Some where in the system there should be a pressure tank. The pressure=20
switch should be as close as possible to the tank. If there is a filter=20
in the system, it should be as close to the tank input as possible. The=20
wells around here are deep enough to require submersible pumps. The=20
pressure tanks have a diaphragm and an airspace. They sometimes need=20
replacement. The pressure switches last a very long time. I have lived=20
here for nearly 20 years and not needed a replacement.

On 6/13/2012 4:57 AM, KPL wrote:
> Hi,
>
> I'm constantly having trouble with pressure switch of a water pump,
> which is supplying water from a well for a house and garden. Setup is
> far from optimal, and seems like normal, membrane-activated switches
> are having trouble with this. I am sure there are better switches
> available somewhere, but I had an idea to build one by myself, using a
> PIC. That way I could have better control of ON and OFF pressures, and
> hysteresis, probably also some kind of dynamic self-adjusting, to cope
> with completely different situations of supplying just home, vs
> supplying water for garden. Soft start of a pump motor could be
> implemented easily too.
>
> Any ideas what cheap pressure sensor could be used? Sensor has a
> direct contact with water.
> Some kind of a digital output would be best, but i can live with
> analog signal too.
> Best if that sensor is widely available, that is, used in some
> consumer equipment.
>
> Somebody recommended to use oil pressure sensor from a car, that has
> continuous-signal sensor, not just a pressure switch, but I do not
> have an exact car model that uses this kind of sensor.
> Probably sensor, designed to contact with oil, would not live very
> long with water, but it's ok to replace it sometimes if it's cheap
> enough.
>
> I'm interested in pressures between 1 and 6 bar, or so.
>

--=20
John Ferrell W8CCW
=93During times of universal deceit,
   Telling the TRUTH becomes a revolutionary act=94
      George Orwell




--=20
http://www.piclist.com PIC/SX FAQ & list archive
View/change your membership options at
http://mailman.mit.edu/mailman/listinfo/piclist
.