Maker Pro
Maker Pro

Newbie: Auto shut-off for water pump based on water-level

Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.

The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.

I intend to do it all by myself using basic components and no ready
made kits.

The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?

Ok, all of the above is just theory. I've never touched electronics
before... any advice much appreciated.

So, in summary i am looking for:
1. How to turn off the motor when tank is full?
2. Any info about how to do it?
3. What equipment would i need to do it?

ps. If this is the wrong group to be posting this to, could you guide
me to the right one...

thanks...
 
Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.
The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.
I intend to do it all by myself using basic components and no ready
made kits.
The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?
Ok, all of the above is just theory. I've never touched electronics
before... any advice much appreciated.
So, in summary i am looking for:
1. How to turn off the motor when tank is full?
2. Any info about how to do it?
3. What equipment would i need to do it?
ps. If this is the wrong group to be posting this to, could you guide
me to the right one...
thanks...
There is a float device you can get which looks like a flattened ball
with a cable out of one end. You mount it with the cable tethered to
the side of the tank. It has a switch built in which activates when the
float is tilted downward from the cable end, ie: when the level is low.
Connect a device like this to a small mains /motor rated relay and
you have the whole problem solved.
Regards, KT
 
T

Terry Pinnell

Jan 1, 1970
0
Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.

The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.

I intend to do it all by myself using basic components and no ready
made kits.

The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?

Ok, all of the above is just theory. I've never touched electronics
before... any advice much appreciated.

So, in summary i am looking for:
1. How to turn off the motor when tank is full?
2. Any info about how to do it?
3. What equipment would i need to do it?

ps. If this is the wrong group to be posting this to, could you guide
me to the right one...

thanks...

It's not clear to me how it works at *present*? What switches the pump
off? And on again? Presumably you don't switch it on manually and then
periodically traipse upstairs to see whether the tank is full?

Anyway, I reckon you could easily adapt this circuit I suggested a
while ago:
http://www.terrypin.dial.pipex.com/Images/AquariumPump.gif

Just remove Float switch 1 for the extra 'reservoir' that was needed
in that aquarium application, and the associated components D1, D2 and
R2.

If you'd prefer to use an NPN transistor to drive the relay, use pin 3
instead of pin 4.

This is just a simple bistable circuit, edge-triggered by the float
switches so that it latches into an appropriate state until the
alternative switch is triggered.

You don't mention any need for a second float switch (hence my
question about how the pump gets switched on at present). If you don't
need one then you could replace that switch with a push-button to
start the pump manually.

If you want an even simpler approach (or an added precaution), wire
the supply to the motor relay through contacts activated by the float,
guaranteeing that the pump cannot operate above a certain level.

And check your overflow pipe!
 
B

Bob Masta

Jan 1, 1970
0
Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.

The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.

I intend to do it all by myself using basic components and no ready
made kits.

The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?

Ok, all of the above is just theory. I've never touched electronics
before... any advice much appreciated.

So, in summary i am looking for:
1. How to turn off the motor when tank is full?
2. Any info about how to do it?
3. What equipment would i need to do it?

ps. If this is the wrong group to be posting this to, could you guide
me to the right one...

thanks...

Take a look at Electronic Design, Nov 29,2004, page 90:
"Simple Circuit Maintains Water Level Between Two Preset Limits".
No floats needed!

Best regards,


Bob Masta
dqatechATdaqartaDOTcom

D A Q A R T A
Data AcQuisition And Real-Time Analysis
www.daqarta.com
 
M

Mike

Jan 1, 1970
0
I think your schematic is beyond the abilities of a beginner that has never
touched electronics. Even to me your schematic is a bit fuzzy, and I have
had my feet wet in "basic" electronics for some time now... Isn't that a
little extreme?

Mike
 
C

CFoley1064

Jan 1, 1970
0
Subject: Re: Newbie: Auto shut-off for water pump based on water-level
From: [email protected]
Date: 12/7/2004 3:56 AM Central Standard Time
Message-id: <[email protected]>


There is a float device you can get which looks like a flattened ball
with a cable out of one end. You mount it with the cable tethered to
the side of the tank. It has a switch built in which activates when the
float is tilted downward from the cable end, ie: when the level is low.
Connect a device like this to a small mains /motor rated relay and
you have the whole problem solved.
Regards, KT

I'd like to second the motion. Grainger has the Dayton 3BY58 for $22.84 USD,
just as described in KT's response, which is made to switch pump motor loads
(60 amp starting, 15A running). This is a trivial low cost solution to your
problem.

Also:

* As a "newbie", you're going to have to be careful with the presence of water
around electronics for various reasons, safety being the first. Starting out
your career in practical electronics with a line voltage project isn't a good
idea.

* In switching a motor, you may have problems with switch/contact arcing which
might cause a complex circuit to be upset because of EMI

* Even if you do have an overflow pipe, something experimental that can cost
you significantly usually isn't a good idea for someone new to the art. In the
event of device failure, best case is an astronomical water bill. Worst case,
a swamped house. Pass on this one.

