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Level control
Float Switch for Water Pumps (3, 5 and 10 m Cable)
A float switch is a floating level sensor that starts or stops a pump, valve or alarm as the liquid rises and falls. Alden float switches come with 3 m, 5 m or 10 m cable for sumps, tanks, sewage pits and ponds across the UAE.
A float switch is a liquid level sensor made of a hollow floating body with a switch inside. It rises and falls with the water and opens or closes an electrical circuit, so it can start or stop a pump, operate a valve or trigger an alarm. Alden float switches come with 3 m, 5 m or 10 m cable.
Key features of the float switch
- Automatic level controlStarts and stops a pump without anyone at the tank.
- Simple and reliableA floating body with an internal reed switch has few moving parts.
- Three cable lengths3 m, 5 m and 10 m to suit sumps, tanks and plant rooms.
- Protects the pumpHelps prevent dry running and tank overflow.
- Works with many loadsPumps, valves, contactors and alarms.
- Low costA small part that prevents expensive pump failures.
A basement sump in a Dubai villa fills slowly after every shower on the roof terrace. Nobody checks it, and one night the water reaches the floor. A float switch changes that story. The float rises with the water, the switch closes, the pump starts, and the sump empties by itself without anyone noticing.
How does a float switch work?
A float switch moves up and down with the liquid level. Inside the hollow floating body is a switch, most commonly a reed switch with a magnet. A counterweight and a pre-set trigger point decide when the switch opens or closes as the level changes. When the switch is closed, current passes to the connected device, such as a pump.
The float is usually hung on its own cable. Where the cable is clamped sets the working range: the float swings and tilts between a low and a high position, switching at each end.
Models and specifications
| Product | Cable length | Technical data | Enquiry |
|---|---|---|---|
| Float switch 3 m cable | 3 m | Datasheet on request | |
| Float switch 5 m cable | 5 m | Datasheet on request | |
| Float switch 10 m cable | 10 m | Datasheet on request |
Electrical rating, cable type and materials are shown on the datasheet. Request a quote and mention the pump or load you want to control.
Applications and use cases
| Application | What the switch does | Typical setting |
|---|---|---|
| Sump and sewage pits | Starts the pump when the level rises | Basements, car parks, pump pits |
| Water tanks | Starts or stops transfer pumps at set levels | Potable water, rainwater, wastewater and sewage tanks |
| Refrigeration and air conditioning | Controls the water level | Condensate and cooling water sumps |
| Beverage industry | Controls filling or emptying of tanks | Process tanks |
| Industrial washers | Monitors the water level | Wash tanks and machines |
| Garden and pond pumps | Prevents dry running and floods | Terrace pits, planters, ponds |
Typical use cases: emptying a basement sump, controlling a roof tank filled by a transfer pump, stopping a pond pump before it runs dry, raising a high-level alarm in a drainage pit.
How does it help? Before and after
| Situation | Without a float switch | With a float switch |
|---|---|---|
| Sump fills up | Someone must notice and switch the pump on | Pump starts at the set level |
| Tank is empty | Pump runs dry and overheats | Pump stops before the inlet is exposed |
| Tank is full | Water overflows | Pump stops at the high level |
Float switch vs other level controls
Choose a float switch for simple, low-cost on/off control of pumps in tanks and pits. Choose a pressure kit for taps and boosters, and an electronic level sensor for exact or continuous level readings.
| Option | Suited to | Limits |
|---|---|---|
| Float switch | Tanks, sumps, pits, on/off control | Needs room to move freely; contact rating is limited |
| Vertical pressure kit | Starting a pump when a tap opens | Controls pressure, not tank level |
| Electrode or probe relay | Conductive clean water, fixed positions | Needs a relay panel and does not suit all liquids |
| Ultrasonic or pressure level sensor | Exact or continuous level readings | Higher cost and electronics |
How to choose and common mistakes
- Decide the job. Pump-down to empty a pit, or pump-up to fill a tank.
