Tank Tees
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      1. Boshart Knowledge Base
      2. Tank Tees

      Do you have the white Teflon flat washer / gaskets for the older style union tank tees?

      Yes, although we do not use the term "TEFLON" as it is an infringement on a registered trademark of Dupont.  For this reason, we refer to the washers as P.T.F.E., which stands for the actual material name polytetrafluoroethylene.

      The part numbers are 07PT-TW-10 (1” tees) and 07PT-TW-12 (1-1/4” tees). The transition from the P.T.F.E. washers to the current O-Ring seal occurred back in 2014. It was a running change under the same part number(s) which has caused some confusion.

      07PT-TW-10        P.T.F.E. WASHER FOR ALL 1" UNION TANK TEES

      Used in older model UNION TEES prior to the change to an O-Ring seal in July of 2014.

      Part No’s: 07ST-25S-2U, 07ST-8-2U, 07ST-25-2U, & 07ST-14X1-2U.

      07PT-TW-12        P.T.F.E. WASHER FOR ALL 1-1/4" UNION TANK TEES

      Used in older model UNION TEES prior to the change to an O-Ring seal in July of 2014.

      Part No’s: 07ST-13S-2U & 07ST-13-2U.

      The washer/gasket dimensions are detailed below.

      Why was the design changed from the P.T.F.E. gasket to the O-Ring union seal?

      While the durable P.T.F.E. (polytetrafluoroethylene) washer provided an excellent seal, the change to the O-Ring seal was made for the two reasons below.

      #1 - Significant changes in installation practices from rigid piping to PEX piping from the tee to the household plumbing and the use of poly pipe or braided hose from the well or submersible pump resulted in the tank tee head going out of alignment due to the slippery characteristics of the P.T.F.E. gasket. The tank tee heads tended to swivel if the line connection piping was not properly supported. The O-Ring seal provides a gripping action which eliminates any swiveling at the union, holding the tank tee head in perfect alignment.

      #2 - The flat washer type PTFE gaskets were more likely to fallout of the union nut and get lost. The new O-Ring design has the O-ring secured, either in a precision machined groove (Stainless Steel Tank Tees) or over the casting (NL Brass Tank Tees). These systems reduce the risk of the seal falling out.