Hefer WHA Series Online Water Hardness Analyzer (WHA-3000-C / WHA-2000)

The Hefer WHA series is an online water hardness analyzer family: the WHA-3000-C is a complete panel analyzer for 0.1-999 ppm CaCO₃ and the WHA-2000 is the ion-selective electrode (ISE) hardness sensor. The analyzer is designed for potable water, drinking water and water treatment applications such as softeners and reverse osmosis (RO) systems, and it sends the reading through an isolated 4-20 mA output. As the Hefer distributor in Turkey, Mikron Proses (Üsküdar, Istanbul) handles selection, supply, commissioning, field calibration and service of WHA-3000-C analyzer panels and replacement WHA-2000 ISE sensors.

By monitoring total water hardness (CaCO₃) in real time at the outlet of a softener, in RO pretreatment lines and in boiler feed water, the analyzer is meant to catch the moment a softener resin reaches saturation and starts to leak hardness, which protects RO membranes and boiler tubes against scaling.

WHA-3000-C analyzer and WHA-2000 sensor compared

The table separates the parameters of the complete analyzer panel (WHA-3000-C) from those of the sensor element (WHA-2000), as given in the manufacturer’s datasheets and manuals.

Parameter	WHA-3000-C complete online analyzer (IC-3000 panel)	WHA-2000 hardness sensor (replacement / OEM electrode)
Measuring range (datasheet)	0.1 - 999 ppm CaCO₃	0.4 - 40,000 ppm Ca²⁺ (datasheet) / 0.2 ppm Ca/Mg to saturated solution (technical notes)
Controller display scale	0.01 - 1000 ppm (10.00 / 100.0 / 1000 ppm autoranging)	Depends on the connected controller (IC-3000 or a compatible controller with mV input)
Resolution, accuracy, repeatability	Resolution 0.01 / 0.1 ppm; accuracy ±5% of the reading	Repeatability ±2%; slope 25 ± 5 mV between 10 and 100 ppm (25°C)
Response time, isopotential point	-	95% of the reading in 30 seconds (above 10 ppm); isopotential point 1 ppm Ca/Mg
Working pressure	Process inlet 0.5 - 10 bar	0 - 2 bar at the sensor
Sample temperature and pH	Water 0 - 40°C (acrylic cell 0 - 50°C)	0 - 40°C; pH 5 - 10 (a 1°C temperature change can cause a deviation of up to 2%)
Sample flow and connections	10 - 100 L/h adjustable acrylic sample cell (6 mm inlet / 12 mm outlet)	12 mm diameter, 110 mm length; needs a steady flow without air bubbles
Outputs and enclosure	Isolated 4-20 mA (or 0-20 mA), dry-contact relays, IP-65 (350 × 350 × 180 mm)	mV signal with 100 MΩ resistance (to the controller input)
Sensor life	-	About 1 - 2 years, depending on use and water conditions

Sources: hefer-wha-3000c-datasheet.pdf, hefer-wha-3000c-kullanim-kilavuzu.pdf, hefer-wha-2000-sertlik-sensoru-datasheet.pdf and hefer-wha-2000-sertlik-sensoru-aciklamalar-kilavuzu.pdf.

Sample conditions, chemical limits and field calibration

For the ISE membrane to work accurately and last, the sample water has to stay within these limits:

1. Oxidizing agents and organics: use the sensor in aqueous solutions only. Free chlorine, ozone and organic solvents can damage the sensor membrane permanently, and free chlorