Lauda RA 12, Руководство по эксплуатации, Страница: 16 / 52

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4.5 Materials
All parts being exposed to the heat transfer liquid are made of high quality material appropriate to the operating tem-
perature. Non-rusting stainless steel and high quality temperature-resistant materials are being used.
4.6 Temperature indication, control and safety circuit
The units are equipped with a 4-character LED display, which is used for the display of the measurements and settings,
as well as the operating status. The entry of setpoints and other settings occurs under menu guidance via three keys.
With low level, overtemperature or other alarms the unit switches off the heater on all poles. The pump and the refriger-
ating machine are also switched off. Unlocking the protection system (

7.11.2).
A Pt100 temperature probe detects the outflow temperature in the bath. A high-resolution A/D converter processes
the measurement. Further measurement conditioning occurs using a special control algorithm for controlling the heater
actuator and the refrigeration system.
4.7 Refrigeration system
The refrigeration system consists essentially of a hermetically sealed compressor. Heat of condensation and motor heat
are dissipated by a fan-cooled finned condenser. Fresh air is drawn in at the front of the unit; warmed air is discharged at
the back and to the sides. The ventilation openings must not be restricted in order to ensure proper air circulation.
The compressors are fitted with sensors that responds both to the compressor temperature and to the motor current.
Cooling curves (

10 Technical data).
4.8 Standard accessories
All refrigerated RA types are delivered with bath covers and an external circulation set to connect an external circuit.
All heating types A 6, A 12 and A 24 are not supplied with bath covers. Cooling coil, bath cover and external circulation
set can be ordered as accessory (

9).
A pump outflow reducer avoids to spill over liquid in small baths (A 6, RA 8, A 12, RA 12).