Brooks Instrument 5851i - Manual (Page 37)

4-9
Installation and Operation Manual
X-TMF-5851i-MFC-eng
Part Number: 541B109AAG
September, 2009
Brooks ® Model 5851 i
Section 4 Maintenance
& Troubleshooting
12. Remove the adapter fittings and O-rings (27) from the flow controller
body (14).
13. Remove the four screws (29) from the end block (28) and carefully
remove the end block.
14. Remove the restrictor assembly (21) from the inlet side of the flow
controller body (14) using the header removal tool (Section 5, Table 5-
2). Note the rotational position of the restrictor assembly. (Refer to
Section 4-7)
B. ASSEMBLY
NOTE: It is recommended that all O-rings be replaced during controller
assembly. All O-rings should be lightly lubricated with Fomblin lubricant
(part of O-ring kit, Section 5) prior to their installation.
1. Examine all parts for signs of wear or damage, replace as necessary.
2. See Section 4-7 Restrictor Sizing, Assembly Procedures, Steps 1
through 3 on Page 22.
3. Place the end block O-ring in position and install the end block with
the four hex socket screws. Tighten these screws to 49 inch-lbs. Do not
overtighten.
4. Press the lubricated sensor O-rings (17) into the flow controller body
(14). Install the sensor assembly and secure with two screws (18) and
washers (19) and tighten to 15 in./lbs.
5. Install the orifice (12) and its O-ring (13) using a 3/8 nut driver. Insure
that the orifice is fully seated but do not overtighten.
6. Insert the valve preload spacers (10), if used, into the valve cavity in the
flow controller body (14). Use care to preserve the correct order.
7. Install the valve plunger assembly (7, 8, 9 and 11) on the preload
spacers (10). Install air gap spacers (10), if used, on top of the valve springs.
8. Install the valve stem assembly (6), secure with the valve retaining plate
(4) and four hex socket screws (3). When installing the screws, they
should first make light contact with the plate which should be checked
to insure that it makes full contact around the stem assembly. Torque
the screws securing the valve retaining plate in a diagonal pattern
(Refer to Figure 4-1) to 15 in./lbs.