Emerson Rosemount 2151N Reference Manual page 68

Rosemount 2151N
Process Flange Reassembly
Figure 5-12 – Process O-rings
59
1. Replace the process O-rings (C-ring for AP
transmitters) (9) with new O-rings (C-ring) if the flange
(10) was removed. Carefully place one O-ring (C-ring)
in each of the two weld rings located on the isolating
diaphragms of the sensor module (8) as shown in
Figure 5-12.
2. Carefully place the process flange on the sensor
module. Take care not to disturb the O-rings (C-ring)
or damage the isolating diaphragms.
3. With the process flange sitting securely on the sensor
module, install two flange cap screws (13) into the
flange location shown in Figure 5-13. Install the cap
screws finger tight.
4. Place the four bolts (11) through the process flange
and screw them on finger-tight.
5. Using a hand torque wrench, evenly seat the flange
onto the sensor module by following steps 6 through 9
(see Figure 5-13 to identify the bolts).
6. Alternately tighten the four bolts in the sequence
shown in Figure 5-13 to 150 in-lb ±15 in-lb (16.9 N-m
± 1.7 N-m)
7. Repeat step 6.
8. Repeat step 6 at 300 in-lb ± 25 in-lb (33.9 N-m ± 2.8
N-m)
9. Repeat step 8.
10. Torque the two cap screws in the flange to 33 in-lb ±
1.7 in-lb (3.7 N-m ± 0.2 N-m). NOTE: Cap screws
must be torqued after bolts, or they will loosen.
Reference Manual
00809-0000-4851 Rev AD
December 2023
Maintenance & Troubleshooting