Why a level switch matters on a dosing pump
Short answer: A level switch stops the pump automatically when the tank runs empty. It costs only ₹1,050, but it protects two things — the pump diaphragm, which is damaged by running dry, and more importantly your membrane, which suffers when the plant runs without antiscalant.
What happens without one
We have seen this sequence many times:
- The antiscalant tank runs empty — nobody notices
- The pump keeps running but only draws air (dry running)
- The plant continues running without antiscalant — and nobody knows
- Two to four weeks later: scale forms on the membrane, permeate flow starts falling
- Two to three months later: the membrane has to be replaced
How it works
A float hangs in the tank. As the chemical level drops the float falls and breaks the circuit, stopping the pump. When the tank is refilled the float rises and the pump restarts.
Some versions also provide an alarm or panel signal, such as the relay output with level switch (₹2,625), which lights an indication on the control panel when the tank is empty.
Which one to choose
| Type | For which pump | Price |
|---|---|---|
| Regular level switch | PP (standard) pumps | ₹1,050 |
| Teflon wire level switch | PVDF pumps (acid) | ₹1,312 |
| Relay output plus level switch | Where panel indication is needed | ₹2,625 |
| Level switch for MAX 25/40 | MAX motorised pumps | ₹1,575 |
Separate switch or the PRO model
There are two routes:
| Route | Total cost | Better when |
|---|---|---|
| NEO 10 LPH plus switch | ₹8,085 | Budget matters, normal plant |
| NEO PRO 10 LPH | ₹15,750 | Heavy duty, industrial build needed |
For most customers the first route is sufficient — the switch does the same job and saves over ₹7,000.
Three points when fitting
- Set the float height correctly — low enough that the tank is nearly empty, but not so low that air enters the suction. Around 10 to 15 percent of tank height is typical.
- Keep the float clear of the tank wall — a float touching the wall can jam.
- Protect the wiring from chemical — the cable should run outside the tank, not submerged.
What else to do alongside
A level switch protects the pump when the tank empties, but it does not tell you whether chemical is actually reaching the water. For that:
- Mark the tank — a glance tells you whether the level is dropping daily
- Watch permeate flow on the rotameter — a falling flow is the first warning
- Watch permeate TDS on a TDS meter — rising TDS indicates membrane deterioration
Together these three tell you about almost any problem in good time.
Add a level switch
Send your pump model and the chemical — we will supply the correct type of level switch, from ₹1,050.
💬 WhatsApp par poochhein 📞 9910646957Frequently asked questions
What does a level switch do on a dosing pump?
It is a float suspended in the tank that stops the pump automatically when the chemical runs out. This prevents the pump from running dry and damaging its diaphragm, and it also tells you that the tank needs refilling.
What does a level switch cost?
Around one thousand rupees for standard pumps. The Teflon wire version for PVDF or acid pumps costs a little more, and a relay output version is available if panel indication is required.
Can I manage without a level switch?
Only if somebody checks the tank level every day. In practice people forget, and the plant then runs without antiscalant, which allows scale to form on the membrane. A replacement membrane costs many times more than the switch.
At what height should the float be set?
Low enough that the pump stops when the tank is nearly empty, but not so low that air can enter the suction line. Around ten to fifteen percent of tank height is typical. Keep the float clear of the tank wall so it cannot jam.
Which level switch is needed for acid dosing?
The Teflon wire version, because a standard wire degrades in acid. It costs only slightly more, and using the wrong one means the switch will fail quickly, so this is not worth economising on.