ThermoWorks 271-3XX 3001 DRY-WELL PORTABLE MINI HEAT SOURCE - Manual (Page 4)

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To show the set point temperature in the display press and
release either the up or down arrow button [up/down ill]. Press
and hold either the up or down arrow button [up/dn ill] to
change the set-point value.
A shift can be entered into the controller by pressing the
scroll (left-hand) button. Press and hold either the up or down
arrow button [up/dn ill] to change the shift value. A factory set
value will be entered at the time of certification. The shift value
should only be adjusted if the unit is being monitored by a
precision reference thermometer.
All other functions of the controller have been factory set and
locked to maintain accuracy and repeatability.
3.2 Operation
3.2.1 Dry-Block Set-Up
Place the dry-block unit on a flat level surface with at least 6
inches (150mm) of space in front and behind. The stand may
be swung out to lift the front of the unit. Plug the power cord
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 cord. The fan will start immediately and the
controller display will illuminate after approximately three
seconds.
3.2.2 Temperature Setting
The dry block may be set to any temperature between +91°F
and 572°F (+33 and +300°C) in 0.1° increments (see 3.1.6
Temperature Controller for details). The control will cause the
unit to heat or cool to the set point temperature. A control
indicator light will show in the top left corner of the display
when the heater is active. The dry-Block temperature is
displayed in operation. A small overshoot and undershoot
will occur when the block reaches the set point temperature.
Ten 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 block
temperature should stay within ±0.9°F (±0.5°C) of the set point
temperature.
3.2.3 Probe Testing
Insert the probe to be tested into one of the holes in the Dry-
Block. 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-Block hole of closest size to the
probe diameter. Allow the reading from the probe to stabilize
and then compare the reading with either the temperature
controller display or an external reference thermometer. For
optimum accuracy use a high precision reference thermometer
and probe. If probes with a large mass are inserted into the
Dry-Block holes the unit will require up to 10 to 15 minutes to
re-stabilize.
3.2.4 Display Units
The dry-block is shipped from the factory with display units
set to °F or °C. This can be reset at the factory. Call for
details.