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. 331-578A
Mfr. Part No.2455R 82-711 F100C
BrandHoneywell
£4.656
Each (In a Pack of 25)
Units
- - +85°C +100°C - NO 15 A 240 V ac Quick Connect - - - -
RS Stock No. 331-578
Mfr. Part No.2455R 82-711 F100C
BrandHoneywell
£7.14
Each
Units
- - +85°C +100°C Bi-Metallic NO 15 A 240 V ac Quick Connect - - - -
RS Stock No. 253-2773
Mfr. Part No.67L100
£6.72
Each
Units
+40°C +130°C +100°C - Bi-Metallic NC 1 A 48 V dc, 120 V ac PCB Pin - PCB Mount - NC Contact
RS Stock No. 229-5812
Mfr. Part No.2455RP 9100-441 L150C
BrandHoneywell
£5.49
Each
Units
0°C +186°C +150°C +135°C Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 357-7834
Mfr. Part No.602021/0005-064-000-25-1000-40-10-00-00-000-00-6
BrandJumo
£120.73
Each
Units
+50°C +300°C - - Capillary - 20 mA 24 V ac/dc Solder Tab - - - -
RS Stock No. 158-4486
Mfr. Part No.603021/70-1-043-00-0-00-20-13-46-200-8-6/000
BrandJumo
£220.22
Each
Units
+20°C +120°C - - Capillary NC 10 A 230 V ac/dc Screw - - - -
RS Stock No. 229-5963
Mfr. Part No.2455RP 9100-444 F70C
BrandHoneywell
£6.20
Each
Units
0°C +186°C +55°C +70°C Bi-Metallic NO 10 A 250 V ac Solder Tab - - - -
RS Stock No. 158-4420
Mfr. Part No.603021/01-1-025-30-0-00-20-13-46-120-8-6/000
BrandJumo
£170.02
Each
Units
0°C +100°C - - Capillary NO/NC 10 A 230 V ac/dc Solder Tab - - - -
RS Stock No. 454-2227
Mfr. Part No.902150/10-378-1003-1-6-50-11-2500/000
BrandJumo
£54.92
Each
Units
-50°C +180°C - - - - - - - - - - -
RS Stock No. 509-0979
Mfr. Part No.TCM 230V/12V 3VA
BrandEliwell
£14.52
Each
Units
- - - - - - - - - - - - -
RS Stock No. 228-2608
Mfr. Part No.2455RM 9082-470 L100
BrandHoneywell
£8.30
Each
Units
+50°C +150°C +100°C - Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 357-7525
Mfr. Part No.602021/0001-027-000-25-1000-40-10-00-00-000-00-6
BrandJumo
£51.87
Each
Units
0°C +150°C - - Capillary - 0.25 A @ 230 Vdc, 16 A @ 230 Vac 230 V ac/dc Solder Tab - - - -
RS Stock No. 518-4361
Mfr. Part No.602030/01-041-000-70-2000-40-10-6-40-13-460/707,
BrandJumo
£38.74
Each
Units
+20°C +90°C - - Capillary NO/NC 16 A 230 V ac Quick Connect - Wall Mount - -
RS Stock No. 357-9830
Mfr. Part No.608501/2160-926-02-2000-873-6-104-95-46-150-20/000
BrandJumo
£132.97
Each
Units
+50°C +250°C - - Capillary - - - - - - - -
RS Stock No. 229-5806
Mfr. Part No.2455RP 9100-430 L20C
BrandHoneywell
£6.90
Each
Units
0°C +186°C +20°C +10°C Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 253-2694
Mfr. Part No.67F070
£6.75
Each
Units
+40°C +130°C - +70°C Bi-Metallic NO 1 A 48 V dc, 120 V ac PCB Pin - PCB Mount Automatic Close On Rise
RS Stock No. 229-5856
Mfr. Part No.2455RP 9100-438 L100C
BrandHoneywell
£7.28
Each
Units
0°C +186°C +100°C +85°C Bi-Metallic NC 10 A 250 V ac Solder Tab - - - -
RS Stock No. 357-7367
Mfr. Part No.608501/2160-818-02-2000-873-6-104-96-46-150-20/000
BrandJumo
£99.83
Each
Units
0°C +120°C - - Capillary - - - - - - - -
RS Stock No. 494-0867
Mfr. Part No.2455RC-90820388
BrandHoneywell
£5.80
Each
Units
0°C +260°C +160°C - Bi-Metallic SPST NC 15 A 120 → 250 V ac Quick Connect - - - -
RS Stock No. 467-028
Mfr. Part No.603070/0001-6-016-000-25-0-00-15-00-00-000-00-17
BrandJumo
£77.05
Each
Units
-10°C +40°C - - Capillary - - - - - - - -
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