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please help to correct this

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chamilackjm

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this is water level control circuit , this circuit shows the water level as well as when water level is low relay is on and when water level is high relay become off, LED also indicate weather relay is on or off .... although the water level shows properly but always LED on, LED on means water pump is on , what is the problem with this
 
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hi,
The Manual override switch is not clearly shown.

I am assuming that the switch is shown in the Override position.??

also that the Override switch has 1,2,3 and 4,5,6 contacts.?
 
No this is normal , not override..

If its drawn as Normal, the LED will always be ON, as R15 is connected to 0 volts.

Look at this modification.

Also you should have a suppression diode across the relay coil.
 
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is it a signal diode?????

The diode across the relay could be a 1N4001 type or equivalent.

You say that the Override switch is in the Normal position on the drawing you posted.
This would mean that the relay/pump is always On and the sensing circuit would never control the relay.??

I would say that if the Override switch is in the Normal position the circuit would be in sensing control operation, not manual Override.

Look at this modified drawing.

Also the 10K base resistor to the BC547 will only give approximately 1mA, so with a saturation gain of the BC547 of say 20, thats only 20mA through the relay coil,, what is the resistance of the relay coil.?
 
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PWR Y1-1 appears to be tied to ground, is the tank grounded? If you have 4 levels, empty, low, half, full, you also need a common. How conductive is the water?
 
PWR Y1-1 appears to be tied to ground, is the tank grounded? If you have 4 levels, empty, low, half, full, you also need a common. How conductive is the water?

this moment it only shows 3 level, ground is the common one, when that three probes ground with the common it shows the level..
 
The diode across the relay could be a 1N4001 type or equivalent.

You say that the Override switch is in the Normal position on the drawing you posted.
This would mean that the relay/pump is always On and the sensing circuit would never control the relay.??

I would say that if the Override switch is in the Normal position the circuit would be in sensing control operation, not manual Override.

Look at this modified drawing.

Also the 10K base resistor to the BC547 will only give approximately 1mA, so with a saturation gain of the BC547 of say 20, thats only 20mA through the relay coil,, what is the resistance of the relay coil.?

it may 500ohms coil, i am using electric splinkler instead of relay, its a electrical water switch
 
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