Which setup suits your pump?

Your pump needs a way to start and stop when water is required. A pressure tank stores some water under pressure, while a switch or controller manages the pump.

Depending on your system, you may use a pressure tank with a pressure switch, an automatic controller, or a compatible combination of both.

What does a pressure tank do?

A pressure tank contains an air cushion separated from the water by a bladder or diaphragm.

As you use water, the tank supplies some of it before the pump needs to start. The amount available depends on the tank’s size, air charge and operating pressures.

A correctly sized and adjusted tank can:

• Reduce frequent pump starts during small or intermittent water use.
• Reduce wear associated with repeated starting and stopping.
• Help cushion pressure changes in the system.

A pressure tank does not fix leaks or guarantee protection against water hammer. Persistent cycling or banging pipes need investigation.

How does a pressure switch work?

A conventional pressure switch starts the pump when pressure falls to its cut-in setting and stops it when pressure reaches its cut-out setting.

This arrangement normally works with a suitably sized pressure tank. Pressure rises and falls between those settings during use.

A basic pressure switch does not necessarily include dry-run protection—this may need to be provided separately.

What does an automatic controller do?

A typical electronic controller starts the pump when demand causes pressure to fall, then keeps it running while water is flowing. It stops the pump when demand ends.

Depending on the model, features may include:

• Dry-run protection.
• Adjustable starting pressure.
• Automatic restart functions.
• Status lights or fault indicators.

These controllers are compact and convenient for many household installations. However, a basic on/off controller does not actively maintain a fixed pressure as demand changes.

What about constant pressure?

A variable-speed controller adjusts pump speed to help maintain a set pressure as water demand changes, within the pump’s capacity.

This is different from a basic automatic on/off controller. If consistent pressure is a priority, ask us which pump and control options suit your system.

Can you use a tank and controller together?

Often, yes—provided the controller supports it and the system is set up correctly.

A compatible pressure tank can reduce starts caused by small water draws. Tank sizing, positioning and air charge must suit the particular controller, so follow the manufacturer’s instructions.

Which option should you choose?

The best setup depends on your pump, water demand, pipework, elevation and the way you use water.

A tank-and-switch system may suit customers wanting fewer starts during intermittent use. An automatic controller may offer a compact solution with built-in protection. A variable-speed system may suit customers wanting more consistent pressure.

Elevation alone does not determine which control type you need.

Maintenance and electrical protection

Pressure tanks need periodic air-charge checks according to the manufacturer’s instructions. The correct setting depends on the control system; it should not be guessed.

Frequent cycling can indicate a lost air charge, a damaged bladder, incorrect settings or a leak.

An RCD and surge protection serve different purposes. Ask your electrician about suitable surge protection for your pump and electronic controls.

Need help deciding?

Tell us your pump model, water source and how your system is used. Photos of the existing installation are helpful too.

Call 09 294 7555 or email sales@pumpandpurify.co.nz, and we’ll help you choose a suitable setup.

Great water. Sorted.