# Why Your Water Booster Pump Keeps Cycling | Guan Heng > A booster pump that cycles on and off usually means a faulty pressure switch, waterlogged tank or hidden leak. Here URL: https://plumberkotadamansara.my/guide/why-your-water-booster-pump-keeps-cycling/ Last-Modified: 2026-06-04 Guides # Why Your Water Booster Pump Keeps Cycling On and Off A booster pump that cycles on and off usually means a faulty pressure switch, waterlogged tank or hidden leak. Here's how to diagnose it. ![Home water booster pump and pressure tank](/images/featured/home-water-booster-pump-and-pressure-tank-mounted-.webp) ## What “cycling” actually means A booster pump that clicks on every minute or two, runs for a few seconds, then clicks off again is short-cycling. The cycle should normally last much longer — the pump runs, builds pressure, switches off, and the pressure tank slowly releases that pressure as taps are used. Only when pressure drops below a set point does the pump kick on again. When that cycle compresses to seconds instead of minutes, something is wrong. For water pump repair [/water-pump-services/ →](/water-pump-services/) , this is one of our most common call-outs. ## The three usual causes **A failing pressure switch.** The switch controls when the pump starts and stops. When it ages, the gap between its cut-in and cut-out points narrows, and the pump starts running on the smallest pressure drop. New switch, problem solved. ![Plumber checking a pump pressure switch](/images/content/plumber-checking-a-pump-pressure-switch-with-a-scr.webp) **A waterlogged pressure tank.** The pressure tank inside the system holds water and an air cushion. The air cushion is what releases pressure gradually as taps are used, so the pump can stay off. If the air bladder fails, the tank fills with water, the cushion is gone, and every tap turned on triggers an instant pump start. Re-pressurising or replacing the tank fixes it. **A small leak in the system.** Even a slow, invisible drip somewhere in the supply pipework lets pressure drop continuously. The pump keeps coming on to maintain it. This is often missed because there’s no visible water — only the pump cycling and a creeping water bill. ## Quick checks you can do safely Walk around the house with all taps closed. Listen for any drip, look at the meter (is it moving?), check under sinks and around the water heater for damp patches. If everything looks dry and the meter isn’t moving, the issue is almost certainly at the pump itself — switch or tank. If the meter is moving with taps off, there’s a leak somewhere in the system. That’s its own problem to trace. ## Why short-cycling matters even if it “still works” Some homeowners get used to the clicking and ignore it. The trouble is that every start-stop cycle wears the pump motor, the switch, and the seals faster than steady running. A pump short-cycling for months has often used up most of its life by the time it fails — and at that point, repair vs replace [/guide/repair-vs-replace-your-water-pump/ →](/guide/repair-vs-replace-your-water-pump/) gets closer to “replace.” Catching short-cycling early is usually a cheap switch replacement. Catching it after the motor has burnt out is a new pump. ## When to call us If the cycle is happening every few seconds and there’s no obvious external leak, give us a call. We arrive, test the switch and tank, check for hidden leaks, and recommend the fix — usually a switch replacement, a tank recharge, or finding the leak. ## Frequently asked questions Why does my water pump keep switching on and off? The most common cause is a failing pressure switch. Other possibilities are a waterlogged pressure tank that's lost its air cushion, or a small leak somewhere in the system letting pressure drop. Is short-cycling bad for the pump? Yes — frequent starts and stops wear out the motor and switch much faster than steady running. It's worth fixing early rather than letting it run that way for months. Can I fix a cycling pump myself? You can check for obvious external leaks. Pressure switch and tank issues need a plumber to diagnose and fix safely. ## Related guides ### Grundfos, Joven and Tsunami Pumps Compared Comparing Grundfos, Joven and Tsunami water booster pumps for Malaysian homes — strengths, typical use cases, reliability and parts availability. [Grundfos, Joven and Tsunami Pumps Compared →](/guide/grundfos-joven-and-tsunami-pumps-compared/) ### How to Size a Water Booster Pump for a Landed Home Choosing the right booster pump size depends on floors, outlets and target pressure. Learn the basics for landed homes in PJ and avoid oversizing. [How to Size a Water Booster Pump for a Landed Home →](/guide/how-to-size-a-water-booster-pump/) ### Low Water Pressure: High-Rise vs Landed Homes Why low water pressure differs between condos and landed homes in PJ — gravity tanks vs booster pumps, condo management rules, and how to fix each. [Low Water Pressure: High-Rise vs Landed Homes →](/guide/low-water-pressure-high-rise-vs-landed/) ### Repair vs Replace Your Water Pump Should you repair or replace an ageing water pump? Compare age, repair cost, recurring faults and efficiency gains to make the right call. [Repair vs Replace Your Water Pump →](/guide/repair-vs-replace-your-water-pump/) ## Need water pumps help in PJ? We're a local Saujana Damansara team covering Petaling Jaya and Selangor. Learn about water pumps [/water-pump-services/ →](/water-pump-services/) Call 012-219 8185 [tel:+60122198185 →](tel:+60122198185)