Here is a real world problem: A leaking pool, customer reports 1" per day loss (fiberglass walls, concrete bottom). Customer says water loss mainly
with pump off, heavy air in line. I pressure tested all lines, loss only in return line. Very curious. I replumbed all suction connections at pump,
this cleared up air in pot, but still heavy air returning to pool. Sure seemed like a classic skimmer line leak, except for the clear pot.
I know the answer and will post it and a picture in a few days. Any guesses?
They plumbed a Venturi jet in the return line and the airline cracked or broke.
If it's a Sta Rite Duraglas pump you could be getting air at the strainer pot/volute connection. The original gaskets were paper and tend to leak air
when they get old.
Could also be picking up air at a loose Hayward CL-220 in-line chlorinator lid.
Might also have a leak in the return line, which accounts for the pressure drop when it's pressure tested. I also agree with the cracked venturi air
line theory.
Sounds like a Venturi issue. Still losing?
Chuck is right -the duraglass has a square paper gasket that goes bad and sucks in air- but the air wont be present in the strainer basket.
Sorry, photos didn't work out. The answer is that the leak, and air source, was underground on the return line. The pool builder had used some 1
1/2" spa flex pvc at various places instead of fittings. It had weakened and kinked thereby creating a venturi just past the kink which drew in air
while running. Lost water while off.
Not sure what the attraction to spa flex on pools is but I am running into quite a bit of it. Seems to last 10-15 years before it breaks down and
causes problems. Very popular between bottom drains and skimmers. After 15 years- hello leak detection- goodbye bottom drain!
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Interesting issue with flex. While at the 2013 Spa and Pool show in NJ I came across a vendor specializing in flex pipe. When I told him about
finding crimped flex lines in return lines, skimmers and MDs as well as termite damaged flex lines his comment was, "this product is not designed for
use underground."
Sure seeing a lot of though. Are pool builders that lazy ???
And cheap.... They cut prices, use materials that they KNOW are not suitable for underground use and then do poor site prep and refill as they know that for the short run the system will work just fine.... at least until the check clears then they wash their hands of the job. Sometimes there are no issues but other times there are. That's where we come in
I do most repairs after the detection is performed. We offer a life time warranty on skimmers and all pipe repairs. In my experience flex pvc has come in quite handy to make odd angles work as opposed to making swing joints, especially on jet repairs. I use it only when there are screwed up circumstances but should I worry?
Copper corrodes
PVC cracks
Rubber rots
The point is that everything will eventually return to its basic elements. Some things take longer than others.
Water is a universal solvent...(see Grand Canyon)
Funny Sidewolf, I use the Grand Canyon analogy almost daily. Well said brotha