Automatic Water Level Controller Circuit With Dry Run Protection | For Sump & Overhead Tank | Transistor Based

   Author: Manikandan K J  Circuit Sponsor:

Water level controller is necessary for many reasons. Water level can be monitored and controlled automatically without any human intervention. Thus, it saves water wastage, electricity and time. This can be used both in industries and houses. The circuit I am going to share in this post controls water level in the overhead tank or any tank. Can be used in tanks of any liquids (eg. oil) provided it should not be hot. The cost of making this circuit is very low and can be assembled on a general purpose board if you are using it for your personal use. For commercial purposes, you can buy one from here.

kjmindia Water Level Controller For Sump And OHT

Sump & OHT Water Level Controller board |

Working of the circuit:

This circuit is controlled by a single NPN transistor with the help of two cable float switches. It will constantly monitor both the levels of sump and overhead tank and protects the motor pump from dry run. The unregulated DC voltage from the transformer is regulated by the voltage regulator Ic. Choosing the best quality cable float switches is very important. Float switches consists of three terminals, but, here in this circuit, we are going to use only two terminals from both float switches. Black wire is labeled as C, blue wire is labeled as BLU and brown wire is labeled BRO. Overhead tank uses black and blue wire of the float switch and Sump uses black and brown wire of the float switch.Terminal blocks for input(INP) and output(OUT)  are optional because we can directly connect it to the terminals of the 40A relay.

Scenario 1:

When both tank and sump are empty,

Power LED and Yellow LED will be turned ON

Scenario 2:

When the tank is empty and sump is full,

Power LED and Motor on LED will be turned ON

Scenario 3:

When both the tank and sump are full,

Power LED and Full tank LED will be turned ON

Scenario 4:

When the tank is full and sump is empty,

Power LED , Full tank LED and Sump Dry LED will be turned ON

Over Head Tank Controller:

We can also use this circuit to control overhead tank alone by shorting the sump sensor connection.
In this case it will turn on the motor when the water level falls below the bottom and turns off automatically when the tank is full.


MCD Water Supply Controller

As MCD Water Supply Controller Circuit Board:
Municipal water supply controller circuit board.

Sump & OHT Cable Float Water Level Controller


-Cіtу Suррlу Line ореnѕ оnlу fоr 1 hour аnуtіmе during 6AM – 10AM оr rаrеlу ѕоmеtіmеѕ іn thе еvеnіng dереndіng on thе wаtеr guy.

– Wе nееd tо kеер a watch durіng these times аnd kеер thе main tар open tо ѕее if the wаtеr hаѕ соmе.

– Once thе water hаѕ come, wе hаvе tо turn оn thе wаtеr рumр аttасhеd to thе mаіn supply line tо рumр water іntо оur undеrgrоund water tank.

This рrосеѕѕ саn be automated bу uѕіng оur сіrсuіt board.
Apart frоm this bоаrd, we require thе fоllоwіng:
1)12V,500mA оr 1A transformer
2)Nоrmаllу closed vertical оr horizontal magnetic flоаt ѕwіtсh
3)SS flоw sensor(to bе fitted on thе іnlеt ріре)
4)Cаblе ( 2 соrе ). Lеngth as rеԛuіrеd

If the flow of water is intermittent in the initial stage, pump will start and stop as per the flow of water. In order to avoid this, we can add a timer. So that, once the pump is turned on after sensing the water, it will not get turned off until the water flow stops or the tank is full.

Circuit Diagram:

Automatic Water Level Controller Circuit With Dry Run Protection | For Sump & Overhead Tank | Transistor Based

Parts Required:

Transformer : 12V, 500mA
DB1 – Bridge Rectifier W10
Capacitor: C1 = 470uF, 50V
IC U1 = 7812
Resistor: (All 1/4W)
R1, R2,R3,R5 = 4.7K
R4 = 3.3K
2 Pin PCB Mount Terminal Connectors:
INP (optional)
OUT (optional)
D1,D2,D3 = IN4007
Q1 = 2N2222
RY1 = 12V,40A

Board 2 contains four LEDs of different colours.

Connection Diagram:

Sump & OHT Water Level Controller Connection Details |

Circuit Diagram Without Transistor:

coming soon…

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