Surface Pumps

The limit worth knowing before you choose

A surface pump draws water up; it does not push it from below. Suction lift is capped by atmospheric pressure — about 8 metres in practice, and less at altitude or with a long suction run. If the water sits deeper than that, the answer is not a more powerful surface pump but a submersible one.

Beyond that physical limit, what decides real-world performance is total head: static lift, the pressure you want at the outlet, pipe run, bends and bore. A flow figure quoted without those numbers tells you nothing.

Three types, three jobs

• Self-priming centrifugal: will draw even when the suction line is not completely full. The usual choice for wells and pillow tanks.
• Multistage: high pressure with steady flow. Suited to long irrigation runs or several sprinklers at once.
• Automatic: built-in pressure switch starts and stops the pump on demand. Convenient for WC supply or a domestic booster set.

Technical specification

Typical applications

• Pillow tanks: filling, emptying and transfer between tanks. See the compatible pillow tanks.
• Wells and boreholes: abstraction down to roughly 8 m of water depth.
• Irrigation: feeding sprinklers, drip lines or a reel, sized on the flow and pressure you actually need.

Installation: the four points that prevent a callout

• Site the pump somewhere dry and sheltered, as close to water level as you reasonably can.
• The suction line must be airtight and rise gently towards the pump, with no high point where air can collect.
• Fit a foot valve with strainer at the end of the suction line — without one the pump loses its prime every time it stops.
• Fit union connectors either side of the pump so it can be removed without cutting into the pipework.

Maintenance and fault-finding

• Check joints for tightness and clean the suction strainer periodically.
• Pump will not prime: almost always air entering the suction side. Check seals, unions and that the pump body is filled.
• Pump cycles on and off constantly: check the pressure switch and the pre-charge pressure of the expansion vessel.
• Poor flow: inspect the foot valve, the strainer and the pipe bore before blaming the pump.

Recommended accessories

• Complete suction kit: strainer, foot valve and hose
• Pressure switch for automatic operation
• Inlet filter to protect the pump from debris
• Unions and adaptors to suit the installation

Request pump sizing