keith wrote:
As I re-plumb my house, I have added a recirculation pump and
extra return line. If I'm going to want hot water, I push a
button, and 30 seconds later (or less) I can turn on the hot and
have it hot in 2 seconds.

At the cost of twice as much wasted hot water. I understand how a
recirculation pump works. How's this magic manifold work?

At the cost of no wasted hot water, in fact no wasted $.017/gallon
water. I don't have a clue what the "magic manifold" you speak of
is.

When you turn off the hot water you now have twice as much "waste"
hot water in the lines. Read the thread.

No, I don't. The pump turns off before the return pipe is filled.
And I haven't dumped the water in the pipe down the drain waiting
for it to get hot. Try thinking.

Baloney. The water won't be up to temperature that quickly. Truy not
to make crap up.

I only did it. That is the result. Where does your expert opinion come from?

It works just like running the water to get hot water, but the water goes back
to the heater instead of down the drain. It isn't rocket science.