A common issue with Ebara self-priming pumps is failure to prime or the pump losing prime during operation. This can lead to reduced performance or pump downtime if not resolved quickly. Below are potential causes and troubleshooting steps to resolve the issue:
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Possible Causes of Pump Failing to Prime or Losing Prime

1. Air Leaks in the Suction Line
   • Cause: Air entering the suction line, around the pump seals, or at the pump connections can prevent proper priming by disrupting the flow of liquid into the pump.
   • Effect: When air is introduced into the system, the pump can lose prime and fail to properly start or continue operation.

1. Insufficient Fluid in the Pump Casing at Startup

1. • Cause: If the pump casing is not filled with liquid at the start, it can lead to the pump failing to prime.
   • Effect: A dry pump casing means the pump cannot create the necessary vacuum to draw in fluid, preventing the priming process from starting.

1. Clogged or Blocked Inlet or Impeller

1. • Cause: A blockage in the pump’s inlet or impeller, caused by debris or solids, can impede the flow of fluid into the pump.
   • Effect: Restricted flow prevents the pump from reaching prime and can lead to cavitation or air locks, which cause the pump to lose prime.

1. Improperly Sized Suction Line or Pipes

1. • Cause: An oversized or undersized suction line or excessive pipe lengths can impact the suction head and lead to prime loss.
   • Effect: This reduces the pump’s efficiency and ability to handle fluid, preventing it from reaching or maintaining prime.

1. Damaged or Worn Seals and Gaskets

1. • Cause: Worn or damaged seals and gaskets around the pump can cause air to leak into the system.
   • Effect: Air leakage can disrupt the self-priming process, preventing the pump from achieving and maintaining prime.

1. Inadequate Suction Head or Excessive Lift

1. • Cause: The suction head or vertical lift could be too high for the pump to overcome.
   • Effect: The pump may not be able to pull fluid from the source, leading to difficulty in priming or a complete loss of prime.

1. Low Fluid Levels or Inadequate Reservoir

1. • Cause: If the fluid source has dropped below the pump’s inlet or is insufficiently supplied, the pump may fail to prime.
   • Effect: The pump may suck air instead of fluid, causing loss of prime.

Troubleshooting Steps

1. Check for Air Leaks
   • Action: Inspect all suction line connections, joints, and seals for any visible leaks. Even small air leaks can prevent the pump from priming correctly.
   • Solution: Tighten or replace any loose fittings, seals, or gaskets. If air leakage is found around the pump’s shaft or casing, check and replace the shaft seal or gasket.

1. Ensure the Pump Casing is Filled with Fluid

1. • Action: Before starting the pump, ensure the pump casing is filled with fluid to enable proper priming.
   • Solution: Manually fill the pump casing with water (or the fluid being pumped) to prime it initially. Check the system to ensure no air is trapped inside the pump casing.

1. Clear Blockages from the Inlet or Impeller

1. • Action: Inspect the pump’s inlet, suction line, and impeller for any blockages or debris that may obstruct the flow of liquid.
   • Solution: Remove any debris, scale, or solids from the inlet and impeller. Clean the suction line and ensure nothing is blocking the fluid flow.

1. Verify Suction Line Size and Pipe Length

1. • Action: Check the size of the suction pipe and ensure that it is appropriate for the pump. Also, ensure that the suction pipe length is within recommended limits.
   • Solution: If the suction pipe is too long or too narrow, replace it with one of the correct size or reduce its length to improve the suction efficiency. Ensure that the suction head does not exceed the maximum recommended limits for the pump.

1. Inspect and Replace Worn Seals and Gaskets

1. • Action: Check for worn or damaged seals and gaskets on the pump casing, suction line, and around the pump shaft.
   • Solution: Replace any damaged or worn seals and gaskets to prevent air from leaking into the pump system. Ensure all seals are seated properly to avoid leakage.

1. Reduce Suction Head or Lift

1. • Action: Ensure that the pump is not lifting the fluid from too great a height, as excessive suction head can prevent the pump from priming.
   • Solution: Reduce the vertical lift by lowering the suction line or moving the pump closer to the fluid source to ensure sufficient suction pressure. Ensure that the system is designed with an appropriate lift for the specific pump model.

1. Check Fluid Level and Reservoir

1. • Action: Ensure that the fluid reservoir is sufficiently full and that the fluid source has not run dry.
   • Solution: Refill the fluid reservoir or source if necessary, and check that the fluid level is above the pump’s intake. Make sure the pump is not attempting to pull fluid from an empty or nearly empty source.

1. Verify Pump Orientation

1. • Action: Check that the pump is installed with the correct orientation. Improper alignment can interfere with the self-priming process.
   • Solution: Ensure the pump is mounted correctly and that the inlet and outlet ports are positioned for optimal flow.

Preventative Measures to Avoid Future Issues

• Regular Maintenance: Perform routine checks and maintenance on the pump, including inspecting seals, gaskets, and suction lines for damage or wear. Clean the inlet and impeller regularly to prevent debris buildup.
• Monitor Fluid Levels: Ensure that fluid levels are maintained in the system and that the pump casing is always filled with fluid to avoid dry running.
• Proper System Design: Ensure that the pump system is correctly sized and that the suction head, piping, and components are suitable for the application. This will help prevent prime loss due to improper system setup.

When an Ebara self-priming pump fails to prime or loses its prime, addressing the issue promptly can prevent further damage and ensure reliable pump operation. By carefully inspecting for air leaks, ensuring sufficient fluid in the pump casing, clearing blockages, and checking for proper installation and pump settings, you can easily resolve most prime loss issues. Regular maintenance and attention to system design will also help ensure long-term, trouble-free performance. For more info contact Ebara Suppliers or call us at +971 4 2522966.