Martin C. wrote:
On Mon, 09 Apr 2012 17:10:49 -0700, Bob F wrote:

The recirc pump probably stirs the water in the tank, reducing the
temp at the top, and increasing the heat at the bottom. I imagine it
would show up more the longer the tank is used in a short period.

That's helpful insight!

It must be doing that, because all agree that the water appears hotter
(at least at first) with the recirculation pump turned off.

This morning, I tested the shower, and it took 8 seconds (one
onethousand, two one thousand, etc.) for it to get hot enough to hurt.

So, the recirc pump, in essence only subtracted 8 seconds from the
time- to-hot-water point, but, it also cooled that hot water, and
made a whole lott'a vibratory noise (due to the lousy mounting).

I consider it a win:win with the darn thing unplugged.

I'm just not sure whether to leave the three valves in the open or
closed positions.

If you really aren't going to run the pump at all, close the valves. A better
bet would be to add a time delay relay that would run the pump long enough to
get the hot water to the point of use. You can just push a button in the
bathroom, and have hot water there seconds later without any waste. That's the
way mine works.

A timer set to run when you get up in the morning would give you the advantage
of instant hot water once a day.