Setup mode
Chapter 4
OPERATION MANUAL
V2.2.0en/09.08.21//17.12
Unichiller® eo Desktop
45
4.1.3
Setting the overtemperature protection
The overtemperature protection is not correctly set to the thermal fluid used
MORTAL DANGER FROM FIRE
The overtemperature protection must be correctly set to the thermal fluid you are using.
Always observe the safety data sheet of the thermal fluid.
Different working temperature ranges may apply for open and closed systems.
For Huber thermal fluids:
For Huber thermal fluids, the maximum usable working temperature range is already indicated.
Set the cut-out value of the overtemperature protection to the
upper temperature limit of the
working range
of the thermal fluid.
For thermal fluids of other manufacturers:
Set the cut-out value of the overtemperature protection at least 25 K
below the fire point
of
the thermal fluid.
The maximum settable cut-out value of the OT corresponds, for Huber thermal fluids, to the speci-
fied upper working temperature of the thermal fluid. The usable working temperature range may
be less, if the overtemperature protection is correctly set. When controlling the temperature at
the upper working temperature limit, the OT may be triggered due to tolerances.
4.1.3.1
General information on the overtemperature protection
The overtemperature protection is a device in the temperature control unit that works independent-
ly of the controller. The software and hardware is designed to test key functions and operating
states during a self-test after the power supply has been switched on. If faults are detected, the
enabling of the electrical assemblies in the temperature control unit is blocked. During operation,
the sensors are tested for short-circuit and interruption.
The bath or flow temperature is monitored to ensure the safety of your system. It is set immediately
after you have filled the system with thermal fluid.
Our temperature control units not only offer the possibility to specify the cut-out value of the over-
temperature protection but also provide the possibility to specify the shutdown mode of the tem-
perature control unit. In a typical setting the temperature control unit switches off both the temper-
ature control as well as the circulation
(stop according to DIN EN 61010)
after reaching the cut-out
value. This monitors a possible defect in the control of the heater. A strong exothermic reaction near
the cut-out value can also, under certain circumstances, result in a shutdown of the temperature
control unit. In this case, however, a shutdown would be fatal.
Our temperature control units provide the possibility to work with the shutdown mode
Process
Safety
. In this mode, temperature control (cooling) and circulation work as always. This is therefore
a possibility to respond to exothermic reactions.
The default shutdown mode of the overtemperature protection is
“Stop according to
DIN EN 61010”
. When resetting to factory settings, the overtemperature protection is
reset
to the
default shutdown mode “Stop according to DIN EN 61010”!
Upon delivery, the cut-
out value of the overtemperature protection is set to 35 °C. An alarm is trig-
gered by the temperature control unit shortly after turning on the power if the temperature of the
thermal fluid just filled is higher than the cut-out value set for the overtemperature protection. Set
the overtemperature protection to the thermal fluid you are using.
When setting a new cut-out value for the overtemperature protection, you will be prompted to
enter a randomly generated and displayed code via the numeric keypad displayed. Only after suc-
cessful entry will you be able to change the cut-out value.
