Labconco FreeZone Plus 4.5 Liter and FreeZone -105 C Cascade Freeze Dry Systems 73870 Series - Manual (Page 39)

Chapter 7: Troubleshooting
Product Service 816-333-8811 or 1-800-522-7658 35
The following test determines if a vacuum leak is in the collection chamber.
1.
Insert a rubber stopper in the small hole in the rear of the collector
chamber and another in the drain port in the bottom.
2.
Start the freeze dryer and observe the vacuum indication. If the
vacuum is good, the problem is in the collection chamber. If it is bad,
the problem is in the plumbing connections from the collection
chamber to the vacuum pump.
3.
If the leak is in the chamber, check the bulkhead fittings where the
collection coil passes through the button of the chamber.
4.
If the leak is in the plumbing connections, check all rubber parts, the
drain hose, the drain plug, fittings and clamps.
Checking the connections to the pump and the vacuum tube