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

From: Gordon Youd (gordon_at_Zgyoud.demon.co.uk)
Date: 12/12/04 

Date: Sun, 12 Dec 2004 01:08:09 -0000

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.

--------------------------------------------------------

"Rich Grise" <rich@example.net> wrote in message
news:pan.2004.12.09.07.25.25.177852@example.net...
> On Thu, 09 Dec 2004 01:05:22 -0330, Terry wrote:
>
>>
>> <ali.jan@gmail.com> wrote in message
>> news:1102401843.206541.80550@z14g2000cwz.googlegroups.com...
>>> 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.
>
> How about a toilet tank float and a pressure switch?
>
> Cheers!
> Rich
>

Relevant Pages

  • Re: Looking for a hot-water tank controller
    ... solenoid-operated valve on the cold water inlet and the 230v supply to ... the float switch could be a flow switch in the drain line ... from the drain pan. ... going on vacation turn your tank off. ...
    (alt.home.repair)
  • Re: Newbie: Auto shut-off for water pump based on water-level
    ... >> check the level in that tank so that the water doesn't spill. ... > 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. ...
    (sci.electronics.basics)
  • Re: Auto-leveling aquariums....
    ... float valve swtiches directly to the sump. ... I figured that at the rate the water is ... > a resivoir and controled by 2 float switches in each tank. ...
    (rec.aquaria.freshwater.misc)
  • Re: Auto-leveling aquariums....
    ... Fishman wrote: ... > Kent float valve swtiches directly to the sump. ... > had RO/DI water going directly into the sump. ... >> controled by 2 float switches in each tank. ...
    (rec.aquaria.freshwater.misc)
  • Re: Heated Bathtub or Whirlpool or Whatever?
    ... Todd H. wrote: ... There would probably also need to be circulation of water during this ... Any float tank should be tweakable to achieve these goals, ...
    (misc.consumers.house)