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CH&E and Magnum Replacement Diaphragms for Diaphragm Pumps

CH&E and Magnum replacement diaphragms for diaphragm pumps are available through Ken’s Distributing in rubber, neoprene, Buna/nitrile, TPE, and Viton compounds, with OEM-fit part numbers for 2 inch, 3 inch, and 4 inch CH&E and Magnum pump models used in construction dewatering, municipal utility work, industrial slurry transfer, agricultural applications, and flood and emergency response operations. Ken’s Distributing is an authorized CH&E dealer and stocks both individual replacement diaphragms and bulk orders of 15 units or more, with discount pricing available for contractors, distributors, and small businesses.

Use the part number tables below to identify the correct diaphragm for your pump size and application, then contact Ken’s Distributing to confirm stock and place your order.

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Available materials

Neoprene

Rubber

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Neoprene

2 Inch Magnum Replacement Diaphragm - Neoprene

2″ Magnum Replacement Diaphragm – Neoprene

3 Inch Magnum Replacement Diaphragm - Neoprene

3″ Magnum Replacement Diaphragm – Neoprene

3 Inch Magnum Replacement Diaphragm - Neoprene (No Holes)

3″ Magnum Replacement Diaphragm – Neoprene (No Holes)

Rubber

2 Inch Magnum Replacement Diaphragm - Rubber

2″ Magnum Replacement Diaphragm – Rubber

3 Inch Magnum Replacement Diaphragm - Rubber

3″ Magnum Replacement Diaphragm – Rubber

The Role of the Diaphragm in CH&E and Magnum Pumps

CH&E and Magnum diaphragm pumps are positive-displacement pumps designed to handle fluids that would damage or clog conventional impeller pumps, including water carrying sand, mud, small solids, slurry, and debris. The diaphragm is the component that makes this possible.

Each diaphragm is a flexible disc that physically separates the air chamber from the liquid chamber inside the pump body. As the diaphragm flexes through its stroke, it creates the suction that draws fluid into the pump on one stroke and the pressure that pushes fluid out through the discharge on the other. Because the diaphragm is the only barrier between the fluid and the internal drive components, it must maintain its integrity under continuous flexing, pressure cycling, and contact with whatever is in the fluid being pumped.

This is why material selection matters as much as dimensional fit. A diaphragm in the wrong compound for the fluid being pumped will fail faster, reduce pump efficiency before it fails completely, and in some cases allow fluid to reach internal components that are significantly more expensive to repair than the diaphragm itself.

Ken’s Distributing manufactures CH&E and Magnum replacement diaphragms to OEM specifications for size, thickness, and compound composition. Each diaphragm is built to match the original equipment fit for the pump model it is intended for.

Where CH&E and Magnum Diaphragm Pumps Are Used

CH&E and Magnum positive-displacement diaphragm pumps are used across a wide range of industries and applications where fluid contains solids, debris, or contaminants that conventional pumps cannot handle.

Construction dewatering and excavation drainage: Removing groundwater, surface water, slurry, and sediment-laden water from active construction sites, trenches, and excavations. CH&E and Magnum pumps are a standard choice in this environment because of their ability to pass solids without clogging.

Municipal utility maintenance and bypass operations: Supporting sewer bypass, water main repair, and stormwater management operations where the fluid may contain solids, debris, or sediment.

Agricultural irrigation and livestock water management: Moving water in irrigation systems and agricultural water supply applications where clean water handling is standard.

Industrial wastewater and slurry movement: Transferring process water, industrial slurry, and wastewater in plant and facility environments where the fluid contains suspended solids or chemical content that rules out centrifugal pumps.

Emergency flood and storm cleanup: High-volume dewatering in flood response, storm damage remediation, and emergency water removal where pump reliability under continuous operation is critical.

CH&E and Magnum vs. CH&E-Only Diaphragms

Ken’s Distributing maintains two separate pages for CH&E diaphragm replacements. This page covers diaphragms for both CH&E and Magnum pump models across the full 2 inch, 3 inch, and 4 inch size range, including the broader part number selection and alternate compound options that apply to both brands.

The CH&E Replacement Diaphragms page covers CH&E-specific pump models and is the correct starting point if your pump is a CH&E unit and you are looking for model-specific guidance on material selection and sizing.

If your pump is a Magnum unit, this page is the correct reference for part numbers and compound selection.

If you are unsure whether your pump is a CH&E or Magnum model, contact Ken’s Distributing with your pump model number and our parts team will confirm the correct page and part number for your unit.

