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PROPRIETARY BOOKLET OF VALVEWORKS USA. DO NOT REPRODUCE WITHOUT EXPLICIT PERMISSION.
Page 18
WARNING:
1.
The backseat is only intended to be used in an emergency situation to stop packing
leakage.
2.
One of the features of the back seat is to change the stem packing under pressure on well,
even though it is not promoted. It is always recommended that the valve be removed from
service before packing is changed unless an emergency. If the packing has to be changed
while under pressure, a second pressure barrier needs to be used to help isolate the
pressure.
3.
By backseating the valve it is possible the gate will not seal the bore line.
2. Loosen the bearing cap using a
pipe wrench.
(Approximately 3 1/2 - 4 turns)
1. Turn the handwheel counter-
clockwise until the gate is in the
open position.
(In case of Direct Operating gate)
3. Turn the handwheel clockwise
until the gate is in the closed
position.
BACK SEATING PROCEDURE
4. Over run the closed position such
that the gate hits the bottom and
rises the stem; which jams the back
seat area.
MODEL FC SERVICE AND OPERATION MANUAL
