Oberdorfer 405M-04 Bronze Flexible Impeller Pump End – General Purpose & Sewage Transfer
The Oberdorfer 405M-04 is a close-coupled bronze flexible impeller pump end built for dependable general purpose and sewage transfer service across a wide range of industrial, municipal, and facility applications. Sold as a pump end only — without a motor — it is designed to mount directly onto a NEMA C 56C face motor using an aluminum adapter plate, making it a practical choice for replacement, system integration, or custom build-outs. The all-bronze housing delivers strong corrosion resistance, while the stainless steel shaft ensures long-term mechanical durability even in demanding wet environments.
With a maximum flow rate of 25 GPM and a single neoprene rubber impeller providing the pumping action, the 405M-04 keeps things simple — just one moving part means reduced maintenance and easy serviceability over time. It is self-priming, capable of achieving a suction lift of up to 15 feet when fully primed, and can operate in either rotational direction, which adds installation flexibility. The pump handles fresh water, salt water solutions, mild chemicals, wastewater with light solids in suspension, and condensate removal — making it well suited for sewage treatment facilities, carpet extraction equipment, general fluid transfer stations, and similar applications where reliability and straightforward serviceability matter most.
Key Features
- All-bronze housing for maximum corrosion resistance
- Single moving part — neoprene rubber flexible impeller for simplicity and easy maintenance
- Stainless steel shaft for long-term durability
- Self-priming design — suction lift up to 15 feet when fully primed
- Bi-directional operation — pumps in either rotational direction
- Mechanical seal with Buna elastomer for positive sealing
- Close-coupled design mounts directly to NEMA C 56C face motor
- Easy impeller replacement without full pump replacement
- Flow may be throttled or shut off briefly without a relief valve
Applications
- General purpose liquid transfer
- Sewage and wastewater transfer with light solids in suspension
- Condensate removal
- Carpet extraction and cleaning equipment
- Fresh and salt water transfer
- Mild chemical solutions
- Industrial fluid handling
Specifications
- Part Number: 405M-04 / OB405M-04
- Pump Type: Close-Coupled Flexible (Rubber) Impeller Pump End
- Maximum Flow Rate: 25 GPM
- Maximum Pressure: 43 PSI (7 GPM at 100 ft head)
- Inlet Port: 1" NPT / 1-1/2" Hose
- Discharge Port: 1" NPT / 1-1/2" Hose
- Seal Type: Mechanical seal, Buna elastomer
- Impeller Material: Neoprene rubber (Nitrile/Buna N available)
- Housing Material: Bronze
- Shaft Material: Stainless steel
- Motor Mount: NEMA C 56C face motor (motor not included)
- Maximum Shaft Speed: 1,750 RPM
- Liquid Temperature Range: 40°F to 180°F (standard neoprene); 40°F to 140°F (recommended operating)
- Suction Lift: Up to 15 feet (fully primed)
- Motor Required: Not included — pump end only
Frequently Asked Questions
Q: Is the motor included with the Oberdorfer 405M-04?
No. The 405M-04 is a pump end only. The motor is sold separately. It is designed to mount onto a NEMA C 56C face motor using an aluminum adapter plate, which is included with the pump end.
Q: Can the Oberdorfer 405M-04 be used for sewage or wastewater applications?
Yes. This pump is well suited for transferring wastewater and light sewage with solids in suspension. Oberdorfer flexible impeller pumps are specifically used in sewage treatment plant operations to move wastewater and light sludge. It should not be used for thick sludge, gasoline, strong solvents, or acids.
Q: Does this pump require priming before the first use?
Yes. On initial startup the pump must be primed with liquid before operation. The neoprene impeller relies on the liquid being pumped for lubrication — running it dry even briefly will degrade the impeller rapidly. Once primed, the pump is self-priming and can achieve a suction lift of up to 15 feet.
Q: Can the 405M-04 pump in both directions?
Yes. The pump operates in either rotational direction with equal efficiency. The direction of shaft rotation determines which port acts as inlet and which acts as discharge. Before installation, manually rotate the pump in the intended direction of rotation to properly set the flexible impeller blades.
Q: What impeller options are available for the Oberdorfer 405M-04?
The standard impeller is neoprene rubber, suitable for fresh water, salt water, and mild water-based solutions. A nitrile (Buna N) impeller is available as an alternative for applications involving oil-contaminated water or kerosene, though with a reduced service life compared to standard neoprene service.
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