Look up the device on the Grainger site and see if you can find anything like
this locally -- I don't think you'll have any problem:

http://www.grainger.com/Grainger/productdetail.jsp?xi=xi&ItemId=1613540157
&ccitem=

I'm not trying to sound harsh, but if you'd just like to try a simple
educational circuit "to get your feet wet", look at something else.

Good luck
Chris
 
R

Rich Grise

Jan 1, 1970
0
Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.

The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.

I intend to do it all by myself using basic components and no ready
made kits.

The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?

Ok, all of the above is just theory. I've never touched electronics
before... any advice much appreciated.

So, in summary i am looking for:
1. How to turn off the motor when tank is full?
2. Any info about how to do it?
3. What equipment would i need to do it?

Go to your local home warehouse store and take a look at some sump pumps.
They have a float with a couple of switches or maybe even a mechanical
actuator. You could even ask around for a worn-out sump pump and just take
off the switch assembly.

Good Luck!
Rich
 
T

Terry

Jan 1, 1970
0
Hi there,

I am a complete newbie to electronics but am a computer geek (the
software side). I am trying to get my feet wet with an electronics
project.

The problem:
There is a electrical water-pump in my house that fills a water-tank
that's up on the third floor. You need to climb a million stairs to
check the level in that tank so that the water doesn't spill.

I intend to do it all by myself using basic components and no ready
made kits.

The solution?
I am thinking on the lines of a float-ball attached with a lever that
closes a circuit when a certail level is reached. Now i know that the
tank is full but how do i turn off the motor? Do i use a circuit
breaker? if so how do i trip it?
Exactly; it's not electronics; unless you want to make it so! It's simple
on/off switch logic; controlled by the water level.

Electricity flows through a normally 'ON' closed (in the low/empty position)
float switch to actuate the pump.
A true float switch will be designed to switch off and on the somewhat
inductive load of, for example, a one third HP pump motor. Typically such a
switch will last for 15 to 20 years, depending how often it cycles on/off.

Water flows to tank, float rises, when water reaches the level you have
preset the float switch 'OFF' and opens the circuit and electricity ceases
to flow to the pump.
That in its simplest form is how it would work. The float switch may have
some sort of mechanical adjustment so that after the water is at the level
you want it is allowed to fall again to certain extent before the pump
operates again to refill the tank. If float switch is too sensitive to the
water level the float switch will operate the pump every time someone takes
one cup of water! And the pump will operate too many times.

Also if the pumping rate is very fast/high and someone is running water
continuously (to fill a bath tub say) the pump may fill the tank more
quickly than the outflow so it will cut in and out several times. This may
or may not be a problem for you? You may be able to adjust the pump flow
rate with a simple water valve, to avoid that.

MOST IMPORTANT. Have a gravity overflow; very slightly above your desired
water level! Something may misoperate; without overflow there will be steady
flow of water over the lip of the tank down through the ceilings and house
structure until pump is manually turned off. (BTW I've seen software that
omits that kind of 'what happens if' thinking!).
Also make sure the overflow can't (depending on your climate?) freeze
shut/blocked! Or goes to a drain that cannot block or backup. That is the
over flow pipe should be of sufficient size to handle the gravity overflow.
Whereas the fill pipe from the pump is at pressure!

If it is undesirable to run household AC up to the float switch on the tank
and thence down to the pump, a more complicated (perhaps low voltage )
circuit could be devised' that could operate a relay that would actually
switch on the pump? But that means more components (I can think of at least
three more electrical parts and more cost) and insufficient info is
available about what you are trying to accomplish?

However I would comment that in all these situations 'The simpler the
better'. If possible use standard and available parts. It's a waste of time
to spend a long weekend trying to analyze why something doesn't work when a
quick trip to the hardware store or building supplier, perhaps fifteen years
from now, by someone will provide a most likely similar/identical standard
float switch etc.

Sounds like this is a practical plumbing and float switch job.
 
R

Rich Grise

Jan 1, 1970
0
Exactly; it's not electronics; unless you want to make it so! It's simple
on/off switch logic; controlled by the water level.

Electricity flows through a normally 'ON' closed (in the low/empty position)
float switch to actuate the pump.
A true float switch will be designed to switch off and on the somewhat
inductive load of, for example, a one third HP pump motor. Typically such a
switch will last for 15 to 20 years, depending how often it cycles on/off.

Water flows to tank, float rises, when water reaches the level you have
preset the float switch 'OFF' and opens the circuit and electricity ceases
to flow to the pump.
That in its simplest form is how it would work. The float switch may have
some sort of mechanical adjustment so that after the water is at the level
you want it is allowed to fall again to certain extent before the pump
operates again to refill the tank. If float switch is too sensitive to the
water level the float switch will operate the pump every time someone takes
one cup of water! And the pump will operate too many times.

