Surface or Borehole Pump? Fix Lost Prime, Cycling or Low Pressure

Your pump sucks air and loses its prime, clicks on at night with every tap shut, or the shower barely trickles. Most of these faults come down to water depth, air in the suction side, a pressure tank that has lost its air, or weak mains pressure.

PartsForMachines stocks 28 water pumps and pump kits from Draper, SIP, Sealey, T-T Pumps and Clarke in its surface mounted and booster pumps range. They cover surface, booster, borehole, submersible, petrol and diesel units, plus inlet filters.

Water Too Deep? When a Surface Pump Will Not Do and You Need a Borehole Pump

If the water sits more than about 7 to 8 metres below the pump, you need a borehole pump. In practice a surface pump lifts water only about 7 or 8 metres up its suction pipe, less with long or narrow pipework.

Don’t confuse suction with head. A surface pump such as the WPS062S lifts from up to 8 metres down and has a 38-metre maximum head: the total height it can raise water, suction included. A borehole pump such as the WPW9355 sits under the water and pushes it up, with a 55-metre maximum head and a 22-metre cable.

Why Does My Surface Pump Keep Losing Its Prime?

Usually because air is getting into the suction side, or the water drains back between runs. Check every suction joint is airtight, not just watertight, and that the suction hose is no smaller than the pump inlet. A leaking foot valve lets the water drain back down the pipe, and a lift beyond the pump’s limit may stop it priming at all.

Then refill the casing and suction pipe through the priming plug and restart. A clogged strainer also starves the pump, so fit an inlet filter such as the WPF2 where the water is not clean.

Why Does My Pump Switch On and Off When No Tap Is Open?

Because pressure is leaking away, so the pressure switch restarts the pump. Check for a dripping tap, a toilet cistern that keeps filling or a weeping joint.

If it clicks on and off rapidly while a tap runs, the pressure tank has probably lost its air charge. With the pump switched off and the pressure drained, check the tank’s air valve with a tyre gauge. It should read about 2 psi below the pump’s start pressure. On a 20 to 40 psi switch, like the one on the 06907 booster pump with its 20-litre tank, that means about 18 psi.

Will a Booster Pump Fix Low Water Pressure?

It can, where the incoming pressure is the problem. Measure first: time how long a tap takes to fill a bucket, and check the pressure with a gauge.

A plug-in booster set such as the TT/AUTOSMART-M94 starts and stops automatically, has dry-run protection and stores water in a 24-litre tank. Connection rules vary by country. In England and Wales, for example, any pump taking over 12 litres a minute from a supply pipe needs the water company’s consent before you fit it.

What Should I Check Before I Buy?

• the depth to the water at its lowest: beyond the pump’s suction figure (often 6 to 8 metres), choose a borehole pump
• the height to your highest outlet, against the pump’s maximum head
• the water: clean, brackish or dirty, and the largest particle the pump takes
• the power: a 230V socket nearby, or a petrol or diesel pump where there is no mains
• controls and fittings: pressure switch and tank, dry-run protection, inlet size (1 inch on many pumps)

Browse the surface mounted and booster pumps range, or contact the PartsForMachines team by WhatsApp, telephone or email with your water depth and highest tap height.

Product options, delivery options and returns terms are shown on each product page. A 30-day return policy applies to eligible items.

Frequently Asked Questions

Is a 3-inch petrol or diesel pump worth it over a 2-inch?

For moving a lot of water, often yes. The 2-inch 03933 is rated at 550 litres a minute, while the 3-inch 04909 diesel pump manages 1,000, both with a 30-metre maximum head. The 04909 also handles dirty water with particles up to 6 mm.

Will I get the maximum flow shown for a pump?

Not usually. The maximum flow comes at little or no head, and flow falls as the height you pump to rises. Friction in long or narrow hose adds to that height, so allow a good margin when you compare pumps.

What is a foot valve and do I need one?

It is a one-way valve at the bottom of the suction pipe, fitted below the lowest water level. If it leaks, water runs back down the pipe between runs and the pump can lose its prime.

Should I prime the pump while it is running?

No. With the pump off, remove the priming plug, fill the casing and suction pipe with water, refit the plug, then start it. Even a self-priming pump needs this first fill: the CBT1400SS, for example, self-primes only after an initial priming.

Can a surface pump run dry?

Avoid it. Running without water can damage the seals, so stop the pump if no water comes through and check the prime. Some booster sets, such as the Hidro Boost AutoSmart, have dry-run protection built in.

Do I need an inlet filter on a surface pump?

Yes, if you draw from a pond, tank or water butt. Debris can clog a surface pump, cut its flow and shorten its life, and many surface pumps take particles of only 1 mm. Filters come in 1-litre (WPF1) and 2-litre (WPF2) sizes.

How often should I check the pressure tank’s air charge?

Check it periodically, and straight away if the pump starts cycling rapidly; one tank maker advises once a year. If water comes out of the air valve, the bladder has failed and the tank is waterlogged, so it needs replacing.

Can I use a surface pump to empty a flooded cellar?

A submersible dirty-water pump usually suits the job better. The SIP 06888, for example, sits in the water, passes particles up to 35 mm and has a float switch that stops it running dry.

What size hose should I use?

Use a suction hose no smaller than the pump inlet. Keep delivery runs short and wide enough too, because friction in the hose cuts flow. A clear-walled suction hose, like the one in the 92776 flood kit, lets you see the water moving.