TANNER Scientific TN50 Operating Instructions Manual page 31

9.4 AUTOMATIC/MANUAL DEFROST
For an optimal effect of the cooling machine, a low thermal resistance at the cooling
ribs is necessary. Frequent use of the cooling machine condenses moisture on these
cooling ribs and increases the thermal resistance. Therefore, the device, in particular the
cooling ribs, is automatically defrosted.
During an automatic defrost (programmed for every midnight) or an manual activated
defrost (possible at every time) hot gas from the cooling system is pressed through the
evaporator. All ice which has been built up is melted, the water drops into the
condensate bottle.
The defrosting process ends at a temperature of 20 °C on the evaporator. The chamber
temperature remains in the minus range, so that samples which are stored there do not
thaw.
i
The defrost process starts automatically at midnight every day. To
change this time, please refer to section 7.3.
Before starting a complete defrost of the instrument, assure that all
samples have been removed from the cryochamber.
i
Before switching on the instrument ensure that the instrument is
completely dry, otherwise ice built up can damage mechanical parts
Operating Instructions – TN50
During defrosting (automatic or manual) always leave front
window open.
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