Temperature Control
Oven safety
51
In complex two•or three•rampoven temperature programs, information
as to the part of the program in progress is monitored by pressing
OVEN TEMP
.
Note that, during a ramp, the SETPOINT value displayed is that
calculated to be the correct temperature, based upon specified
heating/cooling rate, and initial and final oven temperatures.
Also, note that if the RATE LED is observed to blink during oven heating,
this indicates the particular
RATE
value entered is too aggressive for the
given operating conditions: the oven heater is operating at full power and
may not be able to deliver the desired temperature program rate. Such a
situation compromises accuracy in repeating the heating ramp from run
to run.
Oven safety
Normally, the oven should be switched off (
OVEN TEMP
OFF
) prior to
accessing the oven interior (e.g., to change columns, check for leaks, etc.).
For safety, this turns off power to the oven heater, fan, and cryogenic
valve (if installed), but maintains the setpoint value in memory.
The oven is equipped with a shut•offfeature to protect against
unintentional opening of the oven door, and/or the possibility of
mechanical and/or electronic failure affecting oven operation.
At any time during normal above•ambientoperation, if the oven cannot
attain and/or maintain an entered setpoint temperature, a problem is
assumed and the oven is automatically switched off. Examples of possible
problems include the oven door open (or closed but not properly latched),
inoperative oven vent flaps, failure of the oven fan, heater, or
temperature sensor, or electronic problem.
If the oven door is opened, a time delay may be observed before the
oven shuts itself off. The closer the oven is to ambient temperature,
the longer the delay will be.
WARNING
