I have a 20+ year old Tahitian sand filter which has worked reliably.
The valve's "web" gasket has begun to leak [I get an extremely slight
leakage on the backwash side] but, as far as I can tell, is no longer
available for replacement.
As a result of the leakage, the system no longer holds a vacuum overnight
and pumps air for a few minutes every morning.
I am now getting an occassional small amount of sand injected in the pool
just after startup, and usually some with the backwash if I haven't been
running the pool first.
There are replacement laterals available but I'm thinking that the sand may
be caused by cavitation when all the air is pumped at startup.
I hestitate to spend the time checking out the laterals if cavitation is the
cause due to the web gasket.
Am I on the right track?
Any suggestions on fixing the web gasket?
Thank you.
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try:
http://www.aqua-man.com/schematic.asp?heading_num=1777

Good source but not much joy as the site says the valve parts are obsolete
and suggests a complete replacement valve for $182.00.
I almost wouldn't mind the price if I were a bit more confident that the
sand discharge is caused by the worn valve gasket as opposed to a cracked
[and possibly irreplaceable] lateral.
I shall ponder some more.
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