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    Causes of Reduced Flow in Boiler Circulating Feedwater Pumps and Solutions

    Publication Date:

    2026-01-18

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    The commonly used boiler circulating feed pump is a multistage type. Horizontal multistage centrifugal pump When the flow rate of the boiler circulating feedwater pump suddenly drops, stop just staring anxiously at the pressure gauge—this often signals a sharp increase in energy consumption and an imminent risk of shutdown. Zhonglian Pump Industry. 2025 The annual failure database shows that, 73% The flow anomaly stemmed from a preventable operational error, rather than the “natural aging” of the equipment. As frontline technical engineers, we’ve directly analyzed real-world cases: Last week, a chemical plant experienced a drop in flow rate... 20% It nearly brought the production line to a standstill—yet the root cause turned out to be an un-tightened valve. Today, we’re talking about boiler feedwater pump manufacturers. Changsha Zhonglian Pump Industry Summarize, based on engineering practice experience, the causes of reduced flow in boiler circulating feedwater pumps and their corresponding solutions—helping you quickly mitigate losses.

     

    Boiler feedwater pump

    Please click on the image to learn about Changsha Zoomlion Pump Industry. Boiler circulating feedwater pump 】Model Specifications and Product Details

     

     

    I. In-depth Analysis of the Core Causes Behind the Circulating Feedwater Pump Flow in Boiler Systems

    1. Impeller blockage and wear: Suspended particles in water (such as rust and silt) accumulate in the impeller passages, or prolonged operation leads to blade wear. According to... GB/T56572013 Standard: The impeller is worn excessively on one side. 1.5mm At that time, the flow attenuation reached 15%25% A case study from a thermal power plant: After cleaning the clogged impeller, the flow rate increased from... 85m ³ /h Restore to 110m ³ /h。

    2. Cavitation damage: Insufficient inlet pressure (e.g., water temperature > 85 ℃ or suction lift > 4m ) This causes the liquid to vaporize. When the bubbles collapse, they impact the surface of the impeller, not only reducing the flow rate but also producing a high-frequency abnormal noise. ASHRAE The guide confirms: Severe cavitation can cause a sudden drop in pump efficiency. 30% and shorten lifespan 50%。

    3. System sealing failure: Leakage at pipeline flange connections, aging of mechanical seals (commonly seen in operations exceeding... 2 A pump with 10,000 hours of operation, or an improperly opened bypass valve. Maintenance records from Zhonglian Pump Industry indicate that... 28% The flow problem stems from these “invisible leaks,” with the leakage rate at a single point potentially reaching as high as a certain percentage of the total flow. 10%。

    4. Motor and Drive Abnormalities: Frequency converter parameter drift or voltage fluctuations (e.g., ± 10% Above), resulting in a deviation of the rotational speed from the design value. Measured data: Rotational speed has decreased. 5% Traffic synchronization reduced. 4.8% (According to ISO5199 Centrifugal pump performance curve.

    5. Piping design defects: excessive number of elbows, abrupt changes in pipe diameter (e.g., DN150 Shrinks abruptly to DN100 ), increasing the resistance along the flow path. Before the renovation of a certain heating project, due to... 90 °Elbow super 8 One, system resistance increases. 22% Directly suppress traffic.

     

    II. Solutions for the Reduced Flow Rate of Circulating Feedwater Pumps in Boiler Systems

    Step 1: Rapid Screening

    After shutdown, visually inspect the impeller (by removing the pump cover) and use an endoscope to examine the flow passages. Simultaneously, test the inlet pressure (which must be ≥). 0.2MPa ) and water temperature (≤ 80 ℃). The Zhonglian Pump Industry’s free toolkit includes a simple inspection checklist (available for download on the official website). 10 Minute positioning 80% Frequently Asked Questions.

    Step 2: Targeted Repair

    Impeller issue: Excessive wear 1.5mm Must be replaced (recommended: Zhonglian high-chromium cast iron material for enhanced wear resistance). 40% ); For mild blockages, rinse with a high-pressure water gun; do not use hard objects to scrape.

    Cavitation Prevention: Install a pressure booster tank to increase the inlet pressure, or reduce the water temperature (e.g., by installing a heat exchanger). At one paper mill, this approach eliminated cavitation noise and restored flow rates. 25%。

    Leakage Treatment: Replace the fluororubber seal (temperature-resistant) 150 ℃), calibrate all valves to 100% Opening degree. For complex systems, it is recommended to use an ultrasonic leak detector.

    Step 3: Parameter Optimization

    Use a frequency converter to calibrate the motor speed to match the flow demand curve. For example, during the heating season when the load is low, the motor speed can be reduced to... 2800rpm (Original 2950rpm ), ensuring both high traffic and power efficiency. 8%。

    Step 4: Preventive Maintenance

    Flush the filter monthly (accuracy ≤ 100 mu m ), inspect pipeline supports for vibration resistance every quarter and perform dynamic balancing tests annually. The Zhonglian intelligent monitoring system can provide real-time alerts for flow fluctuations (deviation > 5% Automatic alarm.

    Step 5: Professional Intervention

    If self-diagnosis proves ineffective, immediately contact the certification engineer. Zhonglian Pump Industry. 48 Hourly emergency response, 2025 The average annual repair time has been shortened to 6 Hours—avoiding losses from a single outage exceeding... 10 Ten thousand yuan.

     

    The root cause of flow problems is systemic, not a failure of any single component. Regular maintenance is not a cost—it’s an investment. Customer data from Zhonglian Pump Industry proves that pump units undergoing standardized maintenance experience a lower annual failure rate. 65% Energy consumption reduced 12% Click on “Boiler Pump Maintenance Center” on our official website to get customized solutions and free diagnostic tools. Safe and efficient operation starts with a single, precise inspection.

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