User guide

Columns and Oven 9
Advanced User Guide 281
Final temperature Temperature of the oven at the end of a
heating or cooling rate.
Final time Time in minutes that the oven will be held at the
final temperature of a temperature- programmed rate.
Total length of a run is determined by its oven temperature
program. The maximum allowable time for a run is
999.99 minutes. If the program is still running at that time, the
run terminates.
Post run
This function can be used with both isothermal and
programmed methods. Post run is a period that begins at the
end of the normal run. The parameters are:
• Time—How long is the post run period?
• Temperature—What is the oven temperature during the post
run period?
• Column pressures—What are the pressures at the column ends?
Post run may be used to clean out a column in preparation for
the next run, backflush a column to eliminate high- boilers, and
other functions.
When the Post run Time elapses, the GC returns to the initial
state defined in the current method. If it uses cryogenic cooling
and you do not start another run quickly, you could waste
considerable coolant while waiting for the next run. A solution
is to use a sequence that loads a less wasteful method.
Oven ramp rates
To use the fast oven ramp rates (a 240 V power option is
required), your electric service must be able to supply ≥ 200 V at
≥ 15 Amp.
The highest rate that you can achieve depends on many factors,
including the room temperature, temperatures of the inlets and
detectors, the amount of material inside the oven (columns,
valves, etc.), and whether or not this is the first run of the day.
The optional oven insert for fast chromatography (see “About
the Oven Insert” on page 284), increases oven ramp rates for the
back column. Table 61 lists typical oven ramp rates.