In this guide, we have compiled information on what you should pay attention to when selecting, purchasing, installing and operating your air probe.
What is an air probe?
Air probes are used for air temperature measurements in building automation, heating and air conditioning technology and ventilation technology. The special feature of these probes is that the protection sleeve is perforated. This allows the air to flow around the sensor unhindered, which significantly shortens the response times. The sensor is nevertheless protected from mechanical influences by the protection sleeve.
What should I pay attention to when selecting the right air probe?
What temperature will the probe and cable be exposed to?
To prevent the probe or cable from being damaged, please observe the permissible temperature ranges for the use of the probe and cable. These depend on the measuring element and the cable. You will find the information on this in our data sheet or in the long description of your probe.
How deep should the probe be inserted into the duct?
We recommend a minimum immersion depth of five times the sleeve diameter. You know you have reached a sufficient immersion depth when further immersion no longer results in a change in the indicated temperature. Depending on the required immersion depth, you should choose the length of the protection sleeve. In our online store we offer the protection sleeve in 100 mm and in 200 mm length. If you need a different length, please contact us.
What other requirements do I have for the cable material?
Please check if there are other requirements regarding the cable material in your measuring environment. In some environments, silicone cables may not be used. For some requirements e.g. a PVC cable is too rigid.
An overview of the properties of our cables can be found here --> Cable
In which medium shall be measured?
Please ensure that the probe cannot be damaged by the properties of the medium. Air temperature probes have a perforated protection sleeve, therefore they have only IP20 and must not be used e.g. in humid media. Chemical substances in the gas / air can also damage the probe.
To which device should the probe be connected?
Please check which sensor you need to connect your Air temperature probe to the measuring device. In our online store you can find the following sensors: Pt100 class A, Pt100 class B, Pt100 1/3 class B, Pt100 1/10 class B, Pt1000 class A, Pt1000 class B, Pt500 class B, Ni1000.
Please pay attention if and if yes, which kind of sensor your measuring device / measuring point specifies and please check exactly, if the characteristic curve of the sensor fits to the characteristic curve, which is stored in your measuring device. If necessary, you will find this information in the operating instructions. You can find the characteristic curves of our sensors here in the overview or also in the operating instructions, which you can download for each sensor type.
In addition to the sensor, you should also check how the air probe is to be connected to the measuring device, i.e. which type of connection you require. With us you can order the Pt sensors as two, three or four-wire versions. Please check at your measuring device / at your measuring point, if you need a three-wire or a four-wire. The distance between the measuring point and the measuring device should also play a role in your considerations.
You can find detailed information on the permissible cable lengths here: --> Cable
Should the probe be permanently installed at the measuring point? Do you need mounting material?
Please check whether you may need accessories for the correct mounting of your air probe. In our store you will find the following accessories:
How do I measure the air temperature with an air probe?
Our air probes are quick and easy to use: Hold your probe in the measuring environment. Due to the exposed sensor, your probe will react after a short response time. In order to obtain an optimal measuring result, the probe should be inserted sufficiently deep into the measuring medium and, if necessary, moved back and forth in the air at approx. 1.5 m/s.
Air temperature probe frequently asked questions
How much heat can air probes withstand?
The heat resistance of our air probes depends on two components - the connecting cable (insofar as it can be brought into the measuring range or damaged by heat transfer).
The following temperature ranges apply to our cables.
- PFA: -50 °C to +260 °C
- PVC -30 °C to +105 °C
- Silicone: -50 °C to +180 °C
- Glass fibre: -50 °C to +400 °C
The second component is the sensors, because in the air probes the sensors are not protected from heat by the protection sleeve. Our sensors have different measuring ranges.
- NTC-Sensors& LM235Z up to 125 °C
- For PT sensors it depends on the accuracy class of the sensor
More detailed information about the sensors can be found in the download area and on the respective product pages of the probes.
How can I tell that my air probe is defective?
To avoid measurement errors, please make sure that you insert the air probe sufficiently deep into the medium to be measured, move it slightly if necessary and wait for the response time.
You have followed these steps, but your temperature probe shows strange values? Or the temperature probe does not show any values? This behavior may indicate that your temperature probe is defective or that it has not been connected correctly.
To find out if there is a defect, you can simply measure the resistance value of resistance-based temperature probes and compare it with the specification on the probe itself or in the instruction manual. You can use a standard multimeter to do this.
If you are using a thermocouple instead of a resistance-based temperature probe, the situation is somewhat different. Here you need a multimeter with an appropriate connector for thermocouples, because thermocouples do not have a resistance signal, but a voltage signal.
Alternatively, you can test on a trial basis whether a replacement will remedy the situation.
How do I connect the temperature probe correctly?
When connecting your temperature probe, please make sure that you follow our wiring diagrams. You will find the wiring diagrams in the operating instructions for your temperature probe.