How to check and measure the floor temperature sensor?


The floor NTC temperature sensor, which is placed in the floor between the heating wires in the heating mat, is a component that can be damaged. Therefore, it should always be installed in the right way, as you can read in the article: How to install a temperature sensor in a heating mat?

How to check the floor sensor?

If it is not necessary to remove the wired temperature sensor from the protective pipe that runs to the floor, first measure it. It is often the case that the pipes are incorrectly made and reinstalling the sensor is sometimes impossible. There are also cases where the wire sensor is simply glued to the adhesive layer of the heating mat. Only when it is found to be damaged should an attempt be made to replace it with a new one. Floor sensor can be purchased from this store.

Floor temperature sensor

Before measuring, check what kΩ value the sensor has. This value is given in the data sheet of the specific thermostat with which it is installed, it is needed to compare the result during the measurement. By default, a wired NTC temperature sensor is installed in the floor. The value of the sensor is given as kΩ at 25°C.

NTC temperature sensors
On the wire you can see the printed value of the sensor 12 kΩ / 25°C

If you do not have the technical data of the thermostat and its sensor, you are left with pulling the sensor from the grommet and reading the value printed on it. Although it happens that not on every sensor such information is printed.

How to measure the floor temperature sensor?

Jak zmierzyć czujnik temperatury podłogi?

To make the measurement, you need a meter called a multimeter with a low resistance measurement function < 200 kΩ. Connect the terminals of the meter to the stripped wires and compare with the table below.

sensor /
2 kΩ10 kΩ12 kΩ15 kΩ33 kΩ
15°C2 970 Ω15 900 Ω18 570 Ω22 000 v53 470 Ω
20°C2 430 Ω12 600 Ω14 870 Ω18 000 Ω41 860 Ω
25°C2 000 Ω10 000 Ω12 000 Ω15 000 Ω33 000 Ω
30°C1 670 Ω8 030 Ω9 750 Ω12 000 Ω26 210 Ω
The listed values may vary minimally depending on the sensor manufacturer.

I bought a floor sensor with a different kΩ value

I bought a floor sensor with a different kΩ value

Before buying a new sensor, check the resistance of the sensor that our thermostat supports. Wired sensors have different resistances: 2, 10, 12, 15, 33 and 100 kΩ. A room thermostat with an incorrectly selected or configured floor sensor will read the wrong temperature or display an error.

Some thermostats have the ability to select the sensor. This is a very useful feature and is worth keeping in mind before buying a controller.

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