- Check the load. The pump’s current must be within the switch’s rating, or use a contactor.
- Pick the cable length. 3 m, 5 m or 10 m, enough to reach the control point without a joint.
- Check the liquid. Clean water, wastewater or sewage; confirm the material suits it.
- Check the space. The float must swing freely, clear of walls, pipes and the pump.
Common mistakes: letting the float catch on a pipe, running a large pump straight off the switch, setting the off level below the pump inlet, and leaving the cable tangled round the pump.
Installation and care tips
- Fix the cable with a clamp so the float swings freely.
- Keep the float away from the pump discharge, which can push it around.
- Set the off level above the pump inlet so the pump never runs dry.
- Never pull or hang anything by the float cable.
- Inspect the cable and clean the float regularly.
- Test it by raising and lowering the float by hand.
Safety and standards
Float switches carry mains voltage in wet places. Typical practice is to use a suitably rated protective device, keep joints out of the water and have a qualified electrician make the connections. Ask us for the electrical rating of the model before you connect a pump to it.
What to send for a quote
- What you want to control: pump, valve or alarm.
- Pump model, power and supply voltage.
- Tank or pit depth and the cable length you need.
- Liquid: clean water, wastewater or sewage.
- Quantity.
- Your location in the UAE.
Frequently asked questions
What is a float switch?
A level sensor that moves up and down with the liquid. It has a hollow floating body with a switch inside. As the level rises or falls, the float tilts or lifts and opens or closes the switch, which can start a pump, close a valve or sound an alarm.
How does a float switch work?
The most common design uses a reed switch with a magnet inside the float. A counterweight and a pre-set trigger decide at what level the switch opens or closes. When the switch closes, current passes to the connected device, such as a pump.
What cable lengths do you offer?
Alden float switches are offered with 3 m, 5 m and 10 m cable. Pick the length that reaches from the tank or sump to your control panel or pump with a little spare, so you do not need a joint in the cable.
Can I connect a float switch directly to a pump?
Only if the pump’s current is within the switch’s contact rating. For larger or three-phase pumps, wire the float switch to a contactor or control panel instead. Ask us for the rating of the model you choose before you connect it.
What is the difference between pump-up and pump-down use?
Pump-down empties a sump or pit: the pump starts when the float rises and stops when it falls. Pump-up fills a tank: the pump starts when the float drops and stops when it rises. The same float can do either, depending on how it is wired and set.
How do I set the on and off levels?
With a tethered float, the length of free cable between the float and the clamp sets the switching range. A longer free cable gives a wider gap between on and off levels. Set it so the pump stops before the water falls below the pump inlet.
Can it be used in sewage or dirty water?
Float switches are widely used in sump pits and sewage pits, as Alden’s product information notes. Keep the float free to move, away from walls, pipes and the pump flow, and clean it if grease or solids build up on the body.
Can I use it in a drinking water tank?
Float switches are used on tanks for potable water, rainwater, wastewater and sewage. For drinking water, ask us for the material details of the model and confirm it is acceptable for your tank and local rules.
Do I need a float switch with a submersible drainage pump?
It is strongly recommended. Without one, a pump must be started and stopped by hand, or it may run dry. A float gives automatic operation. See our drainage pumps and sewage cutter pumps.
Can a float switch control a valve or alarm?
Yes. It is a simple on/off signal, so it can operate a solenoid valve, an electric ball valve, a pump contactor or a high-level alarm. Use a relay if the load is above the switch’s contact rating.
What goes wrong with float switches?
The usual faults are a float stuck on a pipe or wall, a cable tangled around the pump, a build-up of grease or scale on the body, and water entering through a damaged cable. Check the float moves freely and inspect the cable regularly.
Do you supply float switches with pumps?
Yes. We supply float switches with our pond pumps and other Alden pumps, or on their own. Tell us the pump and we will quote the right switch.
Related guides
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