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OPERATOR MAINTENANCE
Note: Does the car actually have gas in the tank? Have you physically verified the computer is
plugged in? Yes, we are going ask some very basic questions. Please bear with us.
Methodical verifications and the elimination of potential causes of failure are often the
quickest means of getting a unit back into operation.
Unit Performance Specifications
Verify the following items to ensure a fault in the unit is preventing it from achieving its specified
performance levels.
• Is the chamber being evacuated for the full duration of your baking application?
o Any outgassing from samples or products will raise the chamber pressure if the vacuum
valve is closed or the vacuum pump is turned off.
• The chamber must be evacuated to a minimum of -3 inHg (684 torr) to maintain a seal.
o The door will not seal completely at pressures higher than this.
o The vacuum pump must be rated to a minimum flow capacity of 1 cubic foot per minute (cfm)
per cubic foot of the chamber volume. Example: a 2 cubic-foot chamber should be
connected to a pump that can evacuate at least 2 cubic-feet per minute.
• Is the vacuum pump type suitable for your application or process?
o The vacuum pump must be resistant to byproducts outgassed during the baking process
with a sufficient evacuation rate to achieve your vacuum target.
• Is the gasket type suitable for the application?
o Each gasket type is resistant and vulnerable to different outgassed byproducts. A gasket
that is vulnerable to byproducts from your applications may fail after only a short period of
use.
o See page 60 of the operation manual to verify that the installed gasket is suitable for your
application.
Vacuum Specifications
Vacuum ovens cannot obtain perfect seals. The following specifications are the best performance
that can be expected of the oven in maintaining a vacuum environment.
• The baseline leak rate of the oven is less than 1 mTorr per 30 minutes at ambient temperature
when the oven chamber is empty.
• The lowest rated chamber pressure is less than 20 mTorr at 150°C.
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