Oberdorfer 700DP Bronze Centrifugal Pump End – 4.25" Impeller, Pump End Only, No Motor Included
Built on more than a century of fluid handling expertise, the Oberdorfer 700DP is a close-coupled bronze centrifugal pump end designed for professionals who need reliable, consistent performance across a wide range of liquid transfer applications. This unit is sold strictly as a pump end only (PEO) — it has no electrical components, no motor, and no phase rating of its own. The "3PH" notation appearing in the Oberdorfer catalog part number is not an electrical specification of the pump end itself; it is simply a motor pairing designator indicating this pump end is cataloged for use with a three-phase NEMA 56J C-Flange Jet Pump Motor. The pump end is mechanically compatible with either single-phase or three-phase NEMA 56J motors — the installer supplies and selects the appropriate motor for the application. The 4.25-inch bronze impeller sits at the larger end of the 700 series range, delivering strong flow output well suited to demanding transfer duties in water treatment, HVAC systems, agriculture, chemical processing, and general industrial fluid handling.
What sets this pump apart is the combination of a corrosion-resistant cast bronze housing, a 416 stainless steel shaft, and a carbon/ceramic mechanical seal with a Nitrile rubber element. The seal handles water, oils, and mild solvents up to 212°F and 75 PSI, while optional fluoroelastomer (Viton) or PTFE seal upgrades are available for higher-temperature or chemically aggressive service. Because centrifugal pumps inherently operate without contact between the impeller and casing walls, the result is quiet, smooth, low-maintenance fluid transfer. There is no need for a pressure relief valve, and flow can be easily controlled by throttling the discharge line — a practical advantage for any installation where flow management matters.
Key Features
- Pump end only (PEO) — no motor, no electrical components, no phase rating
- "3PH" in the part number is a catalog motor pairing designator only, not an electrical specification of the pump end
- Compatible with standard NEMA 56J C-Flange Jet Pump Motor, single or three phase (motor not included)
- 4.25-inch single-stage bronze impeller for high-flow performance
- Cast bronze housing for superior corrosion resistance
- 416 stainless steel shaft for durability and broad chemical compatibility
- Standard carbon/ceramic mechanical seal with Nitrile (Buna) element
- Optional Viton (S10) or PTFE (S11) seals available for chemically demanding service
- Discharge line can be throttled without need for a pressure relief valve
- Impeller attaches directly to motor shaft for a compact close-coupled design
- Shim kit included to accommodate varying motor shaft projections
- Not self-priming — flooded suction or foot valve required
Applications
- Industrial water transfer and recirculation systems
- HVAC and building services fluid handling
- Agricultural water supply and irrigation
- Chemical processing with compatible fluids
- Light oil and solvent transfer within temperature and chemical ratings
- General industrial OEM and replacement pump end installations
Specifications
- Model Number: 700DP
- Configuration: Pump End Only (PEO) — No Motor Included
- Impeller Diameter: 4.25 inches
- Impeller Material: Bronze
- Housing Material: Cast Bronze
- Shaft Material: 416 Stainless Steel
- Mechanical Seal: Carbon/Ceramic with Nitrile (Buna) element — standard
- Optional Seals: Viton/Fluoroelastomer (S10), PTFE (S11)
- Motor Compatibility: Standard NEMA 56J C-Flange Jet Pump Motor (not included); compatible with single-phase or three-phase motors
- Note on "3PH" in Part Number: Catalog motor pairing designator only — not an electrical rating of the pump end
- Maximum Temperature: 212°F (100°C) with standard Nitrile seal
- Maximum Pressure: 75 PSI
- Inlet Port Size: 1-1/4 inch NPT
- Outlet Port Size: 1 inch NPT
- Priming: Not self-priming; requires flooded suction or foot valve
- Suction Lift: Up to 15 feet with foot valve and manual air bleed
- Recommended Motor Speed: 3450 RPM
Frequently Asked Questions
Q: The part number says "3PH" — does that mean this pump end only works with a three-phase motor?
No. The pump end itself has no electrical components and carries no phase rating. The "3PH" notation in the Oberdorfer catalog part number is simply a motor pairing designator used for ordering and catalog classification purposes. The pump end is mechanically compatible with both single-phase and three-phase NEMA 56J C-Flange motors. The installer selects and supplies the appropriate motor for the specific application and power supply available.
Q: Does the Oberdorfer 700DP ship with a motor?
No. This is a pump end only (PEO). The motor is not included and must be sourced separately. You will need a NEMA 56J C-Flange Jet Pump Motor with a weld-on base and threaded shaft end. When using a three-phase motor, always verify rotation direction at installation — interchanging any two wires on a three-phase circuit reverses rotation. Single-phase motors are pre-wired for the correct counter-clockwise rotation when viewed from the inlet end.
Q: What liquids is the Oberdorfer 700DP compatible with using the standard seal?
With the standard carbon/ceramic Nitrile mechanical seal, the pump handles water, water solutions, light oils, and mild solvents at temperatures up to 212°F and pressures up to 75 PSI. For aggressive chemicals, elevated temperatures, or severe solvents, the optional Viton (S10) or PTFE (S11) seal upgrades are available. Contact the factory with specific fluid compatibility questions.
Q: Why is the 700DP not self-priming, and how do I work around this?
Centrifugal pumps in this series require liquid to be present in the casing before starting — they cannot draw fluid up from a dry suction line on their own. The preferred installation is below the liquid level with a flooded suction. If that is not possible, install a foot valve at the beginning of the suction line and manually bleed all air from the pump casing before startup. This allows suction lift of up to 15 feet, though reliable starting depends entirely on the foot valve maintaining a leak-free seal.
Q: How do I set the correct impeller clearance when mounting the 700DP to a motor?
Oberdorfer includes a shim kit with the pump head to account for differences in motor shaft projection lengths across manufacturers. Set an air gap of 0.010 to 0.015 inches between the rear shroud of the impeller and the motor adapter face. After mounting, rotate the shaft by hand to confirm the impeller spins freely without contacting the casing, and adjust shimming as needed before first operation.
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