Frost protection thermostat Honeywell
With FT frost protection thermostats, it is neces- sary to ensure that the ambient temperature at the switching device does not fall below the defined switching point. Also, parts of the capillary tube outside the air heater must not be laid in zones whose temperature may fall below the defined switching point. Either situation would cause the device to cut out prematurely.
FEMA frost protection thermostats reliably monitor the temperature in hot-water-heated air heaters. If the temperature falls below the set value, the thermostat switches off. A visual or audible “frost haz- ard” alarm can be switched on at the same time. A fixed stop on the setting spindle at 3°C prevents the thermostat from being set below the freezing point due to inexpert adjustment. If the capillary tube is damaged or broken, FEMA frost protection thermostats reliably switch off towards the safe side (e.g. fan off) irrespective of the temperature at the sensor.
Operating method
FT frost protection thermostats with 3 m or 6 m capillary tube detect the temperature over the whole length of the capillary tube and are therefore able to monitor the surface of the whole air heater. If the capillary tube becomes too cold at any point, the thermostat switches off.
Frost protection thermostats with reclosing lockout (switching unit 206) break the circuit at the set value when the temperature falls. The adopted switching state is mechanically latched against automatically switching on again. The latch can only be released by pressing the unlocking button after the temperature has risen again by approx. 8°C
Body
Diecast aluminium GD, Al Si 12 according to DIN 1725.
Sensor
Cu capillary tube
Max. ambient temperature at switching device
+70°C , +60°C for Ex versions
Contact arrangement
Single-pole changeover switch
Switching capacity
8 (5) A 250 VAC
Degree of protection
IP 54 according to DIN 40050 (with vertical installation)
Switching differential approx.
4 K, preset in factory
Calibration
Scale value corre-sponds to the lower switching point (with falling temperature), the upper switching point is higher by the amount of the switching differential
Plug connection Angled plug, 3-prong+ earth contact, to DIN 43650.Cable entry Pg 11. Max. cable diameter 10 mm, cable outlet possible in 4 directions spaced 90° apart. Supplied with plug