Scott wrote:
After much wailing and gnashing of teeth today, and an expensive lesson in
just how much I don't know about swamp coolers, I replaced my ancient swamp
cooler's bleed line with a purge pump. I've never seen one in action
before.

Is it normal for the purge pump to run the pan completely empty, to the
point of leaving both pumps running dry for a few minutes? It seems
excessive to me. I figure I'd want to leave just enough water in the pan to
keep the pad pump going.

I added a clamp to the purge line to restrict the water flow. Thinking
about it now, that's probably a mistake. The correct move might be to
elevate the purge pump, maybe 1/4" or so, just enough so that the pad pump
doesn't run dry.

I know I'm nitpicking over details that probably don't matter. I just want
to understand how this jury-rigged pile of rusty sheet metal is really
supposed to work.

Thanks,
-Scott

Instructions for this model says it leaves "less than 1/2" of water"

http://www.kennspenns.com/coolerpart...tallation.html