Aquatec

A demand pump runs when the trigger opens and stops when it closes. That simplicity is why they are fitted to so many portables and sprayers — there is very little to go wrong, and what does go wrong is usually the switch rather than the pump.

They are also the component most often replaced unnecessarily. Before condemning one, check the strainer, the switch and the supply.

The range covers the Aquatec 12 V 170 psi demand pump, the 230 V 120 psi and 230 V 220 psi demand pumps, and the 220 psi pressure switch for the DDP5800.

How to choose

Voltage first, and it is not adaptable. A 12 V pump runs from a battery or vehicle supply; 230 V runs from mains. Fitting the wrong one is not a wiring adjustment.

Match pressure to the machine, not to ambition. A 220 psi pump on a machine plumbed and valved for 120 psi will find the weakest fitting in the line.

Cycling at the trigger is correct behaviour. A demand pump switching on and off as the operator works is doing exactly what it should. Rapid short-cycling with no flow is the pressure switch or an air issue, not a failed pump.

The switch is a separate part and a cheaper fix. A pump that will not shut off, or will not start, is very often the pressure switch. Test it before ordering a pump.

Related: Pumps & Motors, Pump Repair Kits & Seals, Portable Parts and Sprayers.