2
4-7. Bellows Unit Assembly (BUA) Replacement (Cont.) (See Figure 2-1)
COMPONENT REMOVAL NOTICE: See (separate) actuated instrument
Manual for particular components that must be removed to gain access to DPU
case mounting screws. Support DPU during disassembly. Do not loosen drive
arm hold plug (located in the top of the BUA center plate) when removing
mounting bracket. If plug is loosened, bellows ll uid will be lost
.
NOTE: The reference designations listed relate to Parts Drawing in Section 5.
1. Disconnect the DPU piping and remove the instrument from service.
2. Loosen the actuated instrument drive arm and slide off of the torque tube
shaft. Do not disconnect the instrument linkage
.
3. Remove the four case-retaining screws and remove the case assembly.
4. (Indicators only) Remove the three pipe mounting adapter bracket screws
(10, 11) and remove the adapter bracket (13)
.
5. Remove the three mounting bracket screws and remove the case mounting
bracket (18)
.
6. Remove the pressure housings bolts and pressure housings (26).
7. Place the pressure housings (26) on the replacement bellows unit assembly
(1) and insert and start (only) the pressure housing bolts.
8. Attach the case mounting bracket (18) to the replacement assembly, using
three mounting bracket screws
.
9. (Indicators only) Attach the pipe mounting adapter bracket (13) using three
screws
.
10. Support the DPU and tighten and torque the pressure housing bolts to the
specications listed in Tables 4-2 through 4-4. Refer to Housing Bolt
WARNING, para. 4-7, page 22
.
11. Attach the case assembly using four case retaining screws.
12. Attach drive arm and linkage.
13. Tighten drive arm to torque tube, per para. 4-8.
14. Replace any instrument components that were removed (refer to the
COMPONENT REMOVAL NOTICE above)
.
15. Calibrate the instrument before returning it to service.
23
To Next Page
Loading...
