Model A31A
5
D
The valve configuration and
construction materials are selected to
meet particular pressure, temperature,
pressure drop, and controlled fluid
conditions. Some body/trim material
combinations are limited in their pres-
sure drop and temperature range capa-
bilities. Do not apply any other condi-
tions to the valve without first
contacting your Fisher Controls sales
office or sales representative.
1. Isolate the control valve from the line pressure, re-
lease pressure from both sides of the valve body, and
drain the process media from both sides of the valve.
If using a power actuator, shut off all pressure lines to
the power actuator, release pressure from the actua-
tor, and disconnect the pressure lines from the actua-
tor. Use lock-out procedures to be sure that the above
measures stay in effect while you are work on the
equipment.
See the WARNING at the beginning of the
Mainte-
nance section for more information before removing
the valve from the pipeline.
2. Install a three-valve bypass around the control
valve assembly if continuous operation is necessary
during inspection and maintenance of the valve.
3. Inspect the valve to be certain that it is free of for-
eign material.
4. Be certain that adjacent pipelines are free of any
foreign material, such as pipe scale or welding slag,
that could damage the valve sealing surfaces.
CAUTION
Damage to the disk will occur if any pipe
flanges or piping connected to the valve
interfere with the disk rotation path. If
piping flange has a smaller inner diame-
ter than specified for schedule 80 pip-
ing, measure carefully to be certain the
disk rotates without interference before
placing the valve into operation. Mini-
mum inside diameters for flanges or
pipe mating with valves are shown in
tables 3 and 4.
Valve Orientation
The valve can be installed in any orientation however,
it is recommended that the valve drive shaft be hori-
zontal and the actuator vertical as shown in figure 4.
Install the valve with the high-pressure shutoff side in
the direction noted by the flow arrow for proper instal-
lation, and see figure 4 for more information.
Before Installing the Valve
WARNING
The edges of a rotating valve disk (key
2, figure 9) close with a shearing, cut-
ting motion. To avoid personal injury,
keep hands, tools, and other objects
away from the disk while stroking the
valve.
If the Model A31A valve is equipped with
a fail-open actuator, cycle the valve into
the fully closed position. Ensure the
valve can not open during installation
by using travel stops, a manual actua-
tor, a constant supply pressure to the
pneumatic actuator, or other steps as
necessary.
CAUTION
When using an actuator, the actuator
travel stop (or actuator travel, for actua-
tors without adjustable stops) must be
adjusted so the disk stop in the valve
does not absorb the output of the actua-
tor. Failure to limit the actuator travel as
described in the
Adjusting the Actuator
Travel Stops or Travel steps can result
in damage to the valve, shaft(s), or other
valve components.
A Fisher Controls Model A31A valve is normally
shipped as part of an assembly with an actuator and
other accessories such as a valve positioner. If the
valve and actuator have been purchased separately or
if the actuator has been removed for maintenance,
properly mount the actuator and adjust valve/actuator
travel and all travel stops before inserting the valve
into the line.
CAUTION
Damage to the disk will occur if any pipe
flanges or piping connected to the valve
interfere with the disk rotation path. Be
certain to align the valve accurately to
avoid contact between the disk (key 2)
and the flanges.
