T&T: anti-siphon valves

[Randy Pickelmann]

Gil,
You are correct that the N36 is not approved for backflow protection.  But we
don't want a backflow preventer in this case.  The 288A is designed to have
the fluid flowing through it and its design will not work in this application.
Also, I believe that it is not available in 1-1/2" as Larry needs.  The N36 is
plumbed into the line above the water level, generally at the top of a loop.
When the pump shuts off and the pressure is off the system the device opens to
the atmosphere, breaking the siphon.
Regards,
Randy Pickelmann
MORNING STAR
lying at Clearwater, FL
----- Original Message -----
  From: Gil Johnson
  To: rwp_48 at yahoo.com ; TWL
  Sent: Thursday, November 12, 2009 5:04 PM
  Subject: T&T: anti-siphon valves


  Randy said:

  Rather than buying a pre-manufactured anti-siphon valve, make up your own
with a PVC tee and a Watts N-36 vacuum relief valve.  I believe that is the
part number.

  Reply:

  Randy, the N-36 documentation states the following, " Note: Vacuum relief
valves are not designed or approved as back-siphonage backflow preventers. For
protection against back-siphonage install Watts Series 288A vacuum breakers."

  The good news is that the 288A is about $10 cheaper than the N-36.

  Gil