Pump troubleshooting
Why does my pump keep turning on and off?
If your pump clicks on and off every few seconds, even when no one is using water, that’s called short cycling. It’s worth sorting early: the constant starting and stopping wears the motor and switch far faster than steady running does. The good news is the causes are few, and easy to narrow down.
Every start loads the motor and the switch. A pump that cycles all day wears out far sooner than one that runs steadily.
What short cycling actually is
A pressure pump is meant to start, run for a bit, and stop, holding pressure in between. Short cycling is when it starts and stops rapidly in a short window. The pump is reacting to pressure that keeps dropping away faster than it should.
Most pumps work with a small pressure tank: a steel tank beside the pump, or a little one built in. Inside, a rubber bladder keeps water on one side and pressurised air on the other, and the air acts like a spring, pushing out stored water so the pump does not have to start for every glass. Over time that air slowly escapes. Once the tank is full of water and the spring is gone (plumbers call this waterlogged), the pump starts for every drop you use. This is the pressure tank, not your rainwater tank.
The usual causes
| Cause | How you can tell | What to do |
|---|---|---|
| Pressure tank has lost its air | Tap the tank: it sounds solid all the way up instead of hollow at the top. | Re-pressurise the air side |
| A slow leak | The pump cycles with every tap closed, and the water meter creeps overnight. | Check toilets, taps, outdoor fittings and garden lines. |
| Worn or misadjusted pressure switch | The tank has its air and there are no leaks, but it still cycles. | Have a pump technician or electrician adjust or replace it. The switch carries mains power. |
| Leaking non-return or foot valve | Pressure drops quickly after the pump stops, and it may lose prime. | Check the valve |
What to check
- Turn everything off and watch. If it still cycles with no taps open, water is escaping somewhere or the pressure tank has lost its air.
- Check the pressure tank. Tap the side: a healthy tank sounds hollow up top and solid at the bottom. If it’s solid all over, the air has gone. Many tanks can be re-pressurised at the air valve (like a tyre) to the maker’s spec; some need replacing.
- Look for leaks: a dripping tap, a running toilet cistern, a weeping fitting, or a garden line left cracked open.
- If the tank is healthy and there are no leaks, the pressure switch may be worn or set with too narrow a gap.
How a Grewa Boost pump helps
A Boost pump runs at variable speed and holds a steady setpoint instead of slamming on and off, so it doesn’t short cycle the way an old fixed-speed pump does. It also watches its own overnight behaviour: if it’s quietly nudging back on when nothing should be running, Grewa flags the signature of a slow leak in the app, so you can find the drip before it finds your water bill.
Common questions
Is short cycling bad for my pump?
Yes. Each start puts load on the motor and switch, so rapid cycling shortens their life. Fix it rather than live with it.
Can a leak really make the pump cycle?
Yes. Even a slow leak or a running toilet bleeds pressure away, so the pump keeps topping it back up. It’s one of the most common causes.