S+S Regeltechnik THERMASREG FST-K-HR Notice D'instruction page 7

G
Mounting and Installation
Scheme
Normal
1
operation
Danger
0
of frost
cold
FUNCTION
The switch in the FST-K duct frost protection thermostat responds if the temperature across the entire length of the duct
tube falls below the preset temperature setpoint (closes contact C - 2). Contact C - 3 opens at the same time and can be
used as a signal contact. Resetting occurs automatically (contact closes C - 3) if the temperature rises above the preset
setpoint again (on type FST-K - HR, resetting must be performed manually using the reset button).
The FST-K is "intrinsically safe", i.e., in the event of damage to the capillary tube-membrane system, it automatically
switches to the heating function. Contact C - 2 closes and can therefore be used as an operating contact. The air temperature
is detected over the entire length of the sensor (capillary tube). The gas-filled (R 507) membrane system and the capillary
tube constitute one measuring unit, which is mechanically coupled to the microswitch.
Notes regarding FST-K
A preset setpoint value can be lead-sealed at the adjusting
screw. It is absolutely necessary to ensure that ambient
temperature at the device does not drop below the preset
setpoint temperature.
This device must be operated in a non-precipitating pollutant-
free ambience.
SD
T
w warm
FST-K Connecting diagram
C
2
3
C
C 2
2
3
Rev. 2018 - V12 GB
FST-K
3