AODD Pump FAQS

    Find answers to common questions about air-operated double-diaphragm (AODD) pump selection, usage, maintenance, and troubleshooting



    Q: How much does the pump I want cost?
    A: Sandpiper does not directly provide pricing for pumps, as all pumps are sold by our expert distributors who can help you determine the best fit for your needs. Feel free to find your nearest local distributor, or contact us if you have more general questions on choosing the right pump.

    Q: How do I purchase a Sandpiper pump?
    A: All Sandpiper pumps are selected, sold, and supported by the best distribution network of any AODD pump manufacturer. Find a distributor near you who can help you purchase the pump you’re looking for.

    Q: Where can I find information about my pump?
    A: Sandpiper provides extensive information about your pump, everything from pump curves and specifications to installation videos and manuals. Check here for more information about specific pumps or look at our literature gallery to see all our available resources including older archived models.


    Q: What are the benefits of AODD pumps?
    A: AODD pumps are versatile and capable of handling a wide array of substances from water to volatile and dangerous liquids without requiring electricity. They are advantageous for applications that may run dry, require suction lift, flooded suction, or submerged operations. Their seal-less design eliminates the need for mechanical seals, reducing the risk of leaks and simplifying maintenance.

    Q: How much do AODD pumps cost?
    A: The cost of AODD pumps varies based on materials and construction, but they are generally affordable compared to other equivalent technologies. This affordability, combined with local inventory availability, reduces lead times. However, efficiency and performance should be prioritized over initial cost for long-term savings and productivity.

    Q: What information do I need to know before I select an AODD pump?
    A: When selecting an AODD pump, consider these 10 critical factors:

    1. Liquid Type: Identify the substance you're pumping and use resources like the SANDPIPER Chemical Compatibility Guide to choose appropriate materials.
    2. Flow Rate: Determine the required gallons per minute (gpm), with SANDPIPER pumps covering 1 to 310 gpm.
    3. Discharge Pressure: Consider the pressure on the discharge side, with SANDPIPER pumps handling 0 to 100 PSI. For higher pressures, consult for specialized pumps.
    4. Temperature: Note the liquid's temperature, especially if it's below 32 degrees Fahrenheit or above 180 degrees Fahrenheit, and consult with SANDPIPER engineers for guidance.
    5. Volatility: For volatile substances (e.g., gasoline, methyl chloride), extra precautions are necessary. Contact an engineer for advice on handling these materials.
    6. Viscosity: Assess the liquid's viscosity. For substances above 50,000 SSU, seek engineering advice.
    7. Abrasiveness: Identify if the liquid contains abrasive elements, which may require a heavy-duty pump with specific materials.
    8. Solids: Check for solid content and size, ensuring the pump can handle the maximum solid size.
    9. Suction Conditions: Understand the suction conditions (lift, flooded suction, or submersible) to select the appropriate pump setup.
    10. Compressed Air: Ensure compressed air is available for pump operation, using a filter/regulator to maintain optimal pressure and efficiency.

    These considerations are crucial for choosing a pump that meets the specific needs of any application, ensuring efficient, reliable operation.
    Q: In what mining applications can I use an AODD pump?
    A: AODD pumps are versatile and essential in the mining industry, serving in numerous applications such as general fluid transfer, loading/unloading of various chemicals and materials, and specific mining methods including underground, open surface, placer, and in-situ mining of coal and precious metals. They are also vital for filter press operations, dewatering and sump tasks, filling tires with liquid ballast, lubricating mining equipment, fuel transfer and dispensing, and the leaching process for metal extraction. This wide range of uses highlights an AODD pump’s adaptability to different mining needs, from handling viscous slurries to managing crucial operational substances like fuel, lubricants, and leaching chemicals.

    Q: I’m concerned about safety. How do I protect against potential explosive conditions? 
    A: For environments where safety and the risk of explosions are concerns, opting for ATEX-certified pumps is essential. SANDPIPER manufactures ATEX-compliant AODD pumps and accessories that are fully groundable and spark-free, eliminating the risk of static electricity build-up and ensuring safe operation in potentially explosive settings. We also provide UL-listed pumps for the secure transfer of flammable liquids. It's crucial to understand the specific conditions of your application and consult with our team to ensure the selected pump meets safety requirements.

    Q: How can I check if an AODD pump can be used with specific fluids?
    A: AODD pumps can be customized with various materials and elastomers to suit different fluids. Our Chem Guide can assist in selecting appropriate materials for specific applications.

