# Tank level control with floats help



## Jack30802 (Jul 6, 2013)

How should I go about wiring a float level system on a 500 gal tank I need to turn on at 100 gals and cut off at 425 but can't seam to figure it out thanks I'm using it to pump in


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## Wirenuting (Sep 12, 2010)

Jack30802 said:


> How should I go about wiring a float level system on a 500 gal tank I need to turn on at 100 gals and cut off at 425 but can't seam to figure it out thanks I'm using it to pump in


I forget the brand, but we had a 5k tank and used a separate float container. 
It used reed switches to see the level in the large tank. The SS float triggered the reed switches.
It was an air over water system at 120#s.


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## xlink (Mar 12, 2012)

Do you need help selecting the floats or wiring the controls?


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## dronai (Apr 11, 2011)

Need more info.


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## Jack30802 (Jul 6, 2013)

More with the wiring I'm thinking bottom float at 100 gals nc while floating then top float at 425 NC until its float then it will kill power to pump that's pumping inn but I'm lost on how to make it work going back down and re starting


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## dronai (Apr 11, 2011)

Jack30802 said:


> More with the wiring I'm thinking bottom float at 100 gals nc while floating then top float at 425 NC until its float then it will kill power to pump that's pumping inn but I'm lost on how to make it work going back down and re starting


 
I think this is it; pump turns on when NO contacts are made, and turns off when NO float closes and NC contacts break.


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## Semi-Ret Electrician (Nov 10, 2011)

Jack30802 said:


> More with the wiring I'm thinking bottom float at 100 gals nc while floating then top float at 425 NC until its float then it will kill power to pump that's pumping inn but I'm lost on how to make it work going back down and re starting


Here's one that will do the trick, as long as the liquid is conductive. They will provide a wiring diagram and you will also need a 3 prong probe, no floats.
http://ecatalog.gemssensors.com/ecatalog/warrick-controls/en/16MA1A0


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## glen1971 (Oct 10, 2012)

dronai said:


> I think this is it; pump turns on when NO contacts are made, and turns off when NO float closes and NC contacts break. Maybe one 2 pole relay


The only problem I can see with the drawing, is that once the pump turns off it will start again when the upper float drops to it's open condition.. This could cause the pump to cycle a fair amount.


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## dronai (Apr 11, 2011)

glen1971 said:


> The only problem I can see with the drawing, is that once the pump turns off it will start again when the upper float drops to it's open condition.. This could cause the pump to cycle a fair amount.


 
Yeah, I just saw that too :laughing: Thinking about how to let the level drop back down to 100 gal mark before restarting


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## Jlarson (Jun 28, 2009)

Wire it much like a motor stop/start circuit. 2 NC floats instead of a NO and an NC stop and start button. 

Floats won't be hugely accurate though.


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## dronai (Apr 11, 2011)

I'm confused Larson, If NC all starts, and 1 stop what are the contacts on the relay NO or NC ?


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## Jlarson (Jun 28, 2009)

Semi-Ret Electrician said:


> Here's one that will do the trick, as long as the liquid is conductive. They will provide a wiring diagram and you will also need a 3 prong probe, no floats.
> http://ecatalog.gemssensors.com/ecatalog/warrick-controls/en/16MA1A0


Warricks would be more accurate, use the tank dimensions and some math to figure the heights to set the probes at.


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## BBQ (Nov 16, 2010)

Jlarson said:


> Warricks would be more accurate, use the tank dimensions and some math to figure the heights to set the probes at.


Screw that math stuff, are you trying to be like Piperunner?:laughing:


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## Jack30802 (Jul 6, 2013)

It don't have to be perfect on 100 I been using a utra sonic senor but they have been failing due to being outside they post to be weather proof but are just not holding up and as far level probes I we have them on some of our machine s just want to try floats on one cause some time the liguid we are controlling wont work with level probes for some reason


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## 8V71 (Dec 23, 2011)

This would be the logic involved. Float switches are normally closed. To seperate low voltage from high voltage would require small changes but the logic is the same.


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## tates1882 (Sep 3, 2010)

Jack30802 said:


> How should I go about wiring a float level system on a 500 gal tank I need to turn on at 100 gals and cut off at 425 but can't seam to figure it out thanks I'm using it to pump in


The wiring is pretty simple. Are you using no or nc floats, Ice cube relays or Plc, is there a low level float too? It's all about getting weights on the floats right so the pumps don't cycle constantly.


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## dronai (Apr 11, 2011)

8V71 said:


> This would be the logic involved. Everything is normally closed. To seperate low voltage from high voltage would require a small change but the logic is the same.
> 
> View attachment 26915


 
In your drawing everything is closed, so the CR is always energized


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## dronai (Apr 11, 2011)

tates1882 said:


> The wiring is pretty simple. Are you using no or nc floats, Ice cube relays or Plc, is there a low level float too? It's all about getting weights on the floats right so the pumps don't cycle constantly.


A PLC would eliminate all the relays it would take to do this. They have weights that could delay the low float to not cycle back on so fast ?


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## 8V71 (Dec 23, 2011)

dronai said:


> In your drawing everything is closed, so the CR is always energized


Only at the very start when filling the tank for the first time.


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## dronai (Apr 11, 2011)

8V71 said:


> Only at the very start when filling the tank for the first time.


 
Your floats are in series to 1 relay right ? You then have a latching contact from this 1 relay right ? You then have another NC contact called CR 2 on the next rung I guess to the motor right ?


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## 8V71 (Dec 23, 2011)

I forgot to add power to the contactor. I changed my circuit to a mid-fill off state so I could correctly identify the NO contacts for less confusion.


