I am considering adding a hot-water recirculation system to a
residential re-piping job I am planning for my home. Due to the design
of the home (two stories with full basement and full attic), the
re-piping will serve the second floor from an attic manifold (near the
water heater)and the first floor from a basement manifold (17' distant
from the water heater). The water heater is located on the second
I need to know what pump (specs, brand/model, if possible) should be
selected for a 3/4" recirculation loop, where the lowest point of the
loop will be approximately 17' below the water heater return. Also,
where should such a pump be placed, at the top of the loop or bottom,
or does it not matter? Any other considerations?
P.S. Code does not permit second water heater in basement, due to
waterfront flood zone, so that solution is out.
Thanks in advance.
Mine is a TACO Cartridge Circulator Model 006-84 - (very small even
though it is a 28 room home). You might want to put a dial indicating
thermometer on the return line. That will help you set the frequency
and "on" time. You can have multiple returns. The pump is controlled
by the computer on the boiler (in my case a Buderus). Mine runs a few
times each hour for a short period of time and shuts off at night. It
does not matter where you place the pump (since it's a closed system),
but near the water heater is a logical place. Obviously it makes
sense to insulate both hot water feed and return lines.
I've only had one house w/ a hot water recirc pump. It was located
right at the water heater & plumbed into the water heater drain port.
I didn't do the installation, it was "professionally" done whne the
house was built
It was a Grundfo, as far as I know they're somewhat pricey but the one
I had ran 24/7 for the 13 years I owned the place with no problems.
here's a link to a pretty good supplier
the pump in the photo looks just like mine. the install shown has a
timer AND a thermostat..............mine just ran all the time
The site has a general installationscheme but maybe you can ask them
about your special sitiation. IMO the far left hand point of the
sketch looks like the right place for your pump, if you can easily put
pumps work best at (near) the low point of the loop (my w/h was the low
ideally, the sensor for the thermostat should be at the hot water
second choice would at the water returning to the w/h
the return water should be dumped into either the drain port? (as was
done in my install) but my gut tells me it makes better sense to dump
it back via the cold water inlet (a check valve might be a good idea)
but it probably doens't make much difference since my old install
my pump was very low powered, you don't need much plus you want to keep
the electrical cost low.
wrt to pump specs, since it's a closed loop you really don't need much
hp, you're just overcoming the friction losses due to flow
I'd ask them what pump they sugggest, you'll just need to know the loop
length, tube material & sizes.
Do you want those Wirsbo tables?
From what I have seen, the kind of pumps HD, or Lowes has, use a smaller
hose than 3/4". What I have seen gets the pump mounted at the farthest
source for hot water, and the return line from the pump goes back to the hw
tank. The diameter would probably have to do with the distance involved. The
pump runs all the time.
Can you just recirculate from manifold to manifold? Not sure what the
lengths of runs off of the manifold are, but that would make a difference
remove one of the @\'s unless you are a spammer.
"tacker" < firstname.lastname@example.org> wrote in message
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