On Sep 18, 3:29*pm, wrote:
On Sep 18, 11:52*am, wrote:

On Fri, 18 Sep 2009 07:33:31 -0700 (PDT), harry k

wrote:
Yes, his system is operating correctly. *Oddly, although the standard
is 2psi below cut-in, some tanks (and mine included) say 'same as cut-
in'. *I cannot understand why the pump would ever start with pre-
charge at or higher than cut-in. *I set mine to 2 psi below.

The tank pressure only shows up at the pump switch when there is some
water in the bladder to transfer it. The pressure drops to zero on the
water side when the bladder is empty.

And even if there is some water in it, say a couple gallons, the
pressure is going to be lower than the pressure in the bladder. * The
pressure difference is made up by the tension on the bladder as it
stretches. * *As you pointed out, with an empty tank the gauge will
read zero. * As you start to pump water into it, the water pressure
will gradually rise. *It's not going to be instantly equal to the
pressure that is pre-loaded into the bladder.

1. The bladder 'tension' will not approach cut-off psi. Pressure in
both sides will be, for practical purposes, identical. Not sure but I
believe the bladder is flacid when the tank is empty (fastened at the
bottom, not top). Some of them are replacable without dissembling the
tank.

2. The gauge will never reach zero if there is a little bit of water
in it.

3. The reason the pressure drops to zero (I overlooked that) is that
the bladder blocks the tank exit.

Harry K