Your Pressure Pump Keeps Clicking On: What to Check First

The taps are closed, yet the pump beside a home in Postmasburg keeps starting. In another illustrative scenario, a small workshop notices fluctuating pressure every time somebody washes their hands. Both situations deserve diagnosis before a replacement pump is ordered.

Describe the pattern

Our recommended starting point is a short fault record. Note whether the pump cycles with all outlets closed, only during low demand, or when several taps run together. Record any displayed alarm exactly. A brief video of the sound and controller display can help explain the symptom without dismantling equipment.

Grundfos identifies small leaks as one possible cause of frequent starts and stops. Its troubleshooting instructions also identify tank precharge, tank capacity, diaphragm faults, non-return valves, control settings and supply conditions as possible contributors. These are diagnostic possibilities, not a remote diagnosis of your particular pump. [1] [2]

Look for visible clues

• Check for dripping taps, running toilet cisterns and visibly leaking connections.
• Note the storage-tank level and whether the problem occurs only when the tank is low.
• Photograph the pump and controller model plates without opening electrical equipment.
• Tell the technician about recent filter changes, plumbing alterations or settings changes.

Keep observations separate from conclusions. “The pressure drops after taps close” is more useful than “the motor is finished”. It gives the technician something concrete to test.

Ask for measurements, not a pressure guess

Request checks of the actual start/stop behaviour, system pressure, non-return valve and pressure vessel, where fitted. The applicable manufacturer’s instructions should determine settings and limits. Grundfos’s instructions specifically link pressure-switch settings to the pressure tank’s permissible operating pressure. [2]

Our recommendation is to leave electrical fault finding, pressure-vessel adjustments and protective-device settings to a competent technician. Ask for the cause, corrective action and operating test to be written on the job sheet.

Prove the repair under ordinary use

At handover, ask the technician to demonstrate operation with all taps closed, at low demand, and with the usual simultaneous outlets. Discuss whether the problem has been corrected at its source and what maintenance the owner should schedule.

References and further reading

• [1] Grundfos: Frequent Pump Starting and Stopping
• [2] Grundfos: Installation and Operating Instructions — Troubleshooting

Cover photograph: Adam Šumník / Pexels. Illustrative stock image, not a Water Nest project. Image licence.