I've seen several of these when we had hot water problems.
(new 2 me house, water heater had been recalled for dip tube,
$4 got me a new tube and hot water).

Anyway, I've seen many of these - some that use X10 to turn
them on. All just like Bruce describes. Not a new idea,
not rare, seems like a good idea if you want to keep standing
warm water in your pipes - but just during the morning and
perhaps evening.

Nehmo Sergheyev wrote:
- BruceR -

A better and less wasteful way to do this would be with a Laing
Auto-Circ (http://www.autocirc.com/Autocirc.htm). It easily installs
under the sink in your bathroom and attaches to the hot and cold
....
I've seen hot water recalculating systems like this one

http://www.lainginc.com/howhot.htm

that use a small return pipe. But I never thought of simply sending the
water at the base of the hot water faucet to the cold water line, as in
this "autocirc" system. Ling provides somewhat of a comparison he

http://www.lainginc.com/facts_to_know.htm

The conventional recirculation system needs a return line separate form
the hot and cold supply lines. The "autocirc" system doesn't require a
return line but the cold water at the faucet is mixed a bit with some
hot water, so upon turn-on, it isn't really cold.



I would say if someone is planning instant hot on new construction, then
use the conventional system and run the return line. But it the job is a
retrofit, then the autocirc is the simplest.