2 Inch CH&E and Magnum Replacement Diaphragms

Compatible 2 Inch CH&E Pump Models

The 2 inch diaphragm fits the following CH&E pump models:

5401, 5402, 5403, 5405, 6401, 6402, 6403, 6405.

For complete repair kits, flappers, and related valve components for these models, see the CH&E 2 inch pump parts breakdown.

2 Inch Diaphragm Part Numbers by Compound

Part Number Compound Best Application
P2331N Neoprene Standard choice for water, slurry, and construction dewatering. Abrasion and weather resistant.
P2331R Rubber Clean water and lightly sediment-laden water in standard dewatering applications.
P2331B Buna/Nitrile Oil, fuel, and hydrocarbon-contaminated water. Correct choice when petroleum content is present.
P2331TEP TPE Extended-life compound for high-cycle, continuous-duty, or chemically demanding applications.

Alternate 2 Inch Compound Options

The following alternate part numbers are available for 2 inch CH&E and Magnum applications requiring specific compound or construction variations.

SA-10003B: Buna/Nitrile
SA-10003N: Neoprene
SA-10003V: Viton
SA-10004N: Neoprene with Cloth Insert

Note on Viton availability: Viton is a fluoroelastomer compound with superior resistance to aggressive chemicals, fuels, and high temperatures. It is not required for standard construction or dewatering applications and carries a higher cost than other compounds. Specify Viton only when the fluid being pumped would degrade Buna/nitrile or TPE. Contact Ken’s Distributing to confirm Viton availability and lead time before specifying it for your application.

Note on cloth insert diaphragms: The neoprene with cloth insert option provides additional dimensional stability and tear resistance in applications where the diaphragm experiences high physical stress during the pumping stroke.

Typical Applications for 2 Inch CH&E and Magnum Pumps

  • Light construction site dewatering and trench pumping
  • Irrigation system water supply
  • Industrial slurry pumping at lower flow volumes
  • General utility pumping in municipal and facility maintenance

3 Inch CH&E and Magnum Replacement Diaphragms

Compatible 3 Inch CH&E Pump Models

The 3 inch diaphragm fits CH&E pump models in the 5500 through 6535 range. For complete repair parts, flappers, and valve assemblies for these models, see the CH&E 3 inch pump parts breakdown.

3 Inch Diaphragm Part Numbers by Compound

Part Number Compound Best Application
P2726N Neoprene General-purpose, abrasion-resistant compound for construction dewatering and slurry transfer.
P2726R Rubber Clean water and light sludge in standard dewatering applications.
P2726B Buna/Nitrile Fuel and oil resistant for hydrocarbon-contaminated water and industrial fluid transfer.
P2726TEP TPE Extended-life compound for heavy continuous-duty use, abrasive slurry, and chemically active fluids.

Alternate 3 Inch Compound Options

SA-10001B: Buna/Nitrile
SA-10001N: Neoprene
SA-10002N: Neoprene with Cloth Insert

The neoprene with cloth insert option (SA-10002N) is worth considering for 3 inch CH&E and Magnum pumps in high-cycle construction applications where additional diaphragm tear resistance is beneficial.

Typical Applications for 3 Inch CH&E and Magnum Pumps

  • Active construction site dewatering handling higher water volumes than a 2 inch pump can manage
  • Agricultural water transfer requiring higher flow rates
  • Industrial slurry and wastewater transfer in plant environments
  • Municipal bypass operations supporting sewer and water main maintenance

4 Inch CH&E and Magnum Replacement Diaphragms

About the 4 Inch CH&E and Magnum Pump

The 4 inch CH&E and Magnum diaphragm pump is the largest size in this series and is used in large-volume dewatering, flood control, sewer bypass, and high-volume industrial slurry pumping applications where the flow capacity of a 3 inch pump is insufficient. For complete repair parts, flappers, and valve assemblies for 4 inch CH&E pump models, see the CH&E 4 inch pump parts breakdown.

4 Inch Diaphragm Part Numbers by Compound

Part Number Compound Best Application
P2157N Neoprene Chemical-resistant and abrasion-resistant for wastewater, construction slurry, and industrial fluid transfer.
P2157R Rubber Standard duty for clean water and sediment-laden water without chemical or hydrocarbon content.
P2157B Buna/Nitrile Oil and fuel resistant for hydrocarbon-contaminated fluids and petroleum-containing wastewater.
P2157T TPE Long-wear compound with broad chemical tolerance for demanding continuous-duty 4 inch applications.

