Introduction
OPERATION MANUAL
Chapter 1
Heat Transfer Station eo
V2.3.0en/22.04.20//17.12
16
1.4.2
Safety devices to DIN 12876
The rating of your temperature control unit is stated on the data sheet in the appendix.
Classification
Temperature
control medium
Technical requirements
Identification
d)
I
Non-combustible
a)
Overheat protection
c)
NFL
II
Combustible
b)
Adjustable overheat protection
FL
III
Combustible
b)
Adjustable overtemperature protection
and additional low-level protection
FL
a)
Usually water; other fluids only if non-combustible even within the temperature range of an individual fault.
b)
The temperature control media must have a fire point of ≥ 65 °C.
c)
The overheat protection can, for instance, can be realized using a suitable fill level sensor or a suitable temper-
ature limiter.
d)
Optional at the choice of the manufacturer.
Overtemperature protection
(for temperature control units with heating)
Mechanical tools are no longer required for setting the trip values for the overtemperature protec-
tion. A software tool is used instead. The threshold value for the overtemperature protection can be
set only if a code randomly generated by “Pilot ONE” beforehand is entered correctly. As with the
mechanical tool, accidental settings are thus prevented. The type of overtemperature protection
function and of low level protection depends on the temperature control unit.
Process safety
This type of overtemperature protection is driven by a desire for further protection of operator and
system. Protective devices typically disconnect all poles when reaching the overtemperature protec-
tion trigger value. This may result in more heat being fed into the process (e.g. exothermic reaction)
than the existing cooling machine is able to cool as the overtemperature protection trigger value is
usually set above the controller setpoint. Turning off the temperature control unit eliminates the
possibility to extract heat from the process. The temperature could therefore rise further and sys-
tem components could be heated up above their rated temperatures, e.g. could cause danger to life
and limb by rupture of the material or phase transitions from liquid to gaseous state. Reaching the
trigger value is recognized in the
Process Safety
mode by the controller at the overtemperature
protection, which then releases cooling. Even if the temperature continues to rise, the cooling ma-
chine will use its maximum cooling capacity to keep any further increase in temperature as low as
possible. You must observe page 43 of section
»Setting the overtemperature protection«
.
Rating of laboratory
thermostats and
laboratory baths
Overview of the tem-
perature thresholds
