ABB SensyMaster FMT430 Operating Instructions Manual page 33

SensyMaster FMT430, FMT450 THERMAL MASS FLOWMETER | OI/FMT430/450-EN REV. B
3. Use the appropriate screws for the holes.
4. Slightly grease the threaded nuts.
5. Tighten the nuts in a crosswise manner in accordance with
the figure. First tighten the nuts to approx. 50 % of the
maximum torque, then to 80 %, and finally a third time to the
maximum torque.
Note
Torques for screws depend on temperature, pressure, screw and
gasket materials. The relevant applicable regulations must be
taken into consideration.
Figure 19: Tightening sequence for the flange screws
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