What brand do you have that's failing. Around here everyone uses a=20
Square D, line voltage pressure switch, and it's next to never they go=20
bad. But if going the PIC route, check out this family @ $15

http://www.mouser.com/ProductDetail/Freescale-Semiconductor/MPX5700GP1/?qs=
=3Dr8OyiFxb6Rc9Emm4NZHQFL0WwDp2TJGWwqXdJbUhZqM%3d

On 6/13/2012 5:38 PM, Nily wrote:
> Look at this link:
> http://www.ebay.com/itm/Automatic-Water-Pump-Pressure-Controller-Electric=
-El
> ectronic-Switch-Control-Unit-/170850300264?pt=3DBI_Pumps&hash=3Ditem27c77=
8b168#h
> t_5495wt_952
>
> Ready to use electronic switch up to 10 bar for $ 38.00 and free shipping=
..
>
> Rodolfo
>
> -----Mensaje original-----
> De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]En nombre de
> Nily
> Enviado el: Miercoles, 13 de Junio de 2012 02:11 p.m.
> Para: Microcontroller discussion list - Public.
> Asunto: RE: [EE] cheap pressure sensor for water pump
>
>
> Just an idea, did you think using an elevated tank and a simple on/off
> switch to fill it ?
>
> cheers
>
> Rodolfo
>
> -----Mensaje original-----
> De: piclist-bounces@mit.edu [mailto:piclist-bounces@mit.edu]En nombre de
> KPL
> Enviado el: Miercoles, 13 de Junio de 2012 01:34 p.m.
> Para: Microcontroller discussion list - Public.
> Asunto: Re: [EE] cheap pressure sensor for water pump
>
>
> Pump is not a submersible type, and is located near the well.
> Everything else is located some distance away, with switch mounted
> just before the pressure vessel; Everything except the switch and pump
> was just replaced. I know about effects caused by water inertia in
> case of incorrect location of components, and that is not a problem.
> Most probably the switch you are using for 20 years was not made in
> china. Those that pretend to be made in Europe cost much more, and are
> not easy to find.
> Sorry, this is becoming quite bit off topic.
>
> The main idea is - I do not like that mechanical switch, and was
> dreaming about digitally controlled substitute for quite some time.
> Component sellers usually do not mention in their catalogs what medium
> their sensors are meant for, and it's quite a task to search all those
> datasheets. Usually those sensors cost quite a lot, but I do not need
> that high precision, since most probably any of them will be give more
> repeatable results than the mechanical switch.
>
> On Wed, Jun 13, 2012 at 9:36 PM, John Ferrell<jferrell13@triad.rr.com>
> wrote:
>   =20
>> Some where in the system there should be a pressure tank. The pressure
>> switch should be as close as possible to the tank. If there is a filter
>> in the system, it should be as close to the tank input as possible. The
>> wells around here are deep enough to require submersible pumps. The
>> pressure tanks have a diaphragm and an airspace. They sometimes need
>> replacement. The pressure switches last a very long time. I have lived
>> here for nearly 20 years and not needed a replacement.
>>
>>     =20
>
>
>
> --
> KPL
> --
> http://www.piclist.com PIC/SX FAQ&  list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.1913 / Virus Database: 2433/5067 - Release Date: 06/13/12
>
> --
> http://www.piclist.com PIC/SX FAQ&  list archive
> View/change your membership options at
> http://mailman.mit.edu/mailman/listinfo/piclist
>
>
> -----
> No virus found in this message.
> Checked by AVG - www.avg.com
> Version: 2012.0.1913 / Virus Database: 2433/5067 - Release Date: 06/13/12
>
>   =20
--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.