2700A — ©2015, February, 2015
P.O. Box 40525, Houston, Texas USA 77240-0525
Tel: 713·466·3552 · Fax: 713·896·7386
www.norriseal.com
O
PERATING AND
M
AINTENANCE
M
ANUAL
Series 2700A Control Valve
Reverse Steps 1 through 8 of the
Actuator Disassembly Instructions.
B. For direct actuators:
Reverse Steps 1 through 9 of the
Actuator Disassembly Instructions.
2.3 Valve Disassembly
A. Balanced Plug Control Trim
Use care to avoid damaging gasket
sealing surfaces. The surface finish of
the valve stem is critical for making a
good packing seal. The inside surface
of the cage assembly or cage retainer
is critical for smooth operation of the
valve plug and for making a seal with
the plug seal ring. The seating surfaces
of the valve plug and seat ring are
critical for tight shutoff. Assume all of
these parts are in good condition when
disassembling the valve and protect
them accordingly.
Loosen the lock nut on the
actuator stem and turn the
nut above it counterclockwise
to completely remove the
spring’s preload. This will leave
the diaphragm attached to
the valve bonnet. (Alternately,
completely remove the actuator
by following steps 1-4 in Section
2.1 above.)
Remove the nuts from the bonnet
flange studs.
Lift the bonnet off the body along
with guide, cage, plug and stem,
being careful to lift straight up to
avoid scoring or damaging the
valve internals.
Separate the plug from the stem
by driving out the plug pin with a
punch and turning the plug, cage
and guide counterclockwise. The
plug pin is exposed and visible
Page 3 of 12
T A B L E 2 MA I N T E N A N C E S C H E D U L E *
ITEM INSPECTION SCHEDULE
Valve Trim
(Seat, Plug,
Cage &
Guide)
Bonnet
Body
Stem Packing
Actuator
Seals
Inspect every 6 months, under normal service conditions
(low pressure drop and no sand or abrasives in fluid).
Or inspect every 2 months, under service conditions, such
as high pressure drop, corrosion, or fluid with sand.
Inspect bonnet once a year or whenever trim inspection is done.
The body should last many years under normal conditions.
However, under severe conditions of corrosion or erosion from
sand in the flowing fluid, high pressure drops, or high fluid
velocity, body life may be greatly reduced. Inspect the body
each time the bonnet is removed.
Inspect packing at least once a year.
Inspect diaphragm, spring and stem once a year.
Replace gaskets and inspect O-rings each time valve is
disassembled.
* Under certain operating conditions, this suggested maintenance schedule will not be adequate and a shorter time
schedule may be required.
A parts list drawing showing the valve configuration is available. Please contact your Norriseal
sales representative for this information.
2.1 Actuator Disassembly
For all spring-diaphragm
actuators
Remove instrument air from the
actuator.
Loosen the lock nut on the
stem and turn the adjusting
nut counterclockwise until the
spring’s preload is completely
removed and is de-energized.
Unscrew the two cap screws on
the stem connector and remove
the stem connector.
Unscrew the yoke lock nut using
a metal punch or narrow flat
metal bar and hammer. Remove
the actuator yoke from the valve
bonnet.
Unscrew the cap screws around
the diaphragm housing and
remove the upper housing.
Remove the lock nut and
adjusting nut from the actuator
stem (reverse actuators) or the
actuator body (direct actuators).
On reverse actuators, the spring
retainer and actuator spring will
be held to the adjusting nut by
gravity and will be removed
when the adjusting nut is
removed. The actuator may be
inverted or laid on its side for
this step.
Remove the diaphragm plate/
diaphragm/stem assembly from
the yoke.
Unscrew the jam nut on top of the
diaphragm stem and disassemble
the lock washer, diaphragm plate,
diaphragm and stem.
On direct actuators, remove the
spring and lower retainer from
the yoke.
2.2 Actuator Reassembly
A. For reverse actuators:
1.
1.
3.
3.
2.
2.
4.
4.
5.
6.
7.
8.
9.
CAUTION!