Float Switches Australia

A float switch is the cheapest piece of protection you can put on a pump. It senses the water level and tells the pump when to start and when to stop. Without one, a pump can run dry and burn out its seals and motor, or a tank can quietly overflow all night.

Pumptastic stocks cable-suspended float switches in 10m, 20m and 30m lead lengths, plus Matelec multi-float trees for pump stations that need several switching points on one bracket. Everything ships Australia-wide from our Western Australian warehouse, and our team can tell you which switch suits your pump before you order.

What a Float Switch Actually Does

Inside the sealed plastic body is a small microswitch and a weight. As the water level rises or falls, the float tilts. Once it passes roughly horizontal, the weight shifts and the microswitch flicks over, opening or closing the circuit that feeds the pump.

That simple action covers two opposite jobs:

• Pump down (emptying) - the pump runs while the water is high and switches off as the level drops. This is what you want in a sump, a pit or a sewage well.
• Pump up (filling) - the pump runs while the water is low and switches off once the tank is full. This is what you want when transferring into a header tank or storage tank.

On most cable-suspended float switches you swap between the two by turning the float 180 degrees. Always check the wiring diagram supplied with your switch before you commit.

Types of Float Switch We Stock

Cable-Suspended Float Switches

The most common style in Australia, and the one most people picture when they hear "float switch". A polypropylene float hangs on a length of flexible cable from a bracket, a cable weight or the pump's discharge pipe. The length of free cable between the anchor point and the float sets the switching range - more free cable means a bigger gap between the on and off levels.

Our 10m float switch, 20m float switch and 30m float switch all use the same design - only the cable length changes. Pick the length based on the distance from the water back to your control box or power point, not on the depth of the tank.

Multi-Level Float Trees

A pump station often needs more than one switching point: a stop level, a start level, a lag pump start and a high-level alarm. Rigging four separate floats on one riser is fiddly, and they tangle.

The Matelec Multi-Level Float Tree solves that by mounting the floats on a single moulded assembly at fixed spacings. Installation is faster, the levels stay where you set them, and the floats cannot wrap around each other. We stock three-float versions in 10m and 20m cable, and a four-float 20m version for stations that also need an alarm level. See the full Matelec range for matching control gear.

Pumps With a Float Switch Built In

If you are starting from scratch, an automatic pump may be simpler than a manual pump plus a separate switch. Several Davey pumps and models in our sump pump range ship with a float already fitted and wired.

Choosing the Right Cable Length

This is the question we get asked most, and the answer catches people out. The cable length on a float switch is about reach, not depth. You need enough cable to run from the float, up out of the tank or pit, and across to wherever the pump plugs in or the control box sits.

• 10m - domestic rainwater tanks, small sumps, and pits where the switchboard is close by.
• 20m - deeper pits, larger tanks, or where the control box is on a wall some distance from the tank.
• 30m - bores, deep wells, large in-ground stations, and rural sites with a long run back to the shed.

Measure the actual cable path before you order. Joining extra cable onto a float switch lead is not ideal in a wet pit, and running short means starting again.

What to Check Before You Buy

• Switching current - the float switch has to handle the pump's starting current, not just its running current. Larger pumps should switch through a contactor or a pump controller rather than directly off the float.
• Liquid type - clean rainwater, greywater and sewage are different environments. Check the float body and cable material suits what it is sitting in, especially where oils or chemicals are present.
• Free cable length - a short tether gives a narrow band between on and off, so the pump cycles more often. A longer tether gives a wider band and fewer starts. Frequent starting is hard on a motor.
• Room to swing - the float needs clear space to tilt without catching on the pump, the pipework or the wall of a narrow pit.
• Wiring - anything hard-wired at 240V is licensed electrical work in Australia. Piggyback-plug versions can be plugged in without an electrician, but the fixed wiring behind them still has to be compliant.

Where Float Switches Are Used

• Rainwater and storage tanks - stopping a transfer pump before it runs the tank dry.
• Sumps, basements and lift wells - clearing water automatically after rain.
• Sewage and greywater pump stations - usually with a float tree and a duty/standby controller.
• Bores and wells - protecting a submersible bore pump from dry running when the water table drops.
• High and low level alarms - a spare float wired to a siren or a building management system.
• Irrigation and stock troughs - keeping supply tanks topped up without anyone watching them.

Float Switches and the Rest of Your Control Gear

A float switch handles level. It does not handle pressure, phase failure or overload. Most installations pair it with other components:

• Level control components - probes, relays and alternators for more complex stations.
• Pressure control components - for pressure systems where level is only half the picture.
• Automation and control solutions - full control panels and duty/standby setups.
• Motor capacitors - the other part that fails when a pump has been short-cycling for months.

Frequently Asked Questions

How do I reverse a float switch from filling to emptying?

On most cable-suspended floats you rotate the float body 180 degrees so the switch operates on the opposite tilt. Some models instead use different cores in the cable for pump-up and pump-down. Check the diagram that comes with your switch - do not assume.

What cable length do I need?

Enough to reach from the float, out of the tank, and back to the pump's plug or control box. Measure the whole path. Cable length is about reach, not water depth.

Can I install a float switch myself?

A piggyback-plug float switch plugs into a standard outlet with the pump plugged into the back of it, so no electrician is needed for that connection. Anything hard-wired into a control box or switchboard is licensed electrical work in Australia and must be done by a qualified electrician.

Why is my pump switching on and off constantly?

Usually the free cable length is too short, so the on and off levels are only a few centimetres apart. Let out more cable between the tether point and the float to widen the gap. Also check the float is not catching on pipework partway through its swing.

Can one float switch control a large three-phase pump?

Not directly. The float should switch a contactor or controller, which then switches the pump. Running a large motor's full load through a float switch's internal microswitch will burn the contacts out. Call us if you are unsure what your pump needs.

Will a float switch work in sewage or dirty water?

Only if it is rated for it. Sewage and greywater applications need a float with a suitable body and cable sheath, mounted so solids and rags cannot foul it. The Matelec float trees are built for pump station duty.

How long does a float switch last?

There is no fixed figure - life depends on how many times it operates and what it sits in. A float in a rainwater tank that cycles a few times a day will outlast one in a busy sewage station by years. Because they are a wear item, many sites keep a spare on the shelf.

Do you deliver outside Western Australia?

Yes. We ship float switches Australia-wide, with free shipping on orders over $100.

Need Help Picking a Float Switch?

If you know your pump model and roughly how far the cable has to run, we can tell you which switch to order in a couple of minutes. Call (08) 6384 5884 or get in touch here. Pumptastic is based at 7 Hampton St, Greenfields WA 6210.