On Tue, 18 Aug 2009 13:46:57 +0100, dennis@home wrote:
The well would likely need to have the pump lowered down into it,
because most efficient types of pumps are not able to create enough
vacuum to draw the water up to them

Ours is 80' deep or so, with the pump at the top, but it needs to be
primed with water before it'll work (i.e. a well in the bore-hole sense,
rather than wide brickwork medieval shaft).

The pump can't be at the top, you can only raise water by 32 feet using a
vacuum.
The pump must be at the bottom where it can apply pressure to raise the
water by more than 32 feet.

It's at the top; surface-level pumps are very common out here. The
following seems to explain operation pretty well:

http://www.popularmechanics.com/home...36.html?page=3

(watch for URL wrapping)

Priming seems to be limited to just filling the surface-level pump, so
they don't need a lot of priming water at all (subject to the anti-drain
valve in the shaft operating properly)

We've actually got a separate (abandoned) well shaft out back; a pit of at
least 20' deep with square cross-section (sides about 3' wide) - I suspect
that did once house a submerged pump (or at least something operating on
vacuum and not raising water very far). It's so full of junk right now
that I'm not sure how far down it goes :-)

cheers

Jules