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About 20 years ago, a friend of mine came to me saying that he had to repair a customer’s  water level control made out of electromechanical relays which was falling apart.  He understood that the original control relied on conductivity of water. The customer didn’t want any type of float switch so he had to stick to the way it was meant to work.

He could start the pump whenever water fell below the “low” level electrode and pump would stop once it reached the “high” level electrode but, as water was consumed and its level barely dropped just below “high”, his circuit would re-start the pump just to stop it as soon as “high” electrode was touched by water again. This process kept going on and on until he switched power off. His circuit was oscillating which was not good for a 5 HP water pump or any pump at all.

He needed help. At this point I asked him that instead of working with relays, wouldn’t it be nice if the control were electronic which would probably be less expensive, more reliable and have a longer life?

 I intended to build a kit for Club Jameco out of how I remembered this control worked and this is what this instructable is all about. 
 

*** Disclaimer: This kit is meant to operate with equipment such as line operated water pumps or motor starter relays and/or contactors at lower control voltages. Line voltage is dangerous and if mishandled can cause injury or death. If you are not familiar or have not worked with line operated equipment, have a licensed electrician do the power wiring for you. This kit is meant to be educational in nature and can be used with line operated equipment if National Electric Code guidelines are followed. ***
 

Step 1: Proposed Control Slide show

The slide show included in this instructable shows the basic operating theory behind this control. It assumes that the pump is a small plug-in pump. This control has a small 12V coil relay whose contacts are rated at 10A 120V. You can select any relay to suit your water pump's power source.