    Q: Can AODD pumps pass line-size solids? 
    A: AODD pumps, particularly heavy duty flap valve pumps, can effectively handle fluids with debris, including line-size solids, without clogging. These pumps range from 1" to 3" and are designed with top suction and bottom discharge to prevent blockages. Available in various materials, they meet chemical compatibility needs and are lightweight for easy mobility, making them ideal for industries like mining, food processing, and waste disposal.

    Q: What are some common items that users overlook during the purchase, installation, or operation of a pump?
    A: Users often fail to consider the full scope of their application requirements when selecting a pump, such as the material's temperature, chemical compatibility, and the conditions of suction and discharge. Misestimating these factors can lead to suboptimal pump performance. A common misconception relates to the pump's capacity, where users expect performance figures (e.g., 150 gpm) that may not apply to their specific conditions due to variances in application, leading to discrepancies in expected versus actual flow rates. Consulting with the SANDPIPER team is recommended to address these mismatches and possibly upsize the pump to meet flow requirements.


    Q: Can I use the pump right out of the box? What do I need to know to install it?
    A: Before using an AODD pump, it's essential to follow the installation guide carefully to avoid issues or premature failure. Key steps include 

    1. Position the pump close to the fluid source with minimal suction line length.
    2. Avoid diameter reduction of suction line.
    3. Ensure the air supply is adequate and within pressure limits.
    4. Determine whether to lubricate the air valve and if so, use it minimally.
    5. Use a dryer to control moisture in the air line and minimize the potential for a pump malfunction.
    6. Be sure to prime the pump correctly by gradually increasing air flow to avoid cavitation and achieve efficient operation.

    Q: How can I control the flow rate in an air-operated pump?
    A: The flow rate in air-operated pumps can be easily controlled using a filter regulator, which also protects the pump by removing contaminants from the air and allows for a soft start, reducing stress on the pump.

    Q: Does a pump that uses more air volume also use more energy?
    A: Air-operated pumps do require significant air pressure and volume, making the air compressor a key factor in operating costs. Efficient pumps can lead to significant energy savings over time, especially considering that the largest cost over a pump's lifetime is the energy required to power it.

    Q: What is the maximum viscosity that can be transferred by an AODD pump?
    A: AODD pumps can handle fluids up to 90,000 cst (415,500 ssu), with options available for even more viscous substances. Adjustments such as using weighted valve balls, oversizing the pump, and gravity-feeding can enhance performance with viscous fluids.

    Q: How important is air preparation for an AODD pump?
    A: Clean, dry, compressed air is crucial for AODD pump operation. Contaminants like dirt and moisture can cause the pump to malfunction or not start, posing risks to the air and pilot valves. Using an air filter/regulator combination can eliminate these contaminants, ensuring efficient pump operation, particularly in mining environments. Proper air supply regulation and adherence to recommended air line sizes are also key to maintaining optimal performance across the pump's duty points.

    Q: Do I need to check the torque of the pump’s bolts?
    A: Always verify the tightness of an AODD pump's hardware upon installation or after repair, as hardware can loosen due to material creep, vibrations, or temperature changes. Torque specifications are provided in service manuals, ensuring the pump is not under pressure when adjusting.


    Q: In terms of preventative pump maintenance, what actions can users take?
    A: The approach to preventative maintenance typically involves allowing the pump to fail once to understand its operational lifespan under specific conditions. This failure serves as a baseline for determining the maintenance schedule. Observing the pump's performance over an initial period of five to six months provides valuable insight into its durability and maintenance needs, allowing users to plan for timely interventions based on observed operational life spans.

    Q: What are the main key factors for pump maintenance?
    A: Routine maintenance is crucial for AODD pump longevity, focusing on wear components like diaphragms, balls, seats, and flaps. Maintenance kits simplify this process, although individual parts are also available.

    Q: How do I know when to replace my pump’s components or when it might fail?
    A: To determine the lifespan of your pump's components and predict potential failures, it's advisable to initially run the pump until failure under typical conditions. This approach helps establish a baseline for the pump's operational lifespan, allowing for more accurate maintenance scheduling. When maintenance is due, replacing all wet-side components as per the SANDPIPER repair kit recommendations is crucial to minimize downtime and ensure reliability.

    Q: What should be checked in older pumps?
    A: For older pumps, especially those handling non-abrasive fluids like water, it's crucial to inspect the metal components for wear and erosion, akin to how rivers wear down rocks. This erosion can lead to sharp edges where check balls sit, deteriorating these balls and other parts like the outer diaphragm plate and the sealing edge of the outer chamber. These areas are susceptible to creating premature wear and failure, emphasizing the need for regular inspections to prevent unexpected breakdowns.


