1) Removing the flask needs to be done periodically if you want the
instrument well maintained, but replacing it can lead to flask assembly
damage if tightened too tight. We found that overtightening leads to
stripping of the inside threads on the white cap assembly part (thus your
turning observation). When replacing the flask we gently hold the flask
with only th index finger and thumb and VERY gently turn until resistance
is met. To leak test we deliver L2 then bubble the flask while turning off
the vent. You should notice that the bubbling rate almost stops after a
little while.
2) We replace the flask every month if no problems are onserved and replace
with either a new one or clean it out with KOH. If we start seeing air
injections (large peak coeluting with GLU) or see a high background of
aniline we replace the flask ealier than 1 month. We will reuse a flask
only once and simply buy a new pack from HP (they come in packs of three
and are cheap relative to down time of the instrument).
3) We replace the flask assembly every year regardless of whether it is
working or not. The small black gasket used the form the seal has never
been a source of problems in our lab.
4) We always have a spare flask assembly that we have checked when it comes
in. YES, we have also had our problems with incorrectly configures flask
assemblies and assemblies that simply do not work. HP has always replaced
a bad flask.
We have not really had problems with the assembly any more after
following the above guidelines. Best of luck with your instrument.
Joe
Joseph Fernandez
Associate Director
The Rockefeller university
Protein/DNA Technology Center
1230 York Ave. New York, NY 10021
Phone: (212)-327-8869
FAX : (212)-327-8620
email: fernaj@rockvax.rockefeller.edu
Lab Web Page: http:\\pdtc.rockefeller.edu