Pump knowledge

Pump Not Delivering Water or Failing to Suction? Check These Points First

The pump is clearly running, yet no water comes out of the outlet, or the flow comes in spurts and quickly stops. This is one of the most common faults in use. Many people's first reaction is that the pump is broken, but in most cases the problem lies in priming and the suction line. Even for a self-priming pump, if the pump chamber and suction pipe are full of air on first use or after a long period of inactivity, it will struggle to draw water. Check in the order below; often you can find the cause without dismantling the pump. If during the check you smell burning, see smoke or notice signs of electric leakage, cut the power and stop the pump immediately. Do not keep energizing it to test, and never dismantle or inspect it while it is live.

burks self-priming pump

1. First check whether the pump is fully primed

An ordinary centrifugal pump cannot expel air by itself. Before starting, the pump chamber and suction pipe must be filled with priming water so that the impeller can throw the water out and create a vacuum to draw water in from the source. If priming is insufficient, the pump will run dry for a long time with a hollow sound and simply deliver no water. The remedy is simple: stop the pump, open the priming port and top up with priming water, expel the air from the pump, close the priming port and restart. After starting, wait a few minutes to see whether water flows normally. A self-priming pump must also be primed before first use; do not assume it will draw water as soon as it is installed and powered on.

2. Then check the suction pipe for air leaks and trapped air

Another frequent cause of failure to suction is an air leak on the suction side: loose pipe joints, aged gaskets or small cracks in a hose mean the pump draws a mixture of water and air, no vacuum can form, and water naturally cannot rise. During the check, inspect each suction pipe connection for intact sealing and the pipe for obvious damage. Keep the pipe route as free as possible of unnecessary bends and rises and falls to avoid trapped air. Sealing joints is external work on the pipework that you can do yourself, but do not dismantle the inside of the pump to look for leaks.

3. Do not overlook valves, foot valves and strainers

If the outlet valve is not open or the inlet valve is closed, the pump will never deliver water no matter how long it runs. This kind of basic cause is not rare on site, so first confirm that both the inlet and outlet valves are open. Then check the suction end: if the foot valve is jammed by debris and does not close tightly, the priming water leaks back to the water source after shutdown and the pump must be primed again next time; if the suction strainer is clogged with mud, sand or weeds, the inflow cannot keep up, which shows up as low flow or failure to suction. The strainer can be removed and cleaned after stopping and de-energizing the pump. If the foot valve and the inside of the pipework need to be cleaned and this requires dismantling, have it handled by a professional.

4. Also check the water source level and suction lift

If the water source level drops too much and the lower end of the suction pipe comes out of the water, the pump draws only air; if the suction lift exceeds the range allowed for this pump, it will likewise fail to suction. During the check, first confirm that the suction pipe inlet is actually submerged and that there is enough water in the source, then compare the actual suction lift and installation height with the manual. Do not install the pump too far from the water surface. Running dry for long periods damages the seals and the motor, so when you are sure there is no water, do not repeatedly test by running the pump dry for long periods.

5. What if all the above is normal and it still delivers no water?

If you have checked priming, pipe sealing, valves, strainers and water level and it still delivers no water, the problem may lie in a blocked or worn impeller or the motor rotation direction, which is beyond what can be handled without dismantling the pump. In particular, if you suspect the rotation direction of three-phase equipment is wrong, changing the wiring is electrical work: always have a professional electrician or after-sales service handle it, and do not rewire or dismantle the pump yourself. Write down the symptoms you found during the check—whether the pump was primed, whether the pipework leaks air, whether there is no water at all or the flow is intermittent—as this will save a lot of time when you communicate with us. If you still cannot determine the cause after checking, contact us through the contact details on the website pages or the online customer service, and send us the pump type, installation method and fault symptoms so that we can help you work out the direction of troubleshooting.

For more models for household boosting and everyday water supply, take a look at burks' self-priming pump product page and select a model to match your installation conditions.