Flowserve Noble Alloy Ball Valve IOM - Manual (Page 20)

August 22, 2002, Rev. 2 18
PEEK SEATS - CAUTION
PEEK seats require special fitment. Should the seats be installed without checking the seat
preload, the valve may lock up which could possibly over stress the valve stem and damage
it.
Place the seats in the valve, install the ball, and tighten the body nuts without a body seal. Try to
turn the valve using a wrench or the handle on the stem. If the ball does not turn or turns with a
very high effort, disassemble the valve and lap .001" off of the back side (flat side) of one seat and
repeat the procedure.
Repeat the process until the valve turns with moderate torque, lapping one seat and then the other.
PEEK seated valves have a higher torque than TFE seated valves which is normal. Do not make
the ball/seat assembly loose or the valve will not seal. Be sure to install a new body seal when the
seat fitment is complete.