Labconco FreeZone 2.5 Liter Freeze Dry Systems 76705 Series - Manual (Page 41)

Chapter 7: Troubleshooting
Product Service 816-333-8811 or 1-800-522-7658 37
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 operating, depending on ambient temperature and humidity.
FreeZone Cascade Freeze Dry Systems should achieve a collector temperature of
-84°C or lower when the vacuum pump is operating. If the collector temperature
does not reach the design temperature within 30 minutes, then the refrigeration
module is not functioning properly.
Cascade Systems (those that operate @ -84°C) consist of two vapor-compression
refrigeration systems in series connected together via a heat exchanger. Each
system has a compressor, condenser, capillary tube metering device and an
evaporator. During the operation the evaporator of the “high stage” system
refrigerates the condenser of the “low stage” system. This takes place in the heat
exchanger. The low stage and high stage systems are balanced by design,
however, sometimes that balance can be disrupted during operation and the unit
will not function properly. If the unit is overloaded, or if the unit is defrosted and
restarted in a short time interval, system unbalance is possible. If system
unbalance occurs, turn the Freeze Dryer off and allow the unit to soak at ambient
temperature for 2 to 4 hours.
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.