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## erics37 (May 7, 2009)

dronai said:


> Yeah, I just saw that too :laughing: Thinking about how to let the level drop back down to 100 gal mark before restarting


Holding contacts around the High float. And put them in series with each other and a single control relay coil, then use that to control the starter.

Or just use a better level system than floats, like others suggest :thumbup:


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## 8V71 (Dec 23, 2011)

.....


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## dronai (Apr 11, 2011)

erics37 said:


> Holding contacts around the High float. And put them in series with each other and a single control relay coil, then use that to control the starter.


I will draw out what you are suggesting for practice to see if it makes sense to me.

In the meantime I found this one. Seems to be what the guy is looking for. Someone said use a DPDT relay with one going to the holding contact, and 2 floats. I would like to see this in ladder.


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## erics37 (May 7, 2009)

dronai said:


> I will draw out what you are suggesting for practice to see if it makes sense to me.
> 
> In the meantime I found this one. Seems to be what the guy is looking for. Someone said use a DPDT relay with one going to the holding contact, and 2 floats.


Something like this, but I forgot if the OP is filling or emptying the tank. Either way it's the same, just flip some NCs and NOs around or whatever.


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## JRaef (Mar 23, 2009)

No need for a relay.

Assuming tank fill.

LL float is NC, opens on level rise. LL NC contact in series with starter coil.

HL float is NC, opens on level rise. HL NC in series with starter coil and LL NC

Starter NO aux. contact seal-in goes around LL float. 

At drop to 100gal, LL contact closes, starter closes, seals in around LL contact so that when water enters and raises LL switch, pump continues to run. Runs until HL contact opens, which drops out the starter until LL closes again.


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## 8V71 (Dec 23, 2011)

knead knot


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## 8V71 (Dec 23, 2011)

dronai said:


> Your floats are in series to 1 relay right ? You then have a latching contact from this 1 relay right ? You then have another NC contact called CR 2 on the next rung I guess to the motor right ?


Sorry I missed this. Yes to everything except I mentioned C1 and C2 were NC but they are NO contacts. I was thinking about your questions and forgot that my drawing was in the "on" state and filling from empty. I changed it to mid-level and not pumping to avoid confusion.


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## dronai (Apr 11, 2011)

I think this is what Jreafs would look like


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## 8V71 (Dec 23, 2011)

I have never drawn in ladder but at the least I see a need for a seal across Low FLT. Never heard of seal either but I mean latching.


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## ScooterMcGavin (Jan 24, 2011)

I think this is what JRaef was talking about. I just added a hand off auto switch to the system.


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## 8V71 (Dec 23, 2011)

dronai. your message box is full.


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## dronai (Apr 11, 2011)

scameron81 said:


> I think this is what JRaef was talking about. I just added a hand off auto switch to the system.


*I like your HOA switch addition*



8V71 said:


> dronai. your message box is full.


Emptied !


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## Jlarson (Jun 28, 2009)

The hell? How'd y'all manage to over complicate 2 floats and a starter? :lol:


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## drspec (Sep 29, 2012)

Jlarson said:


> The hell? How'd y'all manage to over complicate 2 floats and a starter? :lol:


It's the ET way :thumbup:


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## Jack30802 (Jul 6, 2013)

So have we found a working layout lol? I might be better off building a top for the electronic senor


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## xlink (Mar 12, 2012)

Jack30802 said:


> So have we found a working layout lol? I might be better off building a top for the electronic senor


If you think this is bad, post a picture of your work when it's done.


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## Jack30802 (Jul 6, 2013)

Hey don't take it the wrong way I was just joking i didn't know it would be so much and Im still a rookie so I have no room to talk


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## Jack30802 (Jul 6, 2013)

Well ending up going with warrick probes thanks for advice guys first post and so much help downloaded app today new fav fourm


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## Semi-Ret Electrician (Nov 10, 2011)

Jack30802 said:


> Well ending up going with warrick probes thanks for advice guys first post and so much help downloaded app today new fav fourm


They will be a lot cheaper to install and maintain, no moving parts, no cleaning. I've used them for years, never had a problem:thumbsup:


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## Jlarson (Jun 28, 2009)

BBQ said:


> Screw that math stuff, are you trying to be like Piperunner?:laughing:


:lol:


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## Semi-Ret Electrician (Nov 10, 2011)

No math. Cut two long probes at the LLL, cut the top probe at the HLL.

If it has to be exact fill with water to the LLL, mark the spot, continue the fill to the HLL, mark the spot.


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## ScooterMcGavin (Jan 24, 2011)

+1 for the war rick probes. We use them everywhere and in very critical applications where they must work. One thing to keep in mind is that they have a direct mode and an inverse mode. Direct mode energizes the relay when the probes touch water. Inverse mode de-energizes the relay when the probe touches. 

We generally use inverse mode because often times we use the probes as a last line of defense for high level and spill prevention, so that if the relay dies or malfunctions we will get the high level alarm and we know there is a problem with it. Otherwise it could die and you wouldn't know it until its too late. I'm not sure if it applies in your application but its something to consider.


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## Semi-Ret Electrician (Nov 10, 2011)

scameron81 said:


> +1 for the war rick probes. We use them everywhere and in very critical applications where they must work. One thing to keep in mind is that they have a direct mode and an inverse mode. Direct mode energizes the relay when the probes touch water. Inverse mode de-energizes the relay when the probe touches.
> 
> We generally use inverse mode because often times we use the probes as a last line of defense for high level and spill prevention, so that if the relay dies or malfunctions we will get the high level alarm and we know there is a problem with it. Otherwise it could die and you wouldn't know it until its too late. I'm not sure if it applies in your application but its something to consider.


True and, the fluid MUST be conductive. Rules out pure water and oil based fluids. So, is great for oil-water interface detection


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