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Accessories Pressure switchesPressure transmittersThermostatsTemperature sensorsFlow monitorsSolenoid valves
Mechanical thermostats
General technical information
General technical information
for series TX, TRM and TAM
Adjustment of thermostats at lower switching point
Setpoint xS corresponds to the lower switching point (with falling temperature), the upper switching
point xO (with rising temperature) is higher by the amount of the switching differential xd.
Setting the switching temperature (setpoint adjustment)
Prior to adjustment, the setscrew above the scale must be loosened by approx. 2 turns and
retightened after setting.
The switching temperature is set via the spindle. The set switching temperature is shown by the
scale.
In view of tolerances and variations in the characteristics of sensors and springs, and due to friction in
the switching kinematics, slight discrepancies between the setting value and the switching point are
unavoidable. The thermostats are usually calibrated in such a way that the setpoint adjustment and
the actual switching temperature correspond as closely as possible in the middle of the range.
Possible deviations spread to both sides equally.
Clockwise: low switching temperature
Anticlockwise: high switching temperature
Changing the switching differential (only for switching device TRMV…)
The switching differential is changed by turning the setscrew within the spindle. The lower switching
point is not changed by the differential adjustment; only the upper switching point is shifted by the
differential. One turn of the differential screw changes the switching differential by about 1/2 of the
total differential range.
When adjusting please note:
Switching temperature: Clockwise for lower switching point.
Anticlockwise for higher switching point.
Switching differential: Clockwise for larger differential. Anticlockwise for smaller differential.
Electrical connection
Plug connection to DIN EN175301. Cable entry Pg 11, max. cable diameter 10 mm.
Cable outlet possible in 4 directions spaced 90° apart.
Temperature limiter with reclosing lockout
Additional function ZFT205 and ZFT206: All thermostats can be equipped with a mechanical
interlock. On reaching the value set on the scale, the microswitch trips over and remains in this
position.
The lock can be released by pressing the unlocking button (identified by a red dot on the scale side
of the switching device). The interlock can take effect with rising or falling temperature, depending on
the version.
Mounting position
A vertical mounting position is preferable if at all possible. IP 54 protection is guaranteed with a
vertical mounting position. A different mounting position may alter the protection class, but the
operation of the thermostat is not affected.
Outdoor installation of thermostats
FEMA thermostats can be installed out of doors provided they are mounted vertically and suitably
protected against the direct effects of weather. At ambient temperatures below 0°C, ensure that
condensation cannot occur in the sensor or in the switching device.
Switching temperature
(large screw)
Switching differential
(small screw)