| PROPER INSTALLATION PROCEDURE |  | IMPROPER TECHNIQUES |
|
Pipework opened to allow free valve entry with the disc in a semi-closed position.  | Pipework not spread sufficiently - could tear rubber seat. Disc in open position will hit flange and score disc edge.  |
Valve in semi-closed position to (1) protect disc edge, (2) reduce rubber interference during installation and start-up, and (3) help reduce initial torque build-up.  | Disc as shown in fully closed position causes seat distortion. When flanges are drawn up, rubber will close around disc edge creating excessive torque in initial operation.  |
Disc should be turned to full open position after flange alignment and before evenly pulling up flange bolts.  | Incorrect pipe alignment will cause interference between disc edge and flange face creating leakage and excessive torque for opening valve. |