7
On all other model of actuators:
1.
Record the current adjusting screw setting relative to the reference scale.
2.
Set the adjustment screw to approximately “5” on the reference scale.
3.
Remove the sensing bulb from the Thermowell or process.
4.
Subject the sensing bulb alternately to temperatures near the high and low limits of the nominal range of the
instrument. This nominal range can be found on a tombstone shaped aluminum tag hanging from the tubing.
5.
If the stem motion up and down of over a ¼” is observed then the actuator is good.
6.
If no motion is seen, remove the actuator from the valve body. See section on “Removing Valve Body
Assembly”.
7.
Repeat steps 2-5
8.
If no motion is seen, then the actuator is dead and needs to be replaced.
a)
Obtain a replacement actuator and install onto the existing valve.
(See section on “Replacing Valve Body Assembly”)
b)
Finish re-installation of actuator and set adjusting screw to previously recorded reference number.
c)
Restart as if a new installation per this instruction manual.
d)
If motion is seen, the actuator is good. Set adjusting screw back to recorded reference mark and then
inspect the valve for proper operation.
Inspecting Valve Body Assembly
1.
Remove the Valve Body Assembly from the actuator. (See section on “Removing Valve Body Assembly”)
2.
By gloved hand, alternately push the valve stem down and pull up. There should be at least ¼” of motion.
3.
If no motion is observed, the valve is jammed.
a)
Remove valve from line and inspect for debris caught between the valve seat and the valve plug
preventing the valve from closing. Disassembly of the valve may be required. (See section on
“Reversing Valve Action”)
b)
If debris is successfully removed and valve reassembled, repeat step 2.
c)
If no motion is seen, obtain a new valve.
d)
If valve is now working, or new valve obtained, reassemble valve to actuator. (See section on “Replacing
Valve Body Assembly”)
REPAIRING VALVE BODY ASSEMBLY
Removing Valve Body Assembly
1.
Allow the sensing bulb on the actuator to cool to the bottom of the nominal range. Artificially
cool with ice if necessary.
2.
Record the current actuator adjusting screw setting relative to the reference scale.
3.
Turn the actuator adjusting screw in (up) to reference number 8.
4.
Hold the hexagonal actuator stem with a 5/16” wrench. With a 3/8” wrench, hold the two stem locknuts as a
wrench flat and loosen the valve stem from the hexagonal actuator stem.
DO NOT DIRECTLY GRIP THE ROUND POLISHED PORTION OF THE VALVE STEM.
5.
Remove the Bonnet Nut holding the actuator to the valve with a 1-½” wrench.
6.
Unscrew the valve stem from the actuator stem by turning the entire valve body. If the valve body is still in-
line, then unscrew by gently turning the valve stem, gripping it ONLY by the 3/8” hex nuts. Do not directly
grip the round polished portion of the valve stem.
a.
Make sure the valve plug is off of the valve seat while turning valve stem to prevent galling of the
seating surface.
b.
The above instructions will assure a heating valve plug is off of the seat. On a cooling valve it may
not be possible to lower the valve plug off of the seat. If it is not possible to make sure the valve is
open, then while holding the valve stem stationary gently turn the actuator stem to unscrew.
7.
The Valve and Actuator may now be separated.