    Q: What are some of the most common problems with AODD pumps and their causes?
    A: AODD pumps frequently encounter issues due to diaphragm wear, signaled by product leakage through the pump's exhaust, a clear indication of a diaphragm failure, the most typical problem arising from natural wear. Another prevalent issue involves air-side wear, characterized by the pump stalling and releasing excessive air through the exhaust, which is often caused by dirt and debris entering through the air supply. This particular problem can be easily remedied with the installation of air filters or regulators to clean the incoming air.

    Q: How can you fix those AODD pump problems?
    A: Addressing diaphragm failure involves isolating the pump, dismantling it, and replacing the worn diaphragms, and it is also advisable to replace the balls and seats during this process. Utilizing complete air-side and wet-side repair kits is recommended for such repairs. To reduce downtime, it is suggested that users maintain a stock of one or two spare kits for quick replacement and repair, ensuring the pump's swift return to operational status following unexpected failures. Refer to the SANDPIPER kit look up tool to find the best kit for your pump model.

    Q: I’m pumping an abrasive liquid slurry. The diaphragms fail within weeks. Is there a solution for longer diaphragm life? 
    A: Pumping abrasive slurries can lead to rapid diaphragm wear. To extend diaphragm life, first, ensure the diaphragm material is chemically compatible with the liquid using our Chemical Compatibility Guide. For acidic or abrasive liquids, consider durable materials like Santoprene. If compatibility isn't an issue but wear persists, switching to a heavy duty ball style pump with a down-ported manifold configuration can prevent slurry accumulation and reduce abrasive wear. Additionally, upsizing the pump and operating it at a slower rate can improve the diaphragm and pump longevity by reducing stroke frequency and enhancing energy efficiency.

    Q: When a diaphragm fails, the process liquid may leak out of the pump and become a safety concern. How can I protect against that? 
    A: To mitigate the risk of leaks when a diaphragm fails, which can be a significant safety concern, the pump's exhaust can be piped to a safe location, sump, or vessel to capture any leaked fluid. For handling aggressive chemicals, utilizing a containment duty pump is recommended. These pumps feature a specialized design to contain and manage leaks, ensuring that hazardous materials do not escape into the environment, thus enhancing workplace safety and environmental protection.

    Q: What does it mean if the pump stalls out and blows excessive air out of the exhaust?
    A: This issue typically indicates air-side wear due to dirt and debris entering through the air supply. Installing an air filter/regulator can prevent such problems by keeping the air supply clean and free from contaminants.

    Q: What does it mean if process fluid is coming out of the exhaust side of the pump?
    A: Leaking fluid from the exhaust suggests a failed diaphragm, the most common failure in AODD pumps due to natural wear. It's essential to replace the diaphragm to stop the leak and restore proper pump function.

    Q: What should I do if the diaphragm fails prematurely (before 10 million strokes)?
    A: Premature diaphragm failure can result from issues with temperature, chemical compatibility, or system conditions. Check for diaphragm damage and ensure compatibility with the pumped fluid's temperature and chemical properties. Address suction line restrictions and air-side wear, such as oval-shaped diaphragm bolt holes, to improve diaphragm longevity.

    Q: What if my AODD pump is sluggish, stalls, or runs with low flow?
    A: These symptoms often point to inadequate airflow. Ensure your air compressor provides sufficient pressure (PSI) and volume (SCFM) according to the pump's performance curve. Also, use separate air lines for each pump to avoid shared pressure drops.

    Q: What if my AODD pump does not operate or cycle?
    A: No cycling or continuous air exhaust without pumping action can indicate fluid in the air side, a clogged or frozen air exhaust, or over-lubrication. Check and replace the diaphragm if ruptured, ensure proper torque on the diaphragm plate assembly, clean or de-ice the muffler element, and manage air-line moisture. SANDPIPER pumps generally do not require lubrication, except in specific scenarios like nitrogen-powered pumps.

    Q: What should I do if my AODD pump cycles only once and then stops?
    A: This issue may arise from an incorrectly installed air valve gasket or clogged pilot valve orifice. Ensure the gasket is correctly aligned and clean any debris from the pilot valve to resolve the problem.

    For more AODD pump installation and troubleshooting information, visit the Technical Resources section of our website or check out AODD pump troubleshooting posts on our blog. You can also reach out to a SANDPIPER expert or contact your authorized SANDPIPER distributor with questions anytime.

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