WaterBoy measuring case

The electrical conductivity of the heating water provides information about the amount of dissolved salts and minerals. Excessively high conductivity can lead to corrosion and limescale build-up. Measuring this is very easy with our WaterBoy dual-purpose meter.

• Recommended range: Depending on the manufacturer and heating system, the conductivity should be < 100 µS/cm for low-salt systems and < 1,500 µS/cm for high-salt systems.


• Modern heating systems: A low conductivity of less than 100 µS/cm is recommended, particularly for aluminium heat exchangers, to minimise the risk of corrosion.


• DIN EN 14868 and VDI 2035: These standards provide guidance on permissible values, with a value below 100 µS/cm being ideal for many systems.

Conductivity is measured using a conductivity meter, such as the UWS WaterBoy. Here’s how:

• Prepare the meter: Calibrate the device using the WaterBoy app (if necessary) and switch it on.


• Rinse the measuring probe thoroughly with heating water.


• Take a water sample: Take a clean sample from the heating circuit.


• Take the measurement: Immerse the measuring probe in the water and read the value.


• Interpretation: If the value exceeds the recommended levels (see VDI guidelines), softening or desalination of the heating water may be necessary.

The pH value is crucial for corrosion protection:

• Optimal range: The pH value should be between 8.2 and 10. If aluminium components are installed in the system, VDI 2035 even specifies a pH range of only 8.2–9.


• Why not lower? A pH value below 7 means that the water is acidic, which promotes corrosion of metal parts.


• Why not higher? A pH value that is too high can also lead to deposits and damage to certain materials (e.g. aluminium).


• Measurement: The pH value can be determined using our digital WaterBoy meter.


• The UWS Vadion pH-Control mixed-bed resin ensures automatic and accurate pH adjustment.

An app like the WaterBoy app makes it much easier to measure, calibrate and document water parameters.

The benefits:

• Documentation and comparison of measured values over extended periods


• Easy operation and data storage


• Assistance with the important calibration process


• Support in interpreting measurement results


• Clear log as a basis for evidence

Yes, conductivity meters should be checked regularly every 14 days using a calibration solution. pH meters should be checked every 5 days. This is very easy to do with the WaterBoy app.

• Temperature: Higher temperatures increase conductivity. The UWS WaterBoy has automatic temperature compensation (ATC).


• Measurement errors: Residue on the probe or uncalibrated devices can produce incorrect readings.

Yes, there are multifunction devices that measure several parameters (pH, conductivity, TDS). These are useful for comprehensive analyses. The UWS WaterBoy dual-measurement device, which comes with an app, measures pH, conductivity, TDS (Total Dissolved Solids), salinity, temperature and specific resistance.

Common sources of error include:

• Dirty probes: These affect the measurement results. Important: Rinse the probe with plenty of heating water before taking a measurement


• Incorrect calibration: Particularly important for pH and conductivity meters. That is why the UWS WaterBoy is calibrated with pinpoint accuracy via the app


• Air bubbles in the meter: Can produce incorrect readings (e.g. in conductivity probes)

• Prepare the pH calibration solutions 4.01, 7.01 and 10.01 included in the UWS measurement kit in calibration vessels.


• Rinse the measuring probe with distilled water and connect the WaterBoy to the app.


• In the UWS WaterBoy app, click on ‘Calibrate’ in the pH tab and then follow the instructions.


• Important: Always rinse the measuring probe thoroughly with distilled water before immersing it in a new calibration solution.


• Follow the same procedure when calibrating conductivity.


• The UWS WaterBoy app will alert you if the calibration was performed too long ago and will also note this in the log.

According to VDI 2035, these parameters must be documented in order to ensure the quality of the heating water and to prevent damage caused by corrosion or deposits.

The values obtained should be recorded in a logbook or a digital record, such as with the WaterBoy. The date, time, measuring device and the person who carried out the measurement must be documented.