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Appendix

Revision 004, 12/09 39

Appendix A: Troubleshooting

Vacuum Problems

Remember that maximum vacuum is only achievable with a clean, dry system. Initial

vacuum will be affected by the amount of product loaded on the unit. For efficient

freeze-drying, vacuum should be below 200 mT. When using Quickseal valves,

product may need to be introduced in stages to keep the vacuum below acceptable

levels.

Consider the following when attempting to pinpoint vacuum-related problems:

• Was the condenser defrosted and drained after the last run?

• Is the chamber clean and dry?

• Is the drain fitting inserted into the drain receptacle? If so, it must be

removed.

• Are all accessory ports, valves and filters closed tightly? Check all

connections for integrity.

• Is the door gasket clean and properly greased?

• Are all Quickseal valves in the closed position?

• Are the Quickseal valves in good condition? Is a light coating of vacuum

grease visible on the valve plug and on the stainless steel valve port?

• Is the vacuum pump oil clean and at the proper level? Check sight glass.

• Is the condenser maintaining the proper temperature? If the temperature

rises due to refrigeration problems, moisture may be leaving the

condenser walls and migrating to the vacuum pump, causing poor

vacuum.

If none of the above applies, try to isolate the problem by removing the manifold or the

vacuum cover plate and placing a stopper in the vacuum intake tube at the bottom of

the condenser. This will seal the vacuum tube. When the vacuum pump is operated,

check the components between the pump and the end of the tube.

If you get a vacuum reading below 500 millitorr within one (1) minute, you can rule out

any problem with the pump, vacuum probe and vacuum tubing connections. Recheck

the manifold and gasket for joint separations and dirty or rough surfaces.

If you do not get a normal vacuum reading on the front panel display or vacuum

gauge within one (1) minute, start checking components individually.

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Sentry Sentry 2.0 Betreibershandbuch Seite 49