Parts Ordering - Fisher D4 Instruction Manual

Instruction Manual
D103042X012
When replacing O‐rings and bushings, be sure the O‐ring or bushing groove is clean and undamaged. Using a
general purpose lubricant (key 49), lubricate all bushings and O‐rings and the threads of parts that have to pass
through the bushings and O‐rings.
CAUTION
The threads on factory‐produced valve stems have been specially machined to avoid O‐ring, bushing, or packing damage
during trim maintenance. Use of other than a factory‐produced valve stem may result in early stem O‐ring, bushing, and
packing failure.
Note
Do not lubricate cap screws (key 38) before inserting them in the following procedure.
2. Place the hammer nut and spring pins on the bonnet, if removed. Install the casing O‐ring (key 18), the stem O‐ring
(key 19), and the bonnet bushing (key 20). Position the lower casing (key 39) on the bonnet. Insert the
nonlubricated cap screws (key 38), and torque to 49 NSm (36 lbfSft).
3. Assemble the diaphragm plate assembly. Place the patterned side of the diaphragm (key 15) against the diaphragm
plate (key 40). Be sure to turn the diaphragm washer (key 41) so that the side that is beveled on the inside diameter
is against the O‐ring (key 25). Also, make sure that it is assembled for installation with the diaphragm on the loading
pressure side and the lockwasher (key 43) and diaphragm washer (key 41) are on the upper side.
WARNING
The spring pins must always be in place during valve operation. They provide a safeguard against injury when the unit is
being disassembled.
4. Fasten the diaphragm and diaphragm plate assembly on the stem with hex nuts (key 42). Place the diaphragm and
diaphragm plate, and stem assembly into the lower casing and bonnet. Install the travel indicator (key 32) on the
stem as the bottom of the stem enters the yoke window.
5. Screw the adjusting stem (key 31) onto the stem (key 47) and secure the cotter pin (key 36). Make sure the bushing
and O‐ring are in place in the upper casing.
CAUTION
Over‐tightening the diaphragm casing cap screws and nuts (keys 45 and 46) can damage the diaphragm. Do not exceed 27
NSm (20 lbfSft) torque.
6. Position the upper casing (key 23) on the lower casing (key 39). Insert the cap screws (key 45) and tighten the hex
nuts (key 46). Torque the casing cap screws evenly to 27 NSm (20 lbfSft) using a crisscross pattern.
7. Replace the spring (key 30), spring seat (key 29), and adjusting stem nut (key 44) over the adjusting stem. Replace
the spring case assembly (key 27).
8. Adjust the initial spring set per the Spring Adjustment section in this manual.

Parts Ordering

Each D4 control valve is assigned a serial number, which can be found on the nameplate. Refer to the number when
contacting your Emerson Process Management sales office for assistance or when ordering replacement parts.
D4 Valve
July 2015
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