Instruction Manual
D103302X012
A81 Valve
January 2011
4
Description
The A81 rotary valve with FieldQ rack‐and‐pinion actuator offers automated on‐off, quarter‐turn performance. FieldQ
is available in spring‐return and double‐acting piston designs.
The valve body meets PN 10 through PN 40, CL150, and CL300 ratings. Face‐to‐face and raised‐face dimensions meet
EN 593, API 609, and MSS‐SP68 standards. Retainer clips provide for versatility to mount and align the same wafer
style valve body in different piping configurations (ASME and EN ratings).
The A81 rotary valve features an eccentrically‐mounted disk with either soft or metal seal, providing capability for
enhanced shutoff. The interchangeable sealing technology allows for the same valve body to accept both soft and
metal seals.
Installation
Key numbers in this procedure are shown in figure 9 unless otherwise indicated.
WARNING
Always wear protective gloves, clothing and eyewear when performing any installation operations to avoid personal injury.
To avoid personal injury or property damage resulting from the bursting of pressure retaining parts, be certain the service
conditions do not exceed either the valve body rating or the flange joint rating, or other limits given in table 1 or on the
nameplate. Use pressure‐relieving or pressure‐limiting devices to prevent the service conditions from exceeding these
limits.
If installing into an existing application, also refer to the WARNING at the beginning of the Maintenance section on page 8
in this manual.
CAUTION
The valve configuration and construction materials were selected to meet particular pressure, temperature, pressure drop,
and controlled fluid conditions specified in the customer's order. Because some valve body/trim material combinations are
limited in their pressure drop and temperature range capabilities, do not apply any other conditions to the valve without
first contacting your Emerson Process Management sales office.
The maximum allowable inlet pressures for steel and stainless steel valve bodies are consistent with the
pressure‐temperature ratings shown in table 1, except where further limited by the trim and packing material
temperature capabilities given in table 3. Valves are also available in CW2M and M35‐2 valve body materials that are
not listed in EN 12516‐1 or ASME B16.34. Valve bodies constructed of these materials mate with EN and ASME flanges
but are not included in EN or ASME pressure‐temperature ratings and must
not
be installed in systems requiring
conformance to EN or ASME standards. Maximum allowable inlet pressures for A81 valve bodies made of CW2M or
M35‐2 construction materials are shown in table 4.
1. Install a three‐valve bypass around the control valve assembly if continuous operation is necessary during
inspection and maintenance of the valve body.
2. Inspect the valve body to be certain it is free of foreign material.
3. The valve is normally shipped as part of a control valve assembly, with an actuator mounted on the valve body.
If the valve body and actuator have been purchased separately or if the actuator has been removed for maintenance,
mount the actuator, and adjust actuator travel before inserting the valve body into the line. This is necessary due to
