7
OPERATION
DRY-WELL SET-UP
Place the dry-well unit on a flat level surface with at least 150 mm of
space all round. The stand may be swung out to lift the front of the unit.
Plug the power supply lead into a suitable grounded AC power outlet
socket. Check for and remove any foreign objects prior to switching
on. Turn the instrument on using the switch located on the rear panel,
below the power lead. The fan will start immediately and the controller
display will illuminate after approximately three seconds.
TEMPERATURE SETTING
The dry-well may be set to any temperature between -10 to 110 °C in
0.1 °C increments (see 'Temperature Controller' section for details). The
control will cause the unit to heat or cool to the set point temperature.
The dry-well temperature is displayed in operation. A small overshoot and
undershoot will occur when the well reaches the set point temperature.
10 minutes is normally required to reach a higher set point temperature.
It will take longer to reach a lower set point temperature. Once the set
point temperature is reached, a further 10 minutes should be allowed
for stability to be achieved. For optimum accuracy and stability allow
the unit to warm up for 30 minutes after power up. The displayed well
temperature should stay within ±0.5 °C of the set point temperature.
PROBE TESTING
Insert the probe to be tested into one of the holes in the dry-well. The
probe should be a snug fit for good heat transfer but should not be so
tight that it cannot be removed easily. Best results will be obtained when
the probe is inserted to the full depth of the dry-well hole of closest size
to the probe diameter. Allow the reading from the probe to stabilise
and then compare the reading with either the temperature controller
display or an external reference thermometer. For optimum comparison
accuracy use a high precision ETI Reference Thermometer or similar.
If probes with a large mass are inserted into the dry-well holes the unit
will require up to 10 to 15 minutes to re-stabilise.
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