Temperature Sensors in Household Appliances

Welcome to the second part of our article about temperature sensors. As we have already written in the previous article, household appliances can be divided due to their size and applications:

• Large appliances – washing machines, clothes dryers, dishwashers, refrigerators and freezers, ovens and ovens,
• Small appliances – coffee makers, induction hobs, irons and ice makers,
• Heating devices – heaters, radiators, fans and air conditioners.

Examples of household appliances with temperature sensors (large dimensions)

Washing machines – The temperature sensor in washing machines allows precise control of the water temperature.

Fig. 1. The temperature sensor in washing machines allows precise control of water temperature (K276, Z276, Z277, Z278). In clothes dryers temperature sensors determine the temperature of hot air flowing into the drum (Z509, K514, K524) and that of the vented air (K276, Z276, Z901, Z277). To optimize anti-wrinkling treatment of laundry a temperature sensor can be integrated in the steam generator (K504, K514, K1560, K560)

Examples of temperature sensors in washing machines:

Fig. 2. Examples of temperature sensors in washing machines

Overall specification of  washing machine’s temperature sensors:

• NTC thermistor in a stainless steel housing,
• Suitable for corrosive environments (water with suds),
• K276 meets the standards of water temperature sensors in washing machines,
• Temperature range: from -10 to 100° C,
• Long-term stability,
• Possibility to adapt the sensor construction to specific needs.

Dishwashers – The temperature sensors in the dishwashers are used to measure the water temperature. The injection controller (an electronic device that manages the engine’s power system) retrieves information from the sensor to regulate (in a closed loop) the water temperature for each given dishwasher program.

Fig. 3. Temperature sensors are used to measure the water temperature (K276, Z276, Z278, Z606, K504). The ECU (Electronic Control Unit) uses the information from the sensor for closed-loop regulation of the pre-defined water temperature for each step in the dishwasher program

Examples of temperature sensors in dishwashers:

Fig. 4. Examples of temperature sensors in dishwashers

Overall specification of  dishwasher’s temperature sensors:

• NTC thermistor placed in a specially formed, plastic housing,
• The housing is resistant to moisture and water,
• Possibility to adapt the sensor construction to specific needs,
• Temperature range: from 0 to 85 ° C.

Refrigerators and freezers – Temperature sensors in refrigerators and freezers measure the temperature of the cooling chamber, protect against ice build-up of the evaporator, support the formation of ice cubes and detect the ambient temperature.

Fig. 5. Temperature sensors in refrigerators and freezers measure temperature of cooling compartment, guard against icing in the evaporator, and support ice cube preparation (M2000 and M3000 series, M1005), as well as detecting ambient temperature (M500)

Examples of temperature sensors in refrigerators and freezers:

Fig. 6. Examples of temperature sensors in refrigerators and freezers

Overall specification of  refrigerator’s and freezer’s temperature sensors:

• NTC thermistor placed in a specially formed, plastic housing with cable outlet,
• High resistance to moisture and water,
• Double insulated power cable (M2025), individually (M2010, M1005),
• Possibility to adapt the sensor construction to specific needs.

Examples of household appliances with temperature sensors (small dimensions)

Temperature sensors are also used in household appliances such as: irons, coffee and tea makers, electric kettles, toasters, rice bowls, bottle warmers, icemakers, electric grills and tourist ovens (K504, K514, K524, M703, K560, K1560, M1703 , K302, K45). These devices save more energy, are safer and more convenient to use.

Examples of temperature sensors in household appliances of small dimension:

Fig. 7. Examples of temperature sensors in household appliances of small dimension (NTC thermistors with different housings)

Other devices containing temperature sensors

Heating devices – Temperature sensors are integrated in them at various points in the water heating circuit, in the boiler, in the inflow/outflow of hot water, in the chimney, in hot water tanks and in control devices/thermostats to measure the room temperature.

Fig. 8. Temperature sensors are integrated at various points in a heating system – in the forward and return flow of heating water or in the boiler, in the inflow and outflow of domestic hot water, in the exhaust to measure flue gas, in hot water tanks, in control units and thermostats to meter room temperature. In addition, pressure sensors can also serve to measure refrigerant pressure in heat pumps

Examples of temperature sensors in heating devices:

Fig. 9. Examples of temperature sensors in heating devices (NTC thermistors with different housings)

Air conditioners – Sensors measure the temperature on the evaporator, preventing it from icing. They also measure the temperature at the air outlet or in the room.

Fig. 10. Sensors measure temperature on the evaporator to prevent icing, on the air outlet or in the room

Examples of temperature sensors in air conditioners:

Fig. 11. Examples of temperature sensors in air conditioners

Overall specification air conditioner’s temperature sensors:

• Copper housing well dissipating heat (K500),
• Measuring the temperature on the evaporator (K500),
• NTC thermistor in an epoxy casing (M500, M800),
• Increased resistance to moisture (M800),
• Possibility to adapt the sensor construction to specific needs.

Source: TDK Electronics