Pump, Don't Dump: Diagnosing And Repairing Low Pressure Problems With Submersible Well Pumps

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A well is only ever as useful as the pump you use to draw water from it, and for many well owners and operators choosing a submersible pump makes a lot of sense. The watertight seal of a submersible pump that protect the motor and other vital moving parts also serve to extend the lifespan of the pump, and protect it from outside contaminants and exposure damage. 

However, submersible well pumps are not invincible, and it's a fair bet that your pump will experience problems at some point in its long working life. If your pump is delivering little more than a pathetic dribble of water, it is not generating enough pressure. This can be caused by a number of faults: 

• Blockages: Accumulation of sediment, sand or other contaminants inside the pipe can cause serious water pressure loss, and can damage the pump itself if left untreated. Check the pump's intake to look for blockages (intakes should be fitted with screens to prevent entry of large debris)—if none are found, you may have to disassemble the pump to check inside the impeller chamber. 
• Air locks: If a large air bubble forms within the pump or hoses it may cause diminished water flow. Attempt to flush it out with repeated bursts of high pressure water flow, but do not preserve with this for too long, as a solid blockage can cause serious damage. If your pump suffers from frequent air locks, have it inspected for possible leaks.
• Wear and tear: Older submersible pumps may simply be losing pressure due to the ravages of time, and pumps with worn impellers, impeller shafts or motors will become less efficient over time. If you feel confident enough to recognise a worn pump component when you see one, you can replace them yourself, but expert advice should be sought by less experienced pump operators. If several parts have become badly worn, replacement may be necessary.
• Loosened motor shaft: The constant, rapid rotation of a motor shaft in motion can cause the shaft to work itself loose over time, decreasing motor efficiency. Tightening or replacing the shaft can fix the problem, but you should seek professional aid when it comes to disassembling a complex pump motor. If your pump is suffering from a loose motor shaft, it may generate a characteristic knocking sound, but this may also be caused by the next possible problem:
• Cavitation: If air is leaking into your pump at a point before water reaches the impeller, the unwanted air can create air bubbles within the impeller chamber. This can cause serious damage, as well as a nasty knocking or grinding sound, and will cause rapid corrosion of the impeller blade. Cavitating pumps should be inspected for leaks and repaired immediately.

Attempting to diagnose the source of your pump problem before repairs begin is all-important—attempting to repair a complicated problem yourself can leave a pump damaged or inoperable, while calling in professional pump repairmen for a simple clog or switch problem can be unnecessarily expensive.

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31 May 2016