD MEET STATE AND LOCAL ORDINANCES. THE SEQUENCE®750 PUMP MOTOR IS DESIGNED FOR
115 VAC 60HZ POWER ONLY. 230V 50HZ MOTORS ARE AVAILABLE. CONTACT YOUR SUPPLIER FOR INFORMATION.

© MDM INCORPORATED
WWW.MDMINC.COM
Reliable. Efficient.
PROUDLY MADE
IN THE USA
®
750
PUMP END ASSEMBLY
1. Inspect all pump parts (O-ring, O-ring groove, impeller hub ID, motor shaft, etc.) and clean if necessary.
2. Apply sealant to the bracket bore ID wall and around the seal case - follow sealant manufacturer’s instructions. We recommend using Gasgacinch®. Silicone
sealant can also be used.
3. Press the carbon graphite seal into the bracket while taking care not to touch or damage the carbon graphite face. Never touch or apply pressure to the carbon
graphite seal face.
4. Screw the (4) M-Bolts five complete turns into the threaded holes located on the motor face.
5. Mount the bracket to the motor by aligning the key holes over each bolt head, then rotate clockwise which will position the small key hole slot under each bolt
head. Tighten each bolt with a wrench to secure the bracket to the motor (8-25 inch-pounds force).
6. Carefully, lubricate the seal seat elastomer OD and impeller hub ID with water. Press the seal seat into the impeller hub making certain that the ceramic is in
evenly - the sealing surface should be parallel with the impeller hub.
7. Apply clean water to the carbon-graphite and seal seat sealing surfaces. Do not use silicon lubricants or grease.
8. Lock the shaft by placing a screwdriver blade into the shaft slot at the fan end of the motor. Thread the impeller onto the motor shaft. Thread until the impeller
securely contacts the shaft shoulder.
9. Seat the large O-ring into the bracket O-ring groove.
10. Assemble the volute onto the bracket with (6) P-Bolts (10-24 x 2 ¾”carriage bolts) and (6) flanged lock nuts. Tighten in a cross pattern (30 lb. in.).
11. Install the drain plug and O-ring, into the volute drain hole.
12. Before operating the Sequence®750, allow a proper cure time for the sealant used in step 2.
DISASSEMBLY
1. Shut off power to the motor before servicing any pump.
2. Unplug the power cord.
3. Disassemble the volute from the bracket (6) P-Bolts and (6) flanged lock nuts. The volute may remain attached to the plumbing to help simplify reinstallation.
4. Lock the shaft by placing a screwdriver blade into the shaft slot at the fan end of the motor. Unthread the impeller from the motor shaft.
5. Remove the ceramic seal seat, with rubber boot, from the impeller hub (if you are replacing the seal).
6. Loosen the (4) M-Bolts attaching the bracket to the motor. Rotate the bracket counterclockwise until the screw heads are located in the large key hole slots.
Lift off the bracket from the motor.
7. Remove the carbon-graphite seal assembly from the bracket by pressing it out from the motor-side of the bracket. Do not pry it out with a screwdriver from the
pump cavity side of the bracket (if you are replacing the seal).
NO. DESCRIPTION SEQUENCE®P/N
1 DRAIN PLUG 1000.110
2 O-RING (DRAIN PLUG) E014B70
3 VOLUTE 750.070
4 LARGE O-RING 750.061
5 IMPELLER 750.05__*
6 SS SEAL 750.0414
7 BRACKET 750.030
8 SLINGER 750.010
9 HARDWARE KIT:
(6) P-BOLT, (6) FLANGED LOCK NUT AND WASHER, (4) M-BOLT
750.502
Note: These part numbers are only for standard models within the Sequence®750 series.
*750.05__ Reference page one for Impeller number (8 and 9).
P.3
2.1”
7.0”
12.7”7.9”
2.19”
1.5” FNPT
DISCHARGE
2”
FNPT
INLET
Motor illustration is for reference only.
3.08”
VOLUTE
IMPELLER
BRACKET
M BOLT
FLANGED
LOCK NUT &
WASHER
LARGE
O-RING
SS SEAL
P-BOLT
DRAIN PLUG
& O-RING
SLINGER
1
2
3
4
5
6
9
9
8
9
7

© MDM INCORPORATED
WWW.MDMINC.COM
Reliable. Efficient.
PROUDLY MADE
IN THE USA
®
750
MAINTENANCE
Lubrication
Motor - Permanently Lubricated ball bearings - no service required.
Rotary Seal - Requires no lubrication after assembly.
SYMPTOM PROBLEM RESOLUTION
No Flow
Insufficient Prime Prime system with water and purge all air from suction piping.
Install check valve.
Insufficient Power Verify power supply and connection from panel to pump.
Verify proper voltage. Some models are dual voltage (115/230).
Flow Restriction
Ensure valves are open.
Ensure plumbing is clear, including suction strainers, check valves, etc.
Verify check valve orientation and direction of permitted flow.
Clean out leaves or other debris from basket strainer (if applicable).
Air leak Fix air leaks at fittings, connections, strainer basket etc. This typically occurs on the intake side.
System Incompatibility Verify hydraulic compatibility: i.e. pump and pipe are sized for the system.
Low Flow
Air leak Fix air leaks at fittings, connections, strainer basket etc. This typically occurs on the intake side.
System Incompatibility Verify hydraulic compatibility: i.e. pump and pipe are sized for the system.
Insufficient Power Verify power supply and connection from panel to pump.
Verify proper voltage. Some models are dual voltage (115/230).
Flow Restriction
Ensure valves are open.
Ensure plumbing is clear, including suction strainers, check valves, etc.
Clean out leaves or other debris from basket strainer (if applicable).
Insufficient Prime Prime system with water and purge all air from suction piping.
Cavitation
Verify airtight plumbing on the suction plumbing especially fittings.
Clean out leaves or other debris from basket strainer (if applicable).
Increase pipe size where possible.
Decrease suction pipe length, reduce the number of elbows, etc.
Verify hydraulic compatibility: i.e. pump and pipe are sized for the system.
Sporadic Operation
Insufficient Power Verify power supply and connection from panel to pump.
Verify proper voltage. Some models are dual voltage (115/230).
Poor Ventilation Ensure adequate airflow over motor to prevent overheating.
Excessive Noise
Cavitation
Verify airtight plumbing on the suction plumbing especially fittings.
Clean out leaves or other debris from basket strainer (if applicable).
Increase pipe size where possible.
Decrease suction pipe length, reduce the number of elbows, etc.
Verify hydraulic compatibility: i.e. pump and pipe are sized for the system.
Insufficient Power Verify power supply and connection from panel to pump.
Verify proper voltage. Some models are dual voltage (115/230).
Flow Restriction
Ensure valves are open.
Ensure plumbing is clear, including suction strainers, check valves, etc.
Verify check valve orientation and direction of permitted flow.
WARNING: EYE PROTECTION IS STRONGLY RECOMMENDED
*The pump must be drained before servicing or if stored below freezing
temperatures. Periodic replacement of seals may be required due to normal
carbon wear.
MDM INCORPORATED
3345 N. Cascade Ave • Colorado Springs, CO • 80907
Phone [phone] • Fax [phone]
www.mdminc.com • [email protected]
P.4
Gasgacinch®is a registered trademark of Porter Manufacturing.
Noryl®is a registered trademark of the General Electric Company.
Teflon®is a registered trademark of the Chemours Corporation.
Sequence®is a registered trademark of MDM Incorporated.
Sequence 750 Installation Manual 2020.indd. Adobe Indesign CC. Updated 10/12/20.