How to check and measure the floor temperature sensor?
The NTC floor temperature sensor, used in electric floor heating, is a component that can be damaged. Therefore, it should always be installed properly. For detailed instructions, see the article How to install a temperature sensor in a heating mat?
How to check the floor sensor?
If you don't have to, don't pull the wired temperature sensor out of the grommet (from the floor), measure it first. Often the grommets are improperly made and it is sometimes impossible to reinstall the sensor. There are also cases where the wire sensor is most simply stuck in the adhesive layer with the heating mat. Only when it is found to be defective should it be replaced with a new one. You can buy the sensor in this store.
Before proceeding with the measurement, find out what kΩ value the sensor is. This value is given in the data sheet of the particular thermostat with which it is installed, it is needed to compare the result during the measurement. As standard, a wired NTC temperature sensor is installed in the floor.The value of the sensor is given kΩ, at 25°C.
On the wire you can see the printed value of the sensor 12 kΩ / 25°C
If you do not have the technical data from the thermostat and its sensor, there remains the option of pulling the sensor from the conduit and reading the value printed on it. Although it happens that not on every sensor such information is printed. Example: 12 kΩ at 25°C +/- 0.75°C
How to measure a floor temperature sensor?
To make a measurement, you need a meter called a multimeter with the function of measuring low resistance < 200 kΩ. Connect the terminals of the meter to the isolated wires and compare with the table below.
| Resistance sensor / Temperature | 2 kΩ | 10 kΩ | 12 kΩ | 15 kΩ | 33 kΩ |
|---|---|---|---|---|---|
| 15°C | 2 970 Ω | 15 900 Ω | 18 570 Ω | 22 000 v | 53 470 Ω |
| 20°C | 2 430 Ω | 12 600 Ω | 14 870 Ω | 18 000 Ω | 41 860 Ω |
| 25°C | 2 000 Ω | 10 000 Ω | 12 000 Ω | 15 000 Ω | 33 000 Ω |
| 30°C | 1 670 Ω | 8 030 Ω | 9 750 Ω | 12 000 Ω | 26 210 Ω |
These values may vary minimally depending on the sensor manufacturer.
I bought a floor sensor of a different kΩ value
When replacing the temperature sensor, remember that not every room thermostat will work properly with every wired sensor. Wired sensors have different resistance. Before connecting a new sensor to the thermostat, check its value and check the settings in the thermostat. A room thermostat with a poorly selected or configured floor sensor will read the wrong temperature or will not work with it.
Our floor thermostats are compatible with third-party floor sensors, in addition to the factory included ones. This is a very useful feature to keep in mind before purchasing a controller. For example:
- RAYCHEM R-NRG-DM floor thermostat is compatible with sensors with resistance of 2, 10, 12, 15, 33 kΩ.
- RAYCHEM R-SENZ-WIFI floor thermostat is compatible with sensors with resistance of 2, 10, 12, 15, 33, 100 kΩ.
