Thermostatic Switches

Thermostats are used in temperature control systems regulating air or liquids and can be used in both commercial and domestic applications. The two main types are capillary and bimetallic thermostats.
RS Components offer a range of thermostats such as enclosure thermostats, mechanical HVAC thermostats, digital and programmable HVAC thermostats, digital and smart thermostats with Wi-Fi.

What Does a Thermostat Do?
It regulates the temperature of a liquid in a tank, or in conjuction with air conditioning units to monitor the air in a room/system. The thermostat simply switches the system off or on whenever necessary so that a constant temperature can be maintained. At home room thermostats switches on the heating when the room is cold and once the temperature has reached the level set, the programmable thermostat switches the heating off.

Capillary Thermostats
These consist of a sensor, capillary tube, diaphragms, a probe and an expansion medium. When the liquid heats up and expands, the temperature sensor is heated allowing for it to be converted into displacement in the diaphragm. The contacts within the closed circuit system can be opened or closed by this displacement due to pressure.
Due to their accuracy and easy installation, they are widely used to control air and water temperatures and are suitable for use in storage heaters, hot tanks and boilers to control hot water.

Bimetallic Thermostats
These consist of a strip of two different metals with different coefficients of linear expansion. The bimetallic strip acts as an electric contact breaker in an electric heating circuit. When the desired temperature is reached, the circuit is broken.
The strips of metal are bolted together. A bridge is then created in the electrical circuit and is connected to your heating system. The strip carries electricity through the circuit when the heating is on. When the strips get hot, both of the metals expand but one more so than the other. The hottest metal bends and opens the circuit. Once the circuit is open the electricity switches off and the heating cuts out.
Once the heating is off, the room cools down which in turn cools down the strip of metal and allows it to go back to its original shape. When it cools, the metal goes back into the circuit and switches the heating back on as the electricity flow has been re-established. The metal strip takes a while to expand and contract so the heating is not constantly switching on and off every few seconds.

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Description Price Minimum Temperature Maximum Temperature Opening Temperature Closing Temperature Thermostat Type Switch Configuration Contact Rating Contact Voltage Rating Terminal Type Hazardous Area Certification Mounting Type Reset Type Switch Function
RS Stock No. 733-4710
BrandRS Pro
£20.20
Each
Units
0°C +120°C - - Capillary SPDT 15 A 250 V ac - - Panel Mount - -
RS Stock No. 733-4723
BrandRS Pro
£20.14
Each
Units
0°C 90°C - - Capillary SPDT 16 A 250 V ac - - Panel Mount Automatic -
RS Stock No. 339-308A
Mfr. Part No.2455R 82-195 L70C
BrandHoneywell
£4.656
Each (In a Pack of 25)
Units
0°C +150°C +70°C +55°C - SPST 15 A 240 V ac Quick Connect - - - -
RS Stock No. 339-308
Mfr. Part No.2455R 82-195 L70C
BrandHoneywell
£7.09
Each
Units
0°C +150°C +70°C +55°C Bi-Metallic SPST NC 15 A 240 V ac Quick Connect - - - Open On Rise
RS Stock No. 228-2636
Mfr. Part No.2455R 9082-462 L50C
BrandHoneywell
£7.09
Each
Units
- - +50°C - Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 733-4735
BrandRS Pro
£21.90
Each
Units
+90°C +110°C - - Capillary SPDT 16 A 250 V ac - - Panel Mount Manual -
RS Stock No. 733-4729
BrandRS Pro
£20.30
Each
Units
0°C +300°C - - Adjustable Capillary SPDT 16 A 250 V ac - - Panel Mount Manual -
RS Stock No. 339-314A
Mfr. Part No.2455R 82-191 L100C
BrandHoneywell
£4.656
Each (In a Pack of 25)
Units
- - +100°C - - NC 10 A 250 V ac Quick Connect - - - -
RS Stock No. 339-314
Mfr. Part No.2455R 82-191 L100C
BrandHoneywell
£7.14
Each
Units
- - +100°C - Bi-Metallic NC 10 A 250 V ac Quick Connect - - - -
RS Stock No. 228-2513
Mfr. Part No.2455RM 9082-468 L70C
BrandHoneywell
£8.30
Each
Units
0°C +150°C +70°C - Bi-Metallic - 10 A - Quick Connect - - - -
RS Stock No. 339-291A
Mfr. Part No.2455R 82-196 L40C
BrandHoneywell
£4.656
Each (In a Pack of 25)
Units
- - +40°C - - NC 10 A 250 V ac Solder Tag - - - -
RS Stock No. 339-291
Mfr. Part No.2455R 82-196 L40C
BrandHoneywell
£7.09
Each
Units
- - +40°C - Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 331-528
Mfr. Part No.2455R 82-716 L90C
BrandHoneywell
£7.09
Each
Units
0°C +150°C +90°C +75°C Bi-Metallic SPST NC 10 → 15 A 240 V ac Quick Connect - - - -
RS Stock No. 331-528A
Mfr. Part No.2455R 82-716 L90C
BrandHoneywell
£4.702
Each (In a Pack of 25)
Units
0°C +150°C +90°C +75°C - SPST NC 10 → 15 A 240 V ac Quick Connect - - - -
RS Stock No. 733-4726
BrandRS Pro
£19.72
Each
Units
+40°C +210°C - - Capillary SPDT 16 A 250 V ac - - Panel Mount Automatic -
RS Stock No. 733-4713
BrandRS Pro
£20.47
Each
Units
0°C +40°C - - Capillary SPDT 16 A 250 V ac - - Panel Mount Manual -
RS Stock No. 228-2557
Mfr. Part No.2455R 9082-464 F50C
BrandHoneywell
£6.99
Each
Units
- - +35°C +50°C Bi-Metallic SPST-NO 10 A 250 V ac Solder Tab - - - -
RS Stock No. 228-2529
Mfr. Part No.2455RC 9082-467 L250
BrandHoneywell
£7.67
Each
Units
0°C +260°C +250°C +210°C Bi-Metallic SPST NC 15 A 120 → 250 V ac Quick Connect - - - -
RS Stock No. 331-540
Mfr. Part No.2455R 82-713 F60C
BrandHoneywell
£7.14
Each
Units
- - +45°C +60°C Bi-Metallic NO 15 A 240 V ac Quick Connect - - - -
RS Stock No. 229-5890
Mfr. Part No.2455RP 9100-434 L60C
BrandHoneywell
£7.01
Each
Units
0°C +186°C +60°C +45°C Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
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