Float Switch

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Kingston

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I have a situation where water comes on only twice a week. The pressure isn't strong so it needs to be pumped up two flights to a water tank on the roof. With that said I wanted to have a float switch in the PVC pipe that turns the pump on when the pipe fills up. There would be another float switch in the tank on the roof that would turn the pump off when the tank was full.

I bought the following float switches.
http://www.amazon.com/uxcell-Pieces-ZP4510-Vertical-Switches/dp/B00FHAEBIA?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

I bought the following pump.
http://www.amazon.com/Neiko-50639-I...&redirect=true&ref_=oh_aui_detailpage_o07_s00

I need a relay so the float switch can control the pump. Can anyone provide me a link to finding that?

I understand there are more expensive ways to do this but I'm trying to make and donate a number of these systems to people that need water.

Thanks in advance.
 
The first place that I would go is to a plumber to ask them or who they may know in that industry that may have experience in this area. You may aslson consider those in the well business are pump water pump type his messes, people who whould have experience in water handling and storage.
 
Kingston said:
I have a situation where water comes on only twice a week. The pressure isn't strong so it needs to be pumped up two flights to a water tank on the roof. With that said I wanted to have a float switch in the PVC pipe that turns the pump on when the pipe fills up. There would be another float switch in the tank on the roof that would turn the pump off when the tank was full.

I bought the following float switches.
http://www.amazon.com/uxcell-Pieces-ZP4510-Vertical-Switches/dp/B00FHAEBIA?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

I bought the following pump.
http://www.amazon.com/Neiko-50639-I...&redirect=true&ref_=oh_aui_detailpage_o07_s00

I need a relay so the float switch can control the pump. Can anyone provide me a link to finding that?

I understand there are more expensive ways to do this but I'm trying to make and donate a number of these systems to people that need water.

Thanks in advance.
Click to expand...

www.grainger.com
 
160413-1328 EDT

I suggest that you look at Warrick liquid level controls. Should provide greater reliability than float switches. No moving parts. The controls sense resistance change between air and a moderately conductive liquid with fixed probes that define the on and off sensing points.

See http://www.gemssensors.com/Level/Warrick/Conductivity-Based-Liquid-Level-Control

Fifty plus years ago I did some development work for Warrick when it was still a family owned company. Probably 30 years ago it became part of Gems.

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I used Warrick controls on my water system at home. 15 years and no failures. I would however, use them to control an ice cube relay to then operate your motor starter. Some versions also offer on delay or off delay, in order to avoid false tripping due to ripples in the water.
 
160413-1652 EDT

I don't know what has changed in Warrick systems since the days when I did development work for them.

The original system before I did my work was a high impedance AC 60 Hz transformer, connected to a sensitive AC relay with a probe to shunt the relay when the probed contacted a low enough impedance to bring the relay below its dropout point. By using one pole of the relay and two probes you could make a differential level control without time delays added. A very simple and reliable system. Also note the relay has a differential with respect to the pullin and dropout sensing impedance points.

I don't remember the relay specifications, but it may have been 1/3 to 1/2 HP for a motor.

My project was to devekop an electronic control for the relay that still used AC for sensing, was low voltage, and much less sensitive to supply voltage relative to the resistance threshold point. I used an AC bridge circuit. There is a reason for AC on the proble vs DC, and that is to eliminate a polarization effect that raises the apparent probe resistance with time of applied unidirectional voltage.

I doubt that the old Warrick relay design is still used, because of cost.

Photos of the relay with my electronic control are attached. This relay still works.

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PICT3872.jpgPICT3873.jpg

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gar said:
160413-1328 EDT

I suggest that you look at Warrick liquid level controls. Should provide greater reliability than float switches. No moving parts. The controls sense resistance change between air and a moderately conductive liquid with fixed probes that define the on and off sensing points.

See http://www.gemssensors.com/Level/Warrick/Conductivity-Based-Liquid-Level-Control

Fifty plus years ago I did some development work for Warrick when it was still a family owned company. Probably 30 years ago it became part of Gems.

.
Click to expand...


This guy knows what he is talking about. I would use a probe system also. You are not going to find an inexpensive float that will fit in a pipe and have good reliability.

