"Bob" wrote in message

In an attic installation, how much performance is lost with an uphill
pipe run?

Certainly you are working against the force of gravity and heavier objects
will stall going up a upward vertical intake instead of being helped along a
downward one. Who hasn't had to work a vacuum hose like a snake swallowing a
rat to get a stone or some other heavy object to move along?

While I do distinctly recall some discussion of how water lift (the
traditional method of measuring suction) was lower in "up to the attic and
down again designs," that could easily be because of the longer pipe runs
and the potentially greater number of leaks.


When I first looked into CV's I had to learn a whole new terminology to
compare units and estimate "suckiness" (in more than one dimension!). The
first oddball term was air watts, which at first sounds useful in evaluating
air guitars but is really an attempt to express suction power at different
nozzle diameters. Some CV accessories are air powered and put an extra load
on the system, hence the attempt by manufacturers to express the ability to
perform work with the air flow, giving us air watts. Anyway, what I
discovered was that a properly plumbed and sized CV system has more than
enough suction power to work from any location in the house.

I won't be mounting mine in that attic for reasons other than any possible
slight performance loss. Attic installations are not fun to service in
general, but the incredible heat genned in many attics leads to summertime
failures where you may encounter near-lethal heat, high humidity, wasps,
squirrels, bees and yes even ("who would hang all these teeny little black
bowties
upside down inside this closet?") BATS!!! That's why I would avoid the
attic and do.

But many folks are fine with attic installs, and since the installation
manual:

http://www.merchandisemecca.net/haydeninstallguide.pdf

(No affiliation, no recommendation, for all I know the worst virus in the
world will infest your machine upon visiting the site - use at your own
risk!!!!)

shows layouts for older homes where a single pipe ascends to the attic and
then comes down from above - an up and over design familiar to old house
rehabbers. So obviously it's not enough of a hit to be a serious issue. It
may be a blessing in disguise in that big heavy stuff is *less* likely to
get sucked into the main intake run because it would never rise high enough
to reach the attic run and might just fall out of the outlet at next
operation.

A much more serious set of performance robbing problems are leaky outlet
cover plates, poorly thought out pipe runs, very sharp bends, bad solvent
welds and burrs left on the inside of the pipe that catch the tiniest hairs
at first that eventually turn into full blown clogs. All of the branches
need to be designed with gradual sweeps and not elbows (except right before
the main intake on the motor unit) so that longish debris doesn't get forced
to make too sharp a turn and clog.

I thought CV installation was going to be just like drain pipe installation
but it was quite a bit different. All piping had to be cut with a tubing
cutter and then sanded out to make sure there were no rough edges. Since
it's a pressurized system, I didn't have to pay attention to pipe slope.
Vacuum piping has a much thinner wall and lighter couplings than similar
sized drain pipe which surprised me. I thought that they both used the same
type of pipe but I was wrong. When my unit is sucking sawdust generated by
the radial arm saw, no one can do any vacuuming elsewhere because the vacuum
level is too low if more than one outlet is active. I could get around that
if I were willing to add a second motor unit the way water heaters are
ganged together. Not likely!

Even during operation, I never run the hose without some sort of narrower
nozzle or attachment on the end to keep as many nasty things as I can from
clogging the hose (most of the time) or the pipe (much larger diameter than
the hose, so happens very rarely).

As far as bang for the buck, aside from the noisy motor unit, CV is great.
No motor whine in the same room you're working in, no blown-up dust swirling
around your head from the output air. That's all piped outside along with a
few million dust mites and the carcasses of their fallen brothers.

--
Bobby G.