Metrohm 873 Biodiesel Rancimat Manual User Manual
Page 170
6.1 Problems
￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
162
￭￭￭￭￭￭￭￭
873 Biodiesel Rancimat
Problem
Cause
Remedy
The conductivity measuring
cell is contaminated.
Check measuring cell (see Chapter
4.8.4.2, page 146) and, if necessary,
clean.
See also: The induction times
are not reproducible for multi-
ple determinations.
The induction time is
longer/shorter than
expected.
The temperature is not selec-
ted correctly.
￭
Ensure that the correct method for the
determination has been selected.
￭
Check that Temperature and
Delta T have been specified correctly
in the method (see Chapter 4.5.2.1,
page 60).
See also: The induction times
are not reproducible for multi-
ple determinations.
The stability time is lon-
ger/shorter than expec-
ted.
Delta Kappa is not defined cor-
rectly.
Ensure that the value of Delta Kappa
defined in the method is correct (see
Chapter 4.5.2.2, page 64).
See also: The stability times are
not reproducible for multiple
determinations.
See also: The induction time is
longer/shorter than expected.
The measurement
curves are extremely
noisy.
The air supply for the measur-
ing solution is directed to the
conductivity measuring cell.
measuring vessel cover, turn the PTFE
tube (5-
) in such a way that the air is
no longer directed to the measuring cell
and fix in this position.
Gas bubbles adhere to the
conductivity measuring cell
during measurement.
￭
Ensure that the measuring cell is clean
and free of fat. If necessary, clean
thoroughly (see Chapter 4.6.4, page
80).
￭
In some cases ultra pure water con-
tains a large proportion of dissolved
air which escapes during measure-
ment. In this case, degas the ultra pure
water before the measurement for 5
to 10 min in a vacuum.