There are other solutions to your problem though. In Haiti they use pumps with a pressure switch. When the pump fills the tank, a float closes the inlet valve on the fill pipe, the pump dead heads, pressure shoots up and the pressure switch opens.

2Q==


To turn the pump on, have a capacitance probe and liquid sensing relay to energize your motor starter.

A system like this would eliminate having to run conduit to the roof mounted tank.

But as the another gentleman mentioned, I am sure a local plumber has a better solution based on years of experience. The controls on this are very easy. The hard part is getting a set of probes into the pipe in a reliable way that does not leak.

Good luck!!!
 
Amazon page said:
Max Contact Rating;10W
Click to expand...
That is a REALLY poor rating for a control device. You cannot control very much with a contact rated for only 10W! Basically the only thing you can turn on with that float switch will be a small "ice cube" type relay, but then that relay cannot handle turning on a 1HP motor. For a motor that large, you are going to need a contactor but even a small contactor will use more than 10W for the coil. So you will need the float to turn on a relay to turn on the contactor. With all of that, you might be better off using a better float switch and run it right to a contactor.

And by the way, that pump is not self-priming, I hope you know what that means.
 
Jraef said:
That is a REALLY poor rating for a control device. You cannot control very much with a contact rated for only 10W! Basically the only thing you can turn on with that float switch will be a small "ice cube" type relay, but then that relay cannot handle turning on a 1HP motor. For a motor that large, you are going to need a contactor but even a small contactor will use more than 10W for the coil. So you will need the float to turn on a relay to turn on the contactor. With all of that, you might be better off using a better float switch and run it right to a contactor.

And by the way, that pump is not self-priming, I hope you know what that means.
Click to expand...


As Jraef said you have to prime it to begin with. It says it holds it's prime but if it loses it's prime someone has to go tend to it.
 
Kingston said:
I have a situation where water comes on only twice a week. The pressure isn't strong so it needs to be pumped up two flights to a water tank on the roof. With that said I wanted to have a float switch in the PVC pipe that turns the pump on when the pipe fills up. There would be another float switch in the tank on the roof that would turn the pump off when the tank was full.

I bought the following float switches.
http://www.amazon.com/uxcell-Pieces-ZP4510-Vertical-Switches/dp/B00FHAEBIA?ie=UTF8&psc=1&redirect=true&ref_=oh_aui_detailpage_o08_s00

I bought the following pump.
http://www.amazon.com/Neiko-50639-I...&redirect=true&ref_=oh_aui_detailpage_o07_s00

I need a relay so the float switch can control the pump. Can anyone provide me a link to finding that?

I understand there are more expensive ways to do this but I'm trying to make and donate a number of these systems to people that need water.

Thanks in advance.
Click to expand...
A little unclear of just what the application is. Are you saying the supply water is only available a couple times a week, and that you wish to fill a tank when there is supply water available?

The switch you provided a link for would work assuming you connect it to some low power controls, and as mentioned could short cycle if too small of a holding tank as you will start again with only a 1/2 inch or so draw down of tank level.

I think there would be better methods of detecting supply water - especially if detecting in a pipe, conductivity probes and associated controllers would probably be best for that.

If the supply has some pressure that should prime the pump, but you may want to detect presence of water on the discharge - that way it is primed before it is allowed to start.
 
As pointed out you won't be able to directly start a contactor (which you need to run your motor) without using another relay because of the low power rating of your switches.
Your switches are meant to be used with a low power control system. Something like the Eaton Easy smart relays and a small contactor. Then you will have a lot more control
options like delays, timers etc. In any case you'll need to spend more $ to make a working system. These run somewhere around $250 last time I looked.

http://www.eaton.com/Eaton/Products...lays/EASY500700800IntelligentRelays/index.htm
 
ez pz. use solid state relay, and power the float switches using low Vdc

i get my SSR's from Mouser. i can recommend part # if you tell me the specs of the pumps.
 
ok, that amzon pump is a 1hp, it will run right about 7A, so lets size SSR by 2x to ~15A.

use relay part #G3NA-220B-DC5-24 $27ea.
i use this brand/series for AC motors, and i go extra step of adding a dual "big" MOV's to help protect the SSR.


i am not confident that that pump can lift water to the height you are asking. it looks like 1" NPT fittings, you might need to reduce the outlet down to say 1/2" sched40 PVC for it to pump that high, but GPM will suffer.
 
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