Water Pump Problems and How to Fix Them
- Runs, no water: prime and suction leaks
- Cycles on and off: pressure tank or switch
- Will not stop: leaks or switch setting
- Hums, no start: capacitor or jammed impeller
On this page
Pump Fault Finder
| Problem | Common causes | What to check |
|---|---|---|
| Runs but no water | Lost prime, air leak on suction, low water level, blocked foot valve | Re-prime; tighten suction joints; check the foot valve and water level |
| Switches on and off quickly | Pressure tank lost its air charge or is waterlogged; faulty switch | Check tank pre-charge; replace a burst diaphragm; test the switch |
| Will not stop | Leaking tap or pipe; switch cut-out set above what the pump can reach | Look for leaks; reset the switch with a technician |
| Hums but will not start | Failed start capacitor; jammed impeller; low voltage | Have the capacitor and voltage tested |
| Trips the breaker | Wiring fault, water in the motor, seized bearings | Call an electrician; do not keep resetting |
| Low pressure | Clogged filter or impeller, wrong pump size | Clean filters; compare the pump curve with your need |
Never Run a Pump Dry
Running without water burns seals and impellers. Fit dry-run protection with a controller or float switch: float switches.
Pressure Switches, Controllers and Tanks
Pressure SwitchKSh 4,500
MONDIAL PUMP CONTROLLERKSh 8,500
DAYLIFF BRIO PUMP CONTOLLERKSh 18,530
PEDROLLO EASY PRESS PUMP CONTROLLERKSh 24,000
DAVEY TORRIUM II PUMP CONTROLLERKSh 29,000
820 frp pressure vesselKSh 14,000| Product | Price |
|---|---|
| Pressure Switch | KSh 4,500 |
| MONDIAL PUMP CONTROLLER | KSh 8,500 |
| DAYLIFF BRIO PUMP CONTOLLER | KSh 18,530 |
| PEDROLLO EASY PRESS PUMP CONTROLLER | KSh 24,000 |
| DAVEY TORRIUM II PUMP CONTROLLER | KSh 29,000 |
| 820 frp pressure vessel | KSh 14,000 |
Current listed prices incl. VAT (updated 4 October 2026).
A controller starts the pump when a tap opens and stops it when flow stops, with built-in dry-run protection. A pressure tank stores some water under pressure so the pump does not start for every glass. See booster pumps and pressure tanks.
Repair or Replace?
Seals, capacitors and switches are cheap to replace. A burnt motor may be rewound (rewinding vs replacing); an undersized pump should be replaced with the right one: how to choose a pump.
Frequently asked questions
Why is my pump running but not pumping water?
Usually lost prime, an air leak on the suction side, a low water level or a blocked foot valve.
Why does my water pump keep turning on and off?
Most often the pressure tank has lost its air charge or is waterlogged, or the pressure switch is faulty.
Why won't my pump stop running?
A leak in the system, or a pressure switch set higher than the pump can reach.
Why does my pump hum but not start?
A failed start capacitor, a jammed impeller or low voltage.