Also if the pumping rate is very fast/high and someone is running water
continuously (to fill a bath tub say) the pump may fill the tank more
quickly than the outflow so it will cut in and out several times. This may
or may not be a problem for you? You may be able to adjust the pump flow
rate with a simple water valve, to avoid that.

MOST IMPORTANT. Have a gravity overflow; very slightly above your desired
water level! Something may misoperate; without overflow there will be steady
flow of water over the lip of the tank down through the ceilings and house
structure until pump is manually turned off. (BTW I've seen software that
omits that kind of 'what happens if' thinking!).
Also make sure the overflow can't (depending on your climate?) freeze
shut/blocked! Or goes to a drain that cannot block or backup. That is the
over flow pipe should be of sufficient size to handle the gravity overflow.
Whereas the fill pipe from the pump is at pressure!

If it is undesirable to run household AC up to the float switch on the tank
and thence down to the pump, a more complicated (perhaps low voltage )
circuit could be devised' that could operate a relay that would actually
switch on the pump? But that means more components (I can think of at least
three more electrical parts and more cost) and insufficient info is
available about what you are trying to accomplish?

However I would comment that in all these situations 'The simpler the
better'. If possible use standard and available parts. It's a waste of time
to spend a long weekend trying to analyze why something doesn't work when a
quick trip to the hardware store or building supplier, perhaps fifteen years
from now, by someone will provide a most likely similar/identical standard
float switch etc.

Sounds like this is a practical plumbing and float switch job.

How about a toilet tank float and a pressure switch?

Cheers!
Rich
 
A

ali

Jan 1, 1970
0
Thanks everyone, this was enlightening...

My main motivation was not to solve the problem, but to learn some
electronics. If the problem got solved, that's just a side-effect ;).
So based on all of your kind input, i think i will change the project a
bit.

I think i'll just hook the float to a rheostat or pot (i don't really
know which at the moment) and hook the pot to an LED display which
would be downstairs and would tell me about the level of water. I can
turn off the pump manually with the help of the display. Surely, i hope
this is electronics and not just plumbing ;).

Anyway, i'll read up on all these links and be back when i get stuck...
Thanks once again...
 
R

Rich Grise

Jan 1, 1970
0
Thanks everyone, this was enlightening...

My main motivation was not to solve the problem, but to learn some
electronics. If the problem got solved, that's just a side-effect ;).
So based on all of your kind input, i think i will change the project a
bit.

I think i'll just hook the float to a rheostat or pot (i don't really
know which at the moment) and hook the pot to an LED display which
would be downstairs and would tell me about the level of water. I can
turn off the pump manually with the help of the display. Surely, i hope
this is electronics and not just plumbing ;).

Anyway, i'll read up on all these links and be back when i get stuck...
Thanks once again...

Here's some data sheets for bar graph displays:
http://www.google.com/search?q=lm3914+data+sheet&btnG=Google+Search

If the position of the pot is really proportional to the water level,
this chip makes a really cool "gas gauge." Of course, you stilll have to
learn enough of Ohm's Law to know what voltages to apply at the pot and
how its position actually affects the voltage at the error amp input...

Good Luck!
Rich
 
G

Gordon Youd

Jan 1, 1970
0
HI, I would suggest a normal float valve to let the water into the tank and
a simple pressure switch(RS Supplies) downstairs on the feed pipe to the
tank.

Tank empty, = floatvalve open = no back pressure, = pump on.

Tank full, = floatvalve closed = back pressure = pump off.

Just a suggestion :)

Kind regards, Gordon.
 
R

Raul

Jan 1, 1970
0
Hi, I realize you want to build something yourself but you might try a
marine store to get some ideas. They have all kinds of water
activated/deactivated switches for pumps.
Raul
 
L

Louis Bybee

Jan 1, 1970
0
Raul said:
Hi, I realize you want to build something yourself but you might try a
marine store to get some ideas. They have all kinds of water
activated/deactivated switches for pumps.
Raul

One easy to find switch that might be ideal for his application is the water
level sensing switch used on most washing machines. Although suitable for
pilot duty only, a visit to any appliance junk yard should be rewarding. The
cost, flexibility of application, and availability, should make one a good
fit.

Louis--
*********************************************
Remove the two fish in address to respond
 
K

kevreh

Jan 1, 1970
0
Go to this site: http://reefcentral.com/forums/index.php

And do a search in the DIY forum. Reef tank folks (including myself) have
discussed this quite a bit. I don't want to sound like I'm sending you
somewhere else but there's so many different ways to approach it and issues
to consider.

Personally, I use a float switch from grainger that controls a solenoid
valve. I use it to let RO water into my tank. Some people take an extra step
and use both a low limit and high level limit float switch. As mentioned
previously simplicity is key since water + electricity a)don't mix and b)are
prone to failure.

Kevin
 
Top