The vacuum level will decrease slightly over a period of time. To bring it
back up, rotate the vacuum/vent valve to "EVACUATE" and start the
vacuum pump.
When the vacuum gauge again shows the desired level, rotate the
vacuum/vent valve to the setting marked "CLOSED" and shut off the
vacuum pump.
Caution
Do not pressurize the chamber above atmospheric pressure - the
oven will not withstand a positive internal pressure. When the vacuum
gauge reads zero, shut the gas off.
s
If the vacuum is to be replaced by ambient air, disconnect any tubing
attached to the hose connector marked "VENT" and rotate the
vacuum/vent valve to its "VENT” setting.
Use only a non-combustible, nonflammable, non-corrosive gas - such as
nitrogen or carbon dioxide - if application requires replacing the vacuum
with an inert gas.
Connect 1/4-inch ID tubing to the hose connector marked "VENT” and
connect the other end of the tubing to the regulator at the inert gas source.
Start the gas flowing at no more than 5 psi. Rotate the vacuum/vent valve
to the "VENT" position and shut off the regulator when the vacuum gauge
reads zero (normal atmospheric pressure).
The oven does not require very much gas to fill the chamber:
89508-426: Interior volume is 0.75 cubic feet.
89508-428: Interior volume is 2.30 cubic feet.
When the bake is completed and the vacuum has been released or replaced
as described earlier, turn the power switch to OFF. Open the oven door
and remove the dial thermometer. Take the contents from the chamber and
reinsert the thermometer with the sensing element in direct contact with
the center shelf.
6-2
Vacuum Oven
VWR Collection
Section 6
Operation
Maintaining Proper
Vacuum Level
Releasing the
Vacuum
Purging the Chamber
with Inert Gas
Unloading the Oven
