In article ,
"Roger Long" wrote:

I've now done what I should have first thing, made some calculations
of my sump size and hose volume. I want generous pumping capacity
which means 1 1/8" hose to avoid head losses in the long runs. The
volume of hose divided by the area of my sump is greater than the ON /
OFF range of any switch I have been able to locate.

I don't want to use check valves because a little bit of fluff sucked
into one could set up the endless pumping cycle. Also, if the water
drained back from the check valve, the line would essentially be
airbound.

Our check valve worked just fine for about a decade. The primary reason
I put it in was because our stern wave sometimes comes halfway up our
transom and I don't like the idea that the bilge pump hose could lead
that water into the boat.

One trick that could change the mix: Add a vacuum break elbow close to
the pump, but above the moving waterline

--
Jere Lull
Xan-a-Deux ('73 Tanzer 28 #4 out of Tolchester, MD)
Xan's Pages: http://members.dca.net/jerelull/X-Main.html
Our BVI FAQs (290+ pics) http://homepage.mac.com/jerelull/BVI/