Float Switch Failure- Take Two

This forum has been a great help in times past in providing guidance for setting up float switches in a cistern. I have a dry hole for a well, with the well pump (protected) flowing into a cistern from which a house supply pump pressurizes storage tanks. Initially I had one float switch acquired through McMaster-Carr which failed me, flooding our finished basement. The sages here told me you should always use two float switches in series with an alarm, which was the setup I used next, and it worked fine for awhile. This failed me in the opposite extreme, inconveniently when I was away on business. The cistern went dry, my wife called me saying the house supply pump was running continually; thankfully the pump did not burn up, but it did require a plumber to prime it. This happened in January, and out of frustration with failures with an automatic system we have been manually monitoring and adding to the cistern level.

The monitoring is growing tedious, I would like to return to an automatic, reliable system. Any other thoughts out there? A friend recommended a commercial dishwasher water control setup, with upper and lower level settings and alarm. Does anyone here know of these being used for such a purpose, or what else I might try? TIA!!!

I use upper float switches and lower float swithes in my storage tank set ups. I beleive they are mercury switches and have found they work great. You can get them from your local well guy or a septic guy if you have aerobic systems where you live. Hope this helps, I don't remember the manufacturer but if you still need help I can get that info for you or get them and ship them to you.

You can get top quality float switches from Graingers, not mercury any more, but very reliable. This float switch can control a contactor that turns the pump on and off, then a high water alarm, either another float switch or a water sensor type liquid alarm can be wired to cut out the power to the contactor. Pretty hard for this to fail.

I suspect some defect in the manner of installation, it could be a small matter, but it can cause these odd failures. I would have the longest lived pump company in the area have a look at the set up.

Good advice ballvalve or atleast have more than one look at it and see which ones collaborate with one another.