On Fri, 14 Oct 2011 22:31:38 -0500, Ignoramus17081
wrote:

http://igor.chudov.com/misc/ebay/tmp/tmp-8960.jpg

Now go find a "Hand-Off-Auto" switch for the motor starter can, 'Hand'
is for when you switch the unloader valve to Constant Run mode.

Look on the wiring diagrams for the motor starter, they'll show you
where to hook up the pressure switch on the "Auto" loop.

And don't freak on blocking the controls too much with an old
installation, as long as you can get to them in a hurry.

Gunner's right, any Building Inspector walks through and sees this,
they'd shut you down in a heartbeat over safety concerns if this was
new construction. But it isn't - sometimes you just gotta play the
hand you were dealt.

-- Bruce --