A pump that turns on and off every few seconds is short cycling — the fastest way to destroy a well pump. Here are the causes and fixes in order.
Short cycling is when your well pump turns on and off repeatedly in rapid succession — sometimes every 2–10 seconds. Each motor start draws 3–5x normal running amperage, overheating the windings and wearing bearings at an accelerated rate. A pump that short cycles for weeks instead of months can fail in a fraction of its normal lifespan.
The bladder in your pressure tank has failed. The tank is completely full of water with no air cushion. Every drop of water used triggers the pump because there is no stored pressure to draw from.
Test: Press the Schrader valve with pump off and pressure at zero. Water = failed bladder. Replace the tank.
Even with an intact bladder, a tank with wrong pre-charge pressure delivers poor storage. Pre-charge must be 2 PSI below cut-in (28 PSI for 30/50, 38 PSI for 40/60). Check and adjust with a tire gauge.
A tank too small for your pump GPM stores insufficient water per cycle, causing rapid cycling even when functioning correctly. Use our calculator to verify your tank is properly sized for your pump.
Standard switches have a 20 PSI differential (30/50 or 40/60). A switch with less than 15 PSI between cut-in and cut-out will cycle more rapidly than normal. Replace with a standard differential switch.
⚡ Act fast. Short cycling kills pumps. If your pump is clicking on and off every few seconds, turn it off and diagnose the cause before running it further.
An undersized tank causes low pressure, short cycling, and early pump failure. Check yours free in 2 minutes.
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