Do you -really- think that water coming in at 50 degrees (IINM that is
about normal underground temp) at high velocity, at least that of an
open fixture, is going to pick up much useable heat in 10 ft?
I suspect he is referring to non-flowing conditions. I kind of lost
track here. Does he say that it is in a basement? In my case it is
and the pipe is coated with condensate from the point it enters until
it disappears into the ceiling joists. Temp in my basement is around
65, too cool to sit down there in a t-shirt.
Sure, based on the OP's description and the fact that condensation can
dramatically increase the air-to-pipe thermal conductance by a factor of
100 or more... 2 gpm is 960 Btu/h-F, so warming it 1 F takes 960 Btu/h, ie
1 pint of condensation per hour, about 3 drops per second. I can imagine
that, in continuous use, altho most usage bursts are a lot shorter.
It might make sense to change this pipe to fin-tube vs insulating it :-)
OK -- I am the OP, so let me clarify some points.
1. Yes, the condensation only appears on the first 6 feet or so of the
1" pipe. That pipe runs vertically near the basement wall where the
city supply enters. The 1" pipe is pretty dry after it turns
horizontal and continues to be dry as it branches off to the water
heater and converts down and branches to 1/2" pipe runs for the house
cold water supply.
About 1/3 up the initial vertical 1" pipe run, the 1" pipe bifurcates
to supply the underground sprinkler system. This bifurcated pipe rises
in parallel with the rest of house supply for about 3 ft and then
exits the house. This run also "sweats" heavily.
My initial thought was that the 2 hour runs of the sprinkler may be
primarily responsible for the sweating. However, I have not noticed
significant variability in the condensation between days (and times)
that the sprinkler runs vs. when it doesn't.
Also, the rest of house supply pipe continues to have heavy condensate
for 2-3 feet above where the sprinkler branches.
Also, btw, we heat the hot water with gas and we live in New England.
Finally, last night I insulated the first 10 feet or so of the 1" runs
(except around the valves and water meter), plus the branch to the
We will see what happens (though today is significantly less humid so
it may not give it a good test).
How well sealed is "well sealed"?
Is it enough to buy the Home Chepot middle-grade stuff that comes with
taped edges that you push together?
My sense is that the adhesive tape is enough to keep it on the pipe but not
enough to make a real seal.
Is there stuff that is better to buy or should I cover the seam with
something like duct tape?
In alt.home.repair on Fri, 22 Jul 2005 01:32:04 GMT blueman
If you put it on when the pipe is dry, almost anything will keep the
humid air from touching the pipe after that. No humid air, no
condensation. If part of the pipe is dry, wipe it off with a towel
Personally, I doubt mold or anything will grow on a little dampness on
a copper pipe, but this should prevent any.
If youre still not sure, open part up after 6 months and check it out.
But you have to look right away. The moment you open it up, humid air
might start to condense on the pipe.
If emailing, please let me know whether
or not you are posting the same letter.
Change domain to erols.com, if necessary.
if you leave the pipe uninsulated you will avoid the killer mold in the
insulation problem, which is what you probably heard about on tv news
last year. a spray-on aerosol can foam insulation would ease your mold
worries if you insist on insulation. check with your local building
inspector for requirements and ideas.
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