To ensure that the sensor can be replaced in case of failure, the sensor must be installed in a flexible protective tube. Each heating kit from a reputable company includes a protective tube for the floor temperature measurement sensor. Installation of the floor temperature sensor in the protective tube is a necessary step for any heating system and should not be skipped. Floor sensors can sometimes fail. Only the proper installation of the casing pipe will allow you to replace a broken sensor without problems.
Floor temperature sensor
A wired floor sensor should be included with the room thermostat, the most common type: NTC 10K at 25°C. NTC 10K sensors are very versatile, designed for temperature measurement in various fields of construction and industry. The measuring range, accuracy class and dimensions meet the standards used in automation.
What is the floor temperature sensor for?
Heating cables and floor heating mats, according to regulations, must be controlled by a thermostat that regulates the temperature using an external floor temperature sensor. Alternatively, the cables can be controlled by a thermostat that operates in room temperature sensing mode, but with a floor sensor temperature limiter. However, the thermostats themselves must ensure compliance with the Eco Design Directive.
Floor temperature sensor in conjunction with thermostat:
- limits the temperature of the floor – the maximum should be 27°C,
- Protects the user from the discomfort of a hot floor,
- protects the floor from damage – such as wood floors, vinyl floors,
- Protects heating cables from burning out.
How to check if the floor temperature sensor is good?
Whether the floor sensor is good can check with a meter so-called multimeter with the function of measuring low resistance. For this purpose, we do not need to pull it out of the installation pipe, it is enough to measure its value on the wire.
- For most sensors, this will be 10 KΩ at 25°C.
We should find the exact resistance data of the sensor in the installation instructions or in the data sheet of the thermostat. How to measure the floor temperature sensor?
Installation of the temperature sensor in the floor
The floor temperature sensor is installed in a previously installed protective pipe. This tube must be placed directly in the heated floor exactly between the heating conductors of the heating mat or heating cable. This tubing is usually 12 mm thick, which may require partially forcing it into the floor. The sensor must be placed, exactly in the middle between the two heating conductors of the heating cable.
Sensor cover pipe
The pipe found in nVent RAYCHEM heating sets has a high strength and mechanical resistance of 750N. This protects against accidental stronger crushing.
Cap for casing pipe
Before installing the casing pipe in the floor, it should be protected from the side that will be in the layer of glue or screed from getting mortar. In the heating kit, in addition to the casing pipe for the floor temperature sensor, manufacturers often add a cap. The cap should be brass so that it conducts heat better. It should be pressed into the casing pipe included in the kit. Thus assembled components are mounted between the wires of the heating cable.
Replacing the floor temperature sensor
Floor sensors are system components that can fail. In order to be able to remove and reinstall it later, all bends should be made as smooth as possible.
The example below shows the place of the curve between the wall and the floor. Note that the floor in this place (optionally, it can be the wall) is more undercut, which allows the installer to give the pipe the right shape.
Typical installation error of a floor sensor
Never install the sensor diagonally! In this example, the temperature sensor probe may be right under the heating cable which will lead to an incorrect reading of the floor temperature.