Labconco FreeZone 6 Liter Benchtop Freeze Dry Systems 77520 Series - Manual (Page 40)

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Chapter 7: Troubleshooting
Product Service: Domestic 1-800-522-7658, International 816-333-8811
If vacuum problems continue, consider obtaining a second vacuum
gauge capable of reading a vacuum of 0.010 mBar. It is often
useful in determining if the vacuum pump is operating properly
and the vacuum sensor reading is accurate.
4. Isolate the pump by disconnecting the vacuum hose from
the Freeze Dryer. Deadhead the pump by inserting the
vacuum sensor from a secondary vacuum gauge into the
end of the vacuum hose and observe the vacuum reading
obtained. Confirm that the pump is capable of achieving an
ultimate vacuum less than 0.010 mBar or approximately 10
microns. If an inadequate vacuum reading is obtained, the
pump has most likely failed and may need to be replaced or
rebuilt.
II. Gaskets, Tubing, Connections, Sample
Valves
1. Check all sample valves on the drying chamber/manifold
and ensure all valves are closed or in the vent position.
Check to ensure all fittings are tight and sealed properly
against the chamber. Inspect valves for cracks or cuts.
2. Inspect gasket(s) for cracks or defects. Ensure the gasket is
clean. Apply a thin coat of vacuum grease to the gasket.
Keep in mind too much vacuum grease can actually cause
leaks.
3. Check the drain line and ensure the drain plug is installed
and the tube appears to be in good condition.
4. Check all rubber vacuum tubing for signs of deterioration
or cracking.
5. Check all connections and make sure they are secure and
leak tight.
6. When checking the sample valves, pull as much vacuum as
possible. If a vacuum indication is displayed, wiggle or
rotate the valves and watch the gauge for any fluctuations.
Fluctuations can indicate a potential vacuum leak. If the
valve seems to be in good condition, remove the valve and
apply a thin coat of vacuum grease to the stem and the
outside sealing surface of the valve body, and reinstall the
valve. DO NOT APPLY VACUUM GREASE TO THE
SAMPLE VALVE GASKETS, WHICH SEAL TO THE
WALL OF THE DRYING CHAMBER. If the valve still
seems to be the source of the problem, remove the valve
and stopper the hole with a rubber stopper. Continue
checking the other valves.