Typical Applications for 4 Inch CH&E and Magnum Pumps

  • Large-volume construction dewatering where flow demands exceed 3 inch pump capacity
  • Flood control and emergency water removal requiring maximum throughput
  • Sewer bypass operations during municipal infrastructure maintenance
  • High-volume industrial slurry pumping in mining, aggregate, and industrial processing environments

Selecting the Right Compound for Your CH&E or Magnum Pump

The compound selection process is the same regardless of whether your pump is a 2 inch, 3 inch, or 4 inch CH&E or Magnum model. Match the compound to the fluid being pumped and the operating conditions.

Clean water, standard groundwater, light sediment without chemical or hydrocarbon content: Rubber or neoprene. Choose rubber for the lowest cost in clean-water applications. Choose neoprene for better outdoor durability, abrasion resistance, and flex life in active construction environments.

Construction slurry, concrete cutting wastewater, sediment-laden groundwater, outdoor pump operation: Neoprene. The abrasive particle content and outdoor operating conditions in these applications favor neoprene over rubber. The neoprene with cloth insert option provides additional tear resistance in high-physical-stress applications.

Oily wastewater, fuel-contaminated groundwater, petroleum-containing fluids: Buna/nitrile. Rubber and neoprene will degrade in contact with oil and fuel. Buna/nitrile is the correct specification for any CH&E or Magnum pump application where hydrocarbon content is present in the fluid.

Continuous-duty high-cycle operation, abrasive slurry, mild chemical exposure, demanding environments where rubber and neoprene wear out too quickly: TPE. The higher per-unit cost compared to rubber and neoprene is typically justified by fewer replacements over time in these conditions.

Aggressive chemicals, fuels, or high-temperature fluids that exceed Buna/nitrile or TPE compatibility: Viton (available for 2 inch applications via SA-10003V). Contact Ken’s Distributing to confirm Viton availability and suitability for your specific fluid before specifying it.

For applications that do not fit clearly into these categories, contact Ken’s Distributing with your pump model number and a description of the fluid being pumped. Our parts team can confirm the correct compound for your specific conditions.

When to Replace Your CH&E or Magnum Diaphragm

CH&E and Magnum diaphragm wear typically presents as gradual performance loss before a complete failure. Identifying wear early protects the internal drive components from secondary damage that is more expensive to repair than the diaphragm.

Replace or inspect your CH&E or Magnum diaphragm when you observe any of the following.

  • The pump takes noticeably longer to prime than when the diaphragm was new
  • Discharge flow drops at full throttle without a change in suction lift or discharge head
  • Air bubbles appear in the discharge stream, indicating air bypass through a compromised diaphragm
  • Visible cracking, surface stiffening, fabric showing through the diaphragm face, or permanent deformation during physical inspection
  • Fluid appearing at the air exhaust port or in the air chamber
  • Increased pump vibration during normal operation

Do not continue operating a CH&E or Magnum pump with a visibly damaged or suspected-failed diaphragm. A torn diaphragm allows fluid and debris to enter the air chamber and reach the drive components, converting a straightforward diaphragm replacement into a more involved pump rebuild.

CH&E and Magnum Diaphragm Installation and Maintenance

Installation

Confirm the part number and compound match your pump model and application before installation. Use the tables above to identify the correct part number for your pump size.

Torque the cover plate bolts evenly in a cross or star pattern to ensure uniform clamping pressure across the entire diaphragm sealing face. Uneven torque is a common cause of edge leaks and accelerated localized diaphragm wear on CH&E and Magnum pumps.

Follow the torque specifications from the CH&E parts breakdown for your specific pump model. If you do not have the parts breakdown for your model, contact Ken’s Distributing and we will provide the correct torque specification.

Inspect flappers and valve assemblies at the same time as every diaphragm replacement. Worn flappers reduce pump efficiency and can mask the performance improvement from a new diaphragm. Replace flappers and valve assemblies when the pump is high-hour or when flow has been erratic prior to the diaphragm replacement.

