"Derek Broughton" wrote in message
...
Harry Chickpea wrote:

...
the same Nickie that pooh-poohed the idea of
inexpensively preheating water for a domestic water heater via the
simple expedient of placing a 4" pipe underneath and along the
ridgeline of a roof. IIRC, his comments were along the lines of what
if it leaks, what if it freezes? Yet, he has no comment or solution
for the same questions about his own Nickie special design.

And your problem is??? In a stand-alone greenhouse, you don't have a
serious problem if it springs a leak. If it's in your house, you sure
do.

It isn't my problem. As I pointed out to Nick at the time, a 4" pipe
contains enough thermal mass, and the location is inherently warmer
than the rest of the attic, to preclude freezing in all but the most
extreme climates, and allowing a small cushion of air at the top for
expansion would resolve the issue even if it did freeze. The pipe
would be no more or less likely to spring a leak than any other pipe.
I suggest that you and Nick might want to remember that people have
plumbing and even gasp! bathtubs on the second floors of their
homes, and condos and apartments and office buildings have plumbing
that reaches to the sky. Somehow, they survive.

What do you consider "the most extreme climates"? Most of the US, and
practically all of Canada, are subject to regular conditions _well_ under
freezing, and we do NOT have plumbing along the ridgelines of our roofs.
To prevent ice-damming, attics are kept as cold as possible, and all
plumbing is kept below the insulation. If your attic is warm enough in
winter to prevent a pipe freezing, you're wasting too much energy.

A vented attic, in which the only function of the rood is to keep off the
house, nothing else.

I haven't a clue (and don't really care) if Nick's idea is sound, but his
objection to a 4" pipe under the ridgeline of a roof certainly is.

Only in Canada type of climates.