Flowserve XL90 Series - Manual (Page 7)

2. Remove the I/P module housing cover.
WARNING: Be certain power to the I/P module is discon-
nected before removing the housing cover in explosive
atmospheres; otherwise personal injury may occur.
3. Connect an adjustable current source to the terminal block
on the circuit board. Apply the desired input signal to the
positioner at which the output pressure is to fall to approx-
imately 1.7 psi. This signal can range from factory setting
of 3.7 to 8 mA.
4. Turn the minimum pressure cutoff pot clockwise until the
output pressure drops off.
5. Fine-tune the pressure drop-off point by increasing the
input signal and then decreasing it through the desired
shut-off signal. Observe the signal value at which the
pressure drops off. If the pressure drops off at a lower mA
signal than desired, turn the MPC pot counterclockwise. If
the pressure drops off at a higher signal than desired, turn
the MPC pot clockwise.
6. Repeat Step 5 until the pressure drops off at the desired
input signal.
7. To disable the MPC feature turn the minimum pressure cut-
off pot (marked “MPC”) 20 turns counterclockwise or until
it makes a clicking noise.
Positioner Maintenance
NOTE: Refer to NT 3000 IOM for I/P module maintenance
instructions.
For proper maintenance, proceed as follows:
1. Maintain a clean air supply, free of dust, oil and water. A
coalescing air filter for I/P is required to ensure a clean air
supply. Check and maintain filter regularly.
2. Make sure all arms and levers move freely.
3. Check for loose parts.
4. Be sure there are no leaks in the air supply tubing fittings or
connections.
5. Refer to the troubleshooting chart on page 9 in case of
problems.
Pilot Relay Disassembly and Reassembly
The pilot relay is available as a complete unit and can be easily
replaced (See Steps 2 and 18.) Before attempting to correct any
problem with the pilot relay assembly, obtain a positioner repair
kit that contains the soft goods most commonly required.
NOTE: Numbers in parentheses correspond to the numbers in
Figure 16.
1. Remove the feedback spring (47) and rotate the span and
zero arms (40, 46) out of the way.
2. Remove four screws (33) holding the pilot relay to posi-
tioner base (1). Remove relay from positioner.
3. Remove the nut (25) connecting the flapper assembly (21)
to the signal capsule.
4. Remove four screws (32) holding the two halves of the
pilot relay assembly together. Carefully pull the relay
assembly halves apart, making sure the flapper assembly
(21) slides off the flapper adjustment screw (19) without
damaging the signal diaphragm assembly (16). Pull the
relay diaphragm assembly (13) out of the other half of the
relay body (9).
5. With the relay assembly in two sections, remove two
screws (22) holding flapper assembly (21) to the relay
diaphragm assembly (13). Remove the flapper.
6. Remove diaphragm retaining plate (15) from relay
diaphragm assembly (13) and relay plate (14).
7. Replace relay diaphragm assembly (13) with one from the
positioner repair kit. Place the relay plate (14) between the
new diaphragms making sure the 1/16-inch diameter holes
between the relay plate (14) and the diaphragm line up.
Position diaphragm retaining plate (15) on relay diaphragm
assembly with rounded inner diameter edge against
diaphragm.
8. Attach flapper assembly (21) onto relay diaphragm assem-
bly (13) using two screws (22) with a locking adhesive on
the threads. The flapper assembly should extend away from
the 1/16-inch diameter hole through the relay plate. Make
sure lettering on flapper assembly is facing away from
diaphragm.
9. With relay halves still apart, remove relay tube O-rings (8)
from upper and lower bodies (9, 7) and replace them with
new O-rings (found in the positioner O-ring repair kit).
10. Remove rubber cap (35) and balance adjust screw cap
(36) from upper relay body (9). Remove O-ring (38)
from balance adjust screw and install new O-ring.
11. To remove and clean poppets (28), remove the retaining
rings (31), poppet covers (27), O-rings (30), and poppet
springs (29) found at the end of each housing. After remov-
ing poppets, inspect them for dirt buildup or damage to
seating surfaces.
12. The upper relay body (9) has a movable seat ring (34)
which is adjusted with the balance adjust screw (36). This
seat is removed by pushing it out with a soft instrument
such as a wooden dowel. Be careful not to damage seating
surface. Remove O-ring (37) from the seat ring (34).
13. Lubricate and replace the O-ring (37) on movable seat ring
(34). Carefully reinstall the seat ring (34) into upper relay
body (9), being careful not to damage seating surface or
O-rings.
14. Reinstall poppets (28), poppet springs (29), Seat Spring
(39), O-rings (30), and poppet covers (27) before installing
retaining rings (31).
15. If signal diaphragm assembly (16) is damaged, proceed as
follows: With relay halves still apart, remove four screws
(32) holding signal diaphragm assembly (16) to the pilot
relay assembly. Remove locking screw (23), washer (24),
Flowserve Corporation, Valtek Control Products, Tel. USA 801 489 8611 48-7