Maintenance

  • Inspect CH&E and Magnum diaphragms regularly for cracking, stiffening, or fabric showing through the diaphragm surface. In active construction use, inspect every 500 to 1,000 operating hours as a starting point. Adjust based on your actual operating conditions.
  • Flush the pump after handling muddy, slurry-laden, chemical-containing, or petroleum-contaminated fluid. Allowing these materials to dry inside the pump housing accelerates wear on the diaphragm, flappers, valve seats, and internal surfaces.
  • Avoid running CH&E and Magnum pumps dry. Dry running removes the fluid that cushions the diaphragm during its stroke and accelerates wear, particularly on rubber and neoprene compounds.
  • Store pumps out of direct sunlight when not in use to slow UV and ozone degradation on rubber and neoprene diaphragms.

Bulk Pricing and Blanket Orders for CH&E and Magnum Diaphragms

Contractors, rental companies, municipalities, and industrial operations running fleets of CH&E and Magnum pumps benefit from maintaining a diaphragm inventory before a failure occurs rather than sourcing parts reactively after one.

Ken’s Distributing offers bulk pricing on orders of 15 units or more across all compounds and all three pump sizes. Blanket order programs are available for organizations that need a reliable year-round supply of CH&E and Magnum replacement diaphragms without the risk of parts unavailability between orders.

Contact Ken’s Distributing with your pump model, diaphragm size, compound preference, and estimated annual volume for bulk pricing and blanket order program details.

Learn More About Blanket Orders

Related Parts for CH&E and Magnum Pumps

Diaphragm replacement is the most frequent maintenance task on CH&E and Magnum pumps, but it is rarely the only wear item that needs attention at the same time. The following related parts are commonly replaced alongside or shortly after a diaphragm replacement.

Flappers and valve assemblies: The one-way flow control components that work in combination with the diaphragm. Worn flappers reduce pump efficiency and cause erratic flow. Replace them when the pump is high-hour or when flow problems persist after a diaphragm replacement.

Complete repair kits: Ken’s Distributing carries complete repair kits for CH&E 2 inch, 3 inch, and 4 inch pumps that include the diaphragm, flappers, valve assemblies, and other wear components in a single kit. A complete kit is often more cost-effective than sourcing individual components separately, particularly for high-hour pumps.

See the CH&E 2 inch, 3 inch, and 4 inch pump parts breakdowns for complete lists of available repair parts for each pump series.

Frequently Asked Questions About CH&E and Magnum Replacement Diaphragms

The CH&E Replacement Diaphragms page focuses on CH&E-specific pump models and material selection guidance for CH&E pumps. This page covers the full part number catalog for both CH&E and Magnum pump models across the 2 inch, 3 inch, and 4 inch size range, including alternate compound options and Viton availability. If your pump is a Magnum model, this is the correct page for part number selection.

Yes. Ken’s Distributing is an authorized CH&E dealer. This means our parts team works directly with CH&E and can confirm fit, material compatibility, and availability for both current production and legacy CH&E and Magnum pump models.

Neoprene is the most commonly specified compound for CH&E and Magnum pumps in construction dewatering, slurry transfer, and outdoor applications. TPE is specified when continuous-duty operation or demanding conditions require the longest available service life. Buna/nitrile is required when the fluid contains oil or fuel.

Viton is a fluoroelastomer compound with superior resistance to aggressive chemicals, fuels, and elevated temperatures compared to Buna/nitrile and TPE. It is available for 2 inch CH&E and Magnum applications via part number SA-10003V. Viton is not required for standard construction or dewatering applications and carries a higher cost than other compounds. Contact Ken’s Distributing to confirm whether Viton is necessary for your specific fluid and application before specifying it.

A cloth insert diaphragm has a fabric layer embedded within the diaphragm body that provides additional dimensional stability and tear resistance compared to a standard diaphragm. Cloth insert options are available in neoprene for both 2 inch (SA-10004N) and 3 inch (SA-10002N) CH&E and Magnum applications. They are worth specifying in high-cycle applications where the diaphragm experiences significant physical stress during the pumping stroke and tear resistance is a priority.

Yes, in most cases. The part numbers listed above cover the same physical dimensions across multiple compounds, so changing the compound does not require modifying the pump. Always confirm that the replacement compound is appropriate for the fluid being pumped before changing materials. Ken’s Distributing can assist with compound selection for your specific application.

The size refers to the pump’s discharge port diameter. Confirm your pump’s discharge port size from the pump nameplate or model number. If you cannot determine the size from the pump itself, contact Ken’s Distributing with your CH&E or Magnum pump model number and we will confirm the correct diaphragm size.

Yes. Ken’s Distributing ships CH&E and Magnum replacement diaphragms to all 50 U.S. states and Canada. Contact us for shipping details on bulk or blanket orders.

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