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the cover bolt holes with no stretching
of the diaphragm. The compressor
extends 0.72” from the bonnet face in
this relaxed position, reference p. 10
for a view of the compressor position.
Re-assembly is the reverse of the
above, use Blue Loctite #242 on the
spindle nut. See Table 1 for fastener
torques.
3.6.4 Spindle O-Ring Replacement
(All Sizes)
3.6.4.1 Disconnect air lines, remove actuator
assembly from valve body and disman-
tle actuator following instructions
above for removing actuator
diaphragm.
3.6.4.2 Withdraw valve diaphragm, compres-
sor and spindle assembly from the
bonnet.
3.6.4.3 Remove old o-rings, taking care not to
damage machined surfaces. Lubricate
new o-rings per Section 3.4 and install
in grooves. Reassemble reversing the
above instructions. Care must be used
on the Bio-Tek to align the compressor
T-slot with molded tabs in lower cover.
3.7 Reverse Acting
(REMOVE ALL LINE PRESSURE)
3.7.1 Valve Diaphragm Replacement
3.7.1.1 Load the bottom chamber of the actu-
ator with sufficient air to partially open
valve. This will ease the spring tension
holding the valve diaphragm to the
body weir.
3.7.1.2 Remove the bonnet bolts. Lift actuator
assembly from valve body. Release air
and disconnect air line.
3.7.1.3 Unscrew diaphragm from compressor
by turning counterclockwise.
3.7.1.4 For PTFE assemblies only: Replace back-
ing cushion and PTFE diaphragm.
Note: To engage the threads of the
diaphragm stud invert the PTFE
diaphragm. To invert the diaphragm,
press on the center of the
diaphragm face with thumbs while
holding the edge of the diaphragm
with fingers.
3.7.1.5 Screw new diaphragm into compressor
by turning hand tight. DO NOT OVER-
TIGHTEN. Then back off until bolt
holes in diaphragm and bonnet flange
register.
3.7.1.6 Connect air line to lower air chamber
and load chamber with sufficient air
to move the diaphragm upward until
the backing cushion or elastomer
diaphragm rests against the
Advantage Act. lower cover. Do not
apply excessive air pressure that
results in inversion of the diaphragm.
3.7.1.7 Replace actuator assembly on body,
and tighten bonnet bolts hand tight.
3.7.1.8 Tighten bonnet bolts with a wrench,
crisscrossing from corner to corner.
See Table 1 for recommended
torques.
3.7.1.9 Apply sufficient air pressure to the
lower cover to fully open the valve. If
necessary, retighten bonnet bolts.
3.7.1.10 Travel stop (Closing Stop), if
equipped, must
be reset at this time
to assure proper closure. See Section
4.1.
3.7.2 Actuator Diaphragm or Spring Replacement:
(1/4” through 2”, DIN 8 - 50) If present, the switch pack-
age must be removed.
Spring-to-Close actuators contain powerful springs
and should not be disassembled unless properly fix-
tured.
One fixture exists for 1/2”, 3/4”, and 1” (DIN 15, 20, 25)
sizes, and another one for 1.5” and 2” (DIN 40 and 50)
sizes. No special fixtures are required for the 3” & 4” (DIN
80 & 100) sizes. Consult factory for details, see Figure 7.
3.7.2.1 Remove actuator from the valve body.
Apply air to lower cover to simplify dis-
assembly, then release air.
3.7.2.2 Remove valve diaphragm and plastic
indicator spindle plug (found on the
1/4” through 2” (DIN 8 - 50) spindles),
both unthread by turning counter-
clockwise.
3.7.2.3 Position actuator centrally in fixture,
locating the compressor over the cor-
rect spacer in the fixture lower plate.
3.7.2.4 Drop the stem guide through center of
fixture handwheel and position in actu-
ator indicator spindle #10-24 UNC
tapped hole (former plug location).
3.7.2.5 Turn handwheel clockwise until stop
rests on actuator top cover.
3.7.2.6 Remove all cover to cover
caps, bolts, and washers.
3.7.2.7 Turn handwheel counterclockwise until
spring load is relieved.
3.7.2.8 Remove top cover, lift out spring(s),
unthread indicator spindle, remove top
actuator plate and diaphragm.
3.7.2.9 Replace parts using the following pro-
cedure: Place the correct spacer,
dependent on valve size, over the pin
in the fixture lower plate. The 1 1/2”