On Sun, 07 Aug 2016 23:41:38 -0400, FromTheRafters wrote:
The answer to the original question is easy. The CW pipe feeding the HW
tank warms up for a good distance both up & downstream from the "T"
feeding the HW tank.
The pipe further downstream near the faucet is closer to ambient
temperature. This is the first water to exit the faucet. It is followed
by the water that was resting in the pipe near the HW tank which is
warmer. That is followed by fresh water that just came in from the pipe
undergroung feeding the house. Usually this will be cooler than the
This does remind me of something from my days in college. There were a
few of us renting an apartment at a place everyone called "Cockroach
Towers" on the 9th floor.
If you turned on the cold water and let it run, it would normally never
get very cold at all. Basically, by the time the water got to our floor,
it would be at about ambient temperature of the air in the riser. In the
summer it would be only slightly cooler than tepid no matter how long
the faucet had been open.
It was under pretty good pressure though. We were close to the water
tower, and it took all the strength of one thumb covering the other to
staunch the flow.
I discovered this when I was experimenting with how to target anyone
passing into the kitchen with a directed dousing. When I tried to
increase the pressure by opening the hot water control, I noticed
something truly remarkable:
With both taps open, if a stream was allowed to flow under pressure
(i.e. partly blocked; not free-flowing), then completely stopped off for
a few seconds, and then released a bit to let out a high pressure
stream, after a few seconds of lukewarm water, there was a blast of
frigid teeth-chattering almost ice-cold water, followed again by the
lukewarm water. We all soon became adept at repeatedly blocking,
releasing, and collecting the cold water. An average size drinking glass
needed about 4 or 5 cycles.
Nobody ever figured out the mechanism for the cooling. Each apartment
had its own 10 gallon hot water tank, which I believe had a 'vacuum
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