If an O-Ring seal is used, it is installed in the groove
between where the Guide Ring is installed and
where a Spring Energized Seal would be installed
(Figure 16).
11. Install the Guide Ring(s) onto the Main Valve Piston.
If there is more than one Guide Ring, stagger the cut
locations 180° apart.
12. To prevent seal damage during assembly, check the
chamfer on the bottom of the Cover Plate for burrs.
If any sharp edges exist, polish the chamfer.
13. Insert Main Valve Piston (energize seal/o-ring side
first) into bottom of Cover Plate. Continue pushing
Main Valve Piston into Cover Plate, being careful not
to pinch the guide rings. Push Main Valve Piston in
until bottom of Main Valve Piston is even with the
bottom of the Cover Plate.
14. Install 1/4” MNPT pipe plug into Cover Plate where
dome line connects.
15. Install Cover Plate Gasket. Install Cover Plate on top
of Base such that the pilot will be aligned for proper
tubing connections. Make note of the length of the
studs. The two longer ones will straddle the vertical
line of the inlet sensing port on the Main Base of
the pilot valve. Install the bracket between the
Cover Plate and the Nut or Cap Screw. Be sure that
the bracket is aligned so that the two smaller pilot
attachment holes are above the horizontal plane of
the Cover Plate.
16. Remove pipe plug from Cover Plate.
17. Torque to the values found in Table 11 using the
torque patterns in Figure 40 and Table 12.
18. Once the Main Valve is assembled before any tubing
is connected reach through the hole in the center
of the Cover Plate and force the Main Valve Piston
down until it contacts the Disc Holder. Failure to
complete this procedure will prevent the Main Valve
from loading and closing, when pressure is applied to
the valve.
19. The Main Valve is ready to receive the pilot and
finished assembly.
Table 12: Torque Required
for Each Round of Pattern
Round
Percentage of Required Torque
1
Wrench Tight
2
25
3
60
4
100
5
100
4
Holes
1
3
2
4
6
Holes
1
3
2
5
6
4
12
Holes
1
7
9
3
2
8
12
5
6
10
11
4
20
Holes
1 7
9
3
2
8
12
13
17
15
20
14
5
6
10
18
11
19
16
4
8
Holes
1
7
3
2
8
5
6
4
Figure 40: Bolt Tightening Patterns
XVI. Reassembly of the 2900 Main Valve (Contd.)
48 | BHGE
© 2018 Baker Hughes, a GE company. All Rights Reserved.
