Labconco FreeZone 4.5 Liter Freeze Dry Systems 77510 Series - Manual (Page 37)

Chapter 7: Troubleshooting
Product Service 1-800-522-7658 33
III. System Components and Collection Chamber
Isolation
The following test is used to check the collection chamber integrity and
connections. The figure below points out potential areas to locate a leak.
 Fill the collection chamber with approximately 2 inches of water, enough to
cover all fittings. Remove one wire from the moisture sensor. Replace the
collection chamber lid and turn on the vacuum pump. Allow the vacuum
pump to run for approximately 5 to 10 seconds. (If the vacuum pump is left
on, the water will begin to boil and the test will not be effective). Look inside
the chamber for any bubbling while the pump is running and after you shut the
pump off.
 If bubbling is observed around the bulkhead fittings, access the bottom of the
chamber and remove the insulation. Tighten the appropriate fitting by placing a
wrench on the fitting inside the chamber and use a second wrench to turn the nut
on the bottom of the chamber. Be careful not to damage the evaporator coils or
the brazed joints to the refrigerant system. Once the fitting is tightened, perform
the test again. Should the bubbling still be present, loosen the bulkhead fittings
and apply vacuum grease to the O-rings, then reassemble and test.
 If bubbling was observed on the chamber surface, the chamber must be
replaced. This type of leak cannot be successfully repaired. The leading cause
of a chamber surface leak is corrosive residue left in the chamber after use.
Refrigeration Module Operation
Under a no-load condition, the FreeZone Single Stage Freeze Dry System can
achieve a collector temperature of –50°C or lower within 30 minutes when the
vacuum pump is running, depending on ambient temperature and humidity.
If any repairs are required on the refrigeration module, contact your local
laboratory supply dealer. If your laboratory supply dealer is unable to provide
assistance, please call Labconco. Repairs should only be undertaken by a
competent refrigeration technician or through an authorized Labconco service
agency.