Flowserve Edward Cast Steel Bolted Bonnet Valves - Manual (Page 13)

13
Flow Control Division
Edward Valves
Disassembly Procedures
(cont.)
5. Turn the actuator handwheel in a direc-
tion to close the valve, thus unscrewing
the actuator from the stem. Try to keep
the weight on the hoist as the hand-
wheel is turned to prevent damage to
the stem threads.
6. With the hoist, lift the actuator clear of
the stem and place down on clean area
for further disassembly, if required.
ELECTRIC ACTUATOR LIMIT
SWITCH AND TORQUE SWITCH
SETTING PROCEDURES
The following procedures are intended as
a general guide for setting limit and torque
switches on electric actuators. For specific
instructions, refer to the appropriate actua-
tor instruction manual or consult the actua-
tor manufacturer.
Geared Limit Switch
When mounting or re-mounting an electric
actuator, the geared limit switch must be
reset as follows:
1. Make certain the electric current is off.
2. Open valve by hand until the stem
strikes the backseat.
3. Mark the stem and reclose approximate-
ly 1/8” to allow for coast of the moving
parts.
4. With the valve in this position, set the
opening limit switch as outlined in the
actuator instruction manual.
5. Connect the electric current and check
this setting as follows:
a. Run the valve to mid-position by
hand.
b. Press the “open” push button-make
sure the valve is moving in the
“open” direction.
c. Allow the limit switch to stop the
motor.
d. After the motor has stopped, turn the
valve by hand to make certain there
is sufficient clearance between the
position at which the valve stem
comes to rest and the valve backseat.
6. To set the position for operation of the
indicating light, make sure the torque
switch is properly wired into the closing
circuit and run the valve to the closed
position. Back the valve off the seat to
the desired position and set the “closed”
light using the procedure outlined by the
actuator manufacturer.
Torque switch
The torque switch is set during factory
assembly to seat the valve against the
specified unbalanced pressure and to
protect the valve from excessive seating
forces. Should it become necessary to
change the torque switch setting for any
reason, the local Edward Valves represen-
tative should be contacted for instructions.