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Unit description
A Pt 100 temperature probe is used for measuring the actual temperature and for control. A second Pt
100 serves as temperature probe for the safety circuit (overtemperature protection) which is independent
of the control function
A low-level protection switches off the heating on both poles in order to prevent dry operation of the
heater. The pump is switched off electronically. The overtemperature switch-off point is adjusted with a
tool on a potentiometer and is always limited to 5 °C above the operating temperature range. A floating
contact "Combination fault" is available (
All settings and fault messages are stored in the memory in case of a supply failure or when the mains
switch is set to OFF.
The tubular heater is controlled from a modified PID controller through a triac circuit specially designed to
be unaffected by supply variations and interference.
3.4
Programmer (Types RE 3xx only)
Types RE 3xx incorporate a programmer which can be used to run temperature programs with up to 20
temperature-time-segments (
3.5
Materials
All parts which come into contact with the bath liquid are made from high-grade materials appropriate to
the operating temperature. These are rust-free stainless steel, PPS plastics and fluoride rubber.
3.6
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.
At working temperatures below approx. 30 °C the refrigeration system operates continuously to
remove a certain amount of heat, with the heater acting in opposition to provide automatically
controlled heating power.
The compressors are fitted with a temperature monitor which responds both to the compressor
temperature and to the motor current. In addition the cooling system is protected against excessive
pressure by a pressure monitor. The refrigeration unit is switched on either automatically or
manually through the operating menu .(
Types RE 207, RE 212, RE 220 as well as RE 307, RE 312 and RE 320 are additionally provided
with a cooling capacity adjustment which saves energy in many operating situations, reduces the
load on the refrigeration system and produces a better temperature control. This feature, too, can be
operated either automatically or manually.
Cooling curves (
10.08.99
YACE0060
Section 6.5.4.).
Section 6.4.4).
Section 6.4.1.).
Section 9. Technical data)
5
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