Buchi DuMaster D-480, Operation Manual

Page: 216 / 354

Operating instructions DuMaster D-480 ©BÜCHI Labortechnik AG
8 - Maintaining the instrument 216
Note:
When you close a ground-in ball-and-socket joint, you must be able to feel an elastic
resistance when you press-in the o-ring, otherwise you must replace the o-ring.

Close the front door.
Phase 3: Follow-up work, gas pressure/ tightness

After completing all maintenance work, put the instrument back into a state ready for
measurement. See Start-up.
Phase 4: Performing the necessary follow-up work
Proceed as follows:

Perform blank value determinations to test complete combustion. See
Determining blank
values
(on page 141). Allocate an oxygen dosing time of 90 s to the sample.

Only stop the measurements once you have reached low, stable blank values. See "Measure of
gas-tightness (N blan value)" in Types of blank value determination and their settings.
To be observed after maintenance
If you have performed maintenance work that has a defined maintenance interval, you must manually
reset the "Status" field to zero on the "Maintenance intervals" dialog (accessible via
Options >
Maintenance > Intervals
. See Defining maintenance intervals in the software.