DD_BobK wrote:
On Apr 18, 11:03 pm, Brent beemdoub...@Use-Author-Supplied-
Address.invalid wrote:
I'm curious why they paint all the white 2-inch PVC pool pump area
pipes flat black?

On Friday, I put a new pool pump motor in but forgot to open all the
Jandy valves so the pipes overheated, expanded, and blew up in
places (a 1.5 HP motor is strong!).

Anyway, my 2 inch outside diameter PVC pipe from Home Depot earlier
today now stands off as bright white while the rest of the pipes re
painted flat black.

No big deal but I was wondering WHY they paint the PVC pool pipes
black and if it's a good enough reason for me to follow suit on my
2-foot section of repair pipes.

The three reasons I can think of don't seem to hold water:
- heat retention? (c'mon ... how much heat will black retain over
white on a few pipes that are in the open sun?)
- sunlight damage? (maybe ... but then why don't they just sell pool
pipes that have paint on them already)
- asthetics? (c'mon ... can black matter versus white)

Any other reason for the flat black pool pipe paint?



Paint is for UV protection of the white PVC (not sunlight resistant).
btw, pre-painted PVC would be a PITA to solvent weld

Could you clarify this sentence?

"On Friday, I put a new pool pump motor in but forgot to
open all the Jandy
valves so the pipes overheated, expanded, and blew up in places (a 1.5
HP
motor is strong!). "

What caused what to overheat? Did the system have water in it?

The horsepower of the pump is pretty much meaningless with respect to
"blowing up" pipes.

It's the amount of head (pressure) generated that stresses the piping.

A 1.5 hp pump / motor can either deliver high flow / low head or low
flow / high head or something in between; depends on the pump
design / curve.
Most pool pumps would be hard pressed to get anywhere near the
allowable maximum pressure for PVC piping.

A pump running with no flow through heats up the water in it quickly due to the
internal friction. The pipe gets warm and softens. The pressure blows it out.

On Mon, 19 Apr 2010 07:45:13 -0700, Bob F wrote:

A pump running with no flow through heats up the water in it quickly due to the
internal friction. The pipe gets warm and softens. The pressure blows it out.

That's exactly what happened!

The pump ran but couldn't push any water past the shutoff (the jandy
shutoff leaked profusely but not enough).

Then the threads must have softened and the pipes heated up because a
post-mortem analysis showed the threaded pipes melted in a V shape (hard to
explain) such that they just blew right out of the motor.

When I tried to connect 2" OD PVC to the cut edge of the pipe run, I found
that the 2 inches had swelled greatly (almost a sixteenth of an inch or so
.... way more than can be sanded).

So I just cut off MORE pipe (no big deal); but I was wondering about the
paint.