On Oct 7, 5:44*pm, "Dave, I can't do that"
wrote:
Hi,

I have two separate runs of hot water in my house and to use two of
these commercial units would cost almost 500-bucks.

http://www.lowes.com/lowes/lkn?actio...ductId=77814-1....

I am thinking one of these and a couple of temp sensors for on and
off.

http://www.harborfreight.com/cpi/cta...temnumber=1479

I have emailed HF asking for the max operating pressure as my well
pump maxes out at 50 psi.

Practical comments and suggestions please?

Dave

Looks like the way this one works, when the timer is sets the unit to
'on', the motor always runs and creates a pressure differential
between the hot line and the cold line (it pressurizes the hot line
relative to the cold line).

Then, the sensor-bypass thing is a thermostatic valve that just lets
water pass from hot to cold as long as the 'hot' side is below some
set temperature.

Neat! Wastes some energy in the pump, and having the hot line always
'hot' wastes some energy too.That's arguable if the pipe is in a space
you'd like to heat, since the wasted heat will just go into a space
you're trying to heat anyway.

It looks like as long as you have only one hot water heater, you only
need one pump, and can add the bypass valve to multiple faucets. If
your hot line from the heater branches, you put the pump before the
branch, and then install a bypass valve at the end of each branch.

If I was going to build something, I'd prefer the pump that sits at
the end of the line, and only activates when you push a button. The
pump runs until 'hot' water shows up. Hit the button on your way in,
when you're ready to wash up, the water's warm. If you're heading in
to just use the hot water, you still have to wait though...


Anyway, the pump you linked to looks like serious overkill- you want
something that can tolerate no flow ( a blocked pipe).



Dave