<p>hi sir can you share with me the eagle files? so that i will not have to make the whole schematic and just modify the existing one that you have ? </p><p>thank you <br></p>
<p>Hi:</p><p>Great project. We have some large (six feet high) poly tanks at the cottage we use to store water. Will the pobes work on tanks this large? What is the maximum distance between the probes?</p><p>Thanks</p><p>Jeff</p>
Hi there Bundolo,<br><br>Two years ago, one reader had a kit installed to control a 1,600 gal tank located under a deck (6.5' height). The tank was used for irrigation somewhere in Oregon.<br><br>I haven't tested what the maximum distance between high level electrode and ground could be. I guess that's something I'll test during this coming weekend.<br><br>Thanks for your comments Bundolo.<br><br>Rlarios<br>
Thanks Rlarios<br>we'll be trying out several approaches for monitoring the tanks this summer. We'll try your method, and also monitoring the tanks with a sensitive pressure sensor, and an ultrasonic method. Ultmately I want to be able to monitor them remotely, they're about 250m away from the cabin, so exploring methods of doing that as well. Should be a fun project. when I get it all put together I'll put it on Instrucables. Any suggestions welcome.<br>Jeff
hi, thx for the great toturial. I've redesigned the circuit and make it more compact. just removed the voltage regulation part and re order other parts. it's working now in my aquarium with titanium sensors. thx again.
Please sir send circuit diagram <br>prajapatianand7878@gmail.com
Anand7878,<br><br>Check step 3 of this instructable. Circuit schematic diagram is shown right there.<br><br>Rlarios<br>
Dear Anand7878,<br><br>Circuit diagram is shown in the instructable.<br><br>Or, do you mean something else? <br><br><br>Regards<br><br>rlarios
Great work HamedI2!<br><br>I will really appreciate if you could share a link about those titanium sensors.<br><br>Thanks, sir.
<p>hi i was wondering can this circuit be used in reverse? i need to turn on the pump when tank is full and stop the pump when a certain threshold is reached </p>
Hi there Tycss,<br><br>Yes, it can work in reverse. If you are in a hurry, check the instructions I gave to &quot;Murray&quot; about three years ago on how to modify the circuit to do what you just asked.<br><br>I said back then I would write about these simple changes in the instructable, and I never did. Shame on me. I hope I don't forget this time.<br><br>Cheers!
Please sir i want to make it please send me circuit diagram on my whatsapp or email<br>prajapatianand7878@gmail.com<br>Whatsapp:-+919737020883
<p>Hi rlarios, i want to say thank you for sharing this wander full instructable and I have a question, hope you can answer.</p><p>Can this circuit work in 5v? I have tons of 5v phone chargers, would be perfect for me :)</p>
Hi Mark 62726,<br><br>Thank you for your comments.<br><br>You can have the CD4001 operate off 5V. You would need a 5V coil relay with contacts rated at least at 1A at 120Vac, and instead of the rectifier diodes and 7812 voltage regulator, you could use your 5V phone charger.<br><br>rlarios<br>
<p>I want to make a printed PCB. So what can I do. I checked your cadsoft eagle file but it is doesn't seem to work on my cadsoft eagle so what can I do. Pls send me PCB design in PDF format so I can print it and itche it on PCB.</p>
<p>Hey, I made the water level controller , it worked alright when i tested it in buckets, but after installing it in underground and overhead tanks, it dosent seem to work , it simply keeps the pump switched on although all the levels are submerged.</p><p>what possibly could be the problems ?</p><p>Please help me with it . </p><p>I can provide images if you need them.</p>
Hi there DarshP5,<br><br>Please provide pictures showing all electrodes in overhead tank which is the one that controls pump operation. <br><br>rlarios<br><br>
<p>First I tried using a aluminium strip , but the circuit dint work , so i used a metal Screw as i had tested with metal screws in the bucket, i have posted the pictures of them all , the black and blue wires are the ground , green is the lower level and the red one is the upper level , and the blue one is the pump protect. (dont worry the pump protect and the ground wires are submerged in the underground tank.) and the other wires are as shown in the picture. Any Help Would Be Appreciated . :) thanks<br></p>
<p>DarshP5,</p><p>Wires wrapped around screws the way it's shown in pictures won't work properly. Crimp round terminals to wires ends and fasten terminals to either stainless steel or galvanized bolts using nuts and washers for a secured connection so they can be used as electrodes. </p><p>I believe you can find these bolts, nuts and washers at home depot or your local hardware store.</p><p>Let me know how this works. If you're still stuck with it at least we know electrodes won't be a problem. </p><p>rlarios</p>
<p>hey , sorry for the late reply.</p><p>i found out the problem , it was a small cut in the ground trace of the PCB , i fixed it, but now the circuit is acting weird , as it turns on the pump as soon as the water goes below the upper level. and then, the pump protect seems not to work and infact the circuit only works only when they are out of water. Its confusing ! please help :)</p>
DarshP5,<br><br>Show me a picture of solder side of your PCB.<br><br>rlarios<br>
<p>Sure, here it is </p>
First clean flux residue with a cotton swab soaked in alcohol. Make sure board is clean on component side as well.<br><br>Let me know if it still doesn't work so we continue debugging your control board.<br><br>rlarios
<p>Is this circuit is operate on AC current?</p>
<p>it depends on what you mean by that. Circuit operates on dc and I've seen some varying low voltage can be used and then rectified in order to be detected. </p><p>There are other circuits out there that operate off ac power using relays, in case you're interested look them up on YouTube. </p><p>rlarios</p>
<p>What to do to circuit to operate it on DC....</p>
<p>See comments below. </p>
<p>please can you send me the grafcet explain the operation of this project ???</p>
<p>please can you send me the grafcet explain the operation of this project ???</p>
<p>I put the cd 4001 in with pin 1 towards r1. Is that correct?</p><p>Better pictures would be nice for those of us who are color blind and too old to read tiny things.</p><p>Big question is can I substitute float switches for the top and bottom sensors to ground?</p><p>I could guess the 12 v dc needs to be on until the water lowers and breaks the circuit for the bottom sensor, and rises and finally breaks the circuit for the top one.</p><p>or vice a versa - My floats can go either way.</p><p>Going to use this to run a vegetable hydroponic garden on the balcony of my appt. About half of the time their roots will be submerged. </p><p>Have heard that plants are highly reactive (grow faster) to voltages - would like to run two test - one with the roots being grounded and the top of the plant with a weak dc positive charge, and another with the inverse. (will be an interesting test)</p><p>can I do that with this circuit? At least one of them?</p>
<p>Dear MikeL50,</p><p>Please review attached image. This DIP (Dual In-line Package) has an index mark on one end. Hold the IC so this mark is at your left, then the first pin below this mark is pin 1. Hand sketched drawing will show the pinout of this IC seen from the top.</p><p>Float switches (N.C.: Normally Closed) can be wired as shown in same picture as well. By the way, the attached picture was changed as previous one was not drawn correctly. </p><p>Hope this helps, let me know if you need anything else.</p><p>Regards</p><p>rlarios</p>
<p>MikeL50,</p><p>By the way, I forgot to confirm that CD4001 pin 1 goes to one end of R1 just as you said. The other end of R1 goes to +12V.</p><p>rlarios</p>
<p>Saq,</p><p>Replied though email and not sure if it will show up here in the forum or not. Try clicking the download pdf link, if not, go to the Jameco kit link below. Theory and schematic are in their docs I believe. Good stuff there. </p><p>Kid</p>
<p>can u mail me circuit diagram of this project.</p><p>shaikhsaqlain10@gmail.com</p>
<p>I built a radon mitigation system for my well water. This controller worked great!</p>
<p>hi, its a cool project, is there any way that i could get the pcb design?</p>
<p>Nice one! I have built a similar one on a bread board and tested by keeping it running for about an hour. Ionization leads to deposits on the leads/terminals inserted in water. Won't this affect performance over time and hence, required cleaning of such inserted leads periodically? If yes, is there any way to avoid this?</p>
Hi rlarious I'm back ;)<br>I was just thinking can we replace the transformer from that circuit<br>i.e, can we directly use the 12v dc adapter supply for the circuit<br><br>Can u plz tell me which components should be removed for that or how will the circuit be look like after doing that<br><br>I think those 4 diodes, 7812 voltage regulator should be removed but what about the capacitor<br>Plz help me out soon
<p>Remove capacitor as well. If wires from DC supply are longer than 3 inches, install a 0.1uF cap.</p><p>One more thing, make sure your DC PS is isolated from the mains by means of a transformer.</p><p>Good luck.</p>
Could you plz upload an image of the new schematic for the dc adapter, as I'm having some trouble with it right now<br>Thanks once again.
<p>The DC adapter you intend to use should have an isolation transformer inside. This means, there must not be any electrical connection between mains and the adapter's output such as is the case when these adapter's rely on auto transformers. The +12V DC and ground wires from your adapter would go to the +12V rail and ground line of the circuit, respectively. Forget about the 0.1uF capacitor. This is simple, just two wires from your adapter to the control.</p><p>rlarios</p>
One more thing shall i remove all the capacitors , 4 diodes, and 7812 regulator
<p>Remove D1, D2, D3, D4, C1, C2, and 7812 voltage regulator. Leave C3 installed.</p>
this design for water level control is the best i have seen in terms of simplicity of design and dedication to control limits. How can i get about 25 pcs of the pcb used in the design?, as other components is already available here.
Stevobaba411,<br><br>Unfortunately, the only source for ready built kits is jameco:<br><br>http://www.jameco.com/webapp/wcs/stores/servlet/Product_10001_10001_2169109_-1<br><br>Thanks for your comments.<br><br>rlarios<br>
Thanks a lot rlarious for such a great project<br>But i am facing some problem<br>Whenever i start the circuit<br>With or without the ic<br>The relay stays on no matter which condition it satisfies<br>So i thought to try the solution you told to vickys11<br>After doing that<br>The voltage supply for in condition i.e, when wires are dipped in water are perfectly the same reading but the voltage reading for the out condition<br>When wires are not in the water<br>The reading comes out to be 3.6 v instead of 8 to 9 v<br><br>Plz help me out soon as i need to submit my project<br><br>And yes the last question asked my vickys11 does make sense to me<br>As it will make the circuit smaller and less complex <br>Thanks a lot again.....
<p>Make sure pull up resistors are 2.2 M-Ohm. </p><p>Check your circuit very well. Also, make sure you are using a CD4001 IC. The readings you should get are consistent when tested with tap water or well water. If you're using distilled water, it won't work. Remember, 2.2 M-Ohm resistors form a voltage divider with water.</p><p>Good luck.</p>
Thanks rlarious<br>That was my mistake which i figured it out<br>Thanks to u<br><br>The circuit is working just fine but the red led is set to be turned on 24/7 no change is taking place when the inputs are been changed.
<p>Are you using same transistors and resistor values? The only function of those transistors is to turn red LED on and off depending on water level at pump protect electrode.</p>
Thanks a lot rlarios !!!!!<br>I know replying after a long time. ;)<br>Its finally working now<br><br>I just had a one more doubt<br>I made this circuit on pcb board home made using etching process<br>My ques was that<br>Can i use this circuit for a long period of time lets say 5-6 years<br>And can i turn on the circuit for 24/7<br>Can that create a problem using it for 24/7<br>Hope you will help me out soon<br>Thanks ;)

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