Waters ACQUITY UPLC M-Class System Manual page 60

Table 4–2: Solvent manager maintenance procedures (continued)
Maintenance procedure
2
Replace the i Valve cartridge
Autozero the flow transducers
November 26, 2019, 715003588 Revision C
Page 60
Frequency
As part of the annual scheduled routine
maintenance and thereafter, as needed. The
typical failure modes are as follows:
• Retention times are later than expected
when a dynamic leak test is performed,
resulting in a leak rate above the
acceptable limit.
• The µBSM exhibits a low or erratic flow
rate or pressure pulsations.
• An intake valve error message occurs.
As needed. If you observe a measured flow
value exceeding +/- 10nL/min at a stop-flow
condition, autozero the flow transducers. In
the instrument console software, the
measured flow rates appear in the plot-data
channels Measured Flow Rate A and
Measured Flow Rate B of the µBSM. In
addition, autozero the flow controller modules
when these conditions exist:
• Laboratory temperature changes and
differs considerably from the laboratory
temperature during the last autozero
procedure.
• Seasonally, when the exterior
temperature changes significantly.
• When the mobile phase composition
changes significantly. For example, when
changing from a mobile phase containing
formic acid to one containing ammonium
formate, or from acetonitrile to methanol.
• After servicing the flow controller
modules.
Note:
The ASM has only one flow
transducer, on the B pump.
See also:
The online Help for instructions
explaining how to perform the autozero
procedure.