Thermo Scientific 3166547, Operator'S Manual

Page: 9 / 21

4
TEMPERATURE ADJUSTMENT
Turn the power switch "On". Turn the regulating
control knob and the safety control knob fully
clockwise. The regulating pilot light should glow,
indicating the oven is being heated.
When the desired safety temperature is reached
(usually 2-3°C above the regulating temperature)
as indicated on the pyrometer, turn the safety
control knob counterclockwise until the safety pilot
light glows. At this time the regulating pilot light
will turn off. Allow the oven to cycle several times
(3 to 4 hours) to establish the desired safety
temperature. Adjust the safety control knob up or
down as necessary.
Turn the regulating control knob counterclockwise
until the regulating or safety pilot light turns off.
Adjust the regulating control knob down until the
desired operating temperature is obtained. Allow
the oven to cycle several times (3 to 4 hours) to
establish the desired operating temperature. The
regulating pilot light will cycle on and off, indicating
normal operation. The safety pilot light should stay
off.
If at any time the safety pilot light glows, check the
controls to be sure the safety control is not set
below the regulating control.
Oven thermostats are set for operation at
temperatures over 100°C.
For control at lower temperatures, readjustment
of the thermostat may be necessary.
Two allen wrenches are required:
•
1/16" for the thermostat shaft
• 5/64" for the thermostat knob
1. Bring oven to room ambient.
2. Energize oven.
3. Set thermostat fully counter-clockwise (heat
lamp is on).
4. Remove thermostat knob. Note small allen
screw within shaft .
5. Turn shaft allen screw clockwise until lamp
goes out.
6. Attempt to control at the desired temperature.
7. It may be necessary to repeat this procedure.
NOTE
WHEN THE OVEN IS NEW AND IS FIRST HEATED,
THE INSULATION WILL BECOME SCORCHED AND
SOME SMOKE AND BURNING ODOR WILL OCCUR.
IT IS NORMAL FOR THIS CONDITION TO LAST 2
TO 3 HOURS AT HIGH HEAT.
VACUUM OPERATION
The following information serves as a guide to
operation of the vacuum system.
The total variable leak rate of the oven is 3 inches
of mercury per cubic foot per 24 hours at 29 to 26
inches of mercury.
Vacuum Sealing Agents
High vacuum silicone grease is often necessary
to provide a proper seal at tubing connections,
valve connections, door seals, etc. This is
especially important at high vacuums. However,
there are restrictions to using silicone grease,
depending upon the type of materials placed in
the oven. Refer to the maintenance section of this
manual for restrictions.
Out Gassing
The operation of the oven at high temperature while
evacuating the chamber will help drive off absorbed
gasses on the walls and other surfaces and
facilitate attainment of high vacuums.
Evacuating Chamber
Connect vacuum tubing to either hose connection
on side of vacuum oven. Turn on the vacuum
pump, then open the valve on the oven. The
vacuum gauge will indicate when the desired
pressure level is obtained. Once obtained, close
the valve, and turn off the vacuum pump. Air may
be bled into the chamber through the unused valve
to raise the pressure level.
NOTE
TO MAINTAIN AS LEAK PROOF A SYSTEM AS
POSSIBLE USE ONLY VACUUM PUMP TUBING.
MAKE SURE ALL CONNECTIONS ARE TIGHT. USE
A VACUUM PUMP SIZED TO ADEQUATELY
EVACUATE THE OVEN VOLUME.