On Jun 18, 9:17 pm, William Underhill wrote:
randyn wrote:
A few months ago, I had a slab leak in the cold water supply to my
kitchen sink. The plumber rerouted the line through the attic using
PEX, insulated with a black foam sleeve/wrapper.

Now that summer is near, I am finding that, in the afternoon (if the
sun is out and the outdoor temperature is in the 80s or above), the
cold water from my kitchen sink tap is warm-to-hot for 30 seconds or
more before it cools down. The kitchen tap is on the other side of the
house from the cold water manifold, so it is a long run of pipe. I
measured the temperature at the tap with a kitchen thermometer today--
it was 130 deg F for 10 seconds or so, which seems really out of line.
I haven't seen this problem mentioned in other postings to this group
concerning attic routing of water supply lines.

Is this normal for attic-routed cold water supply lines in a hot
climate? I have a hard time believing that the water could pick up so
much heat. My attic has passive ventilation, with no soffit vents.
Would improving attic ventilation result in a big improvement? Or is
the plumbing work defective somehow?

Thanks

Hm - I'd say the black foam is absorbing ambient heat in the attic. You
say it's a warm climate; is the attic air temp warm to very warm during
the day? If so, you may have to consider active ventilation and/or
insulation.

Yours aye,
W. Underhill

I should have mentioned earlier that I'm in Lubbock, Texas, where
today the temp peaked at 99.6, with a cloudless sky. The attic is
quite hot on days like this, though I haven't measured the attic
temperature. And it isn't even summer yet!

thanks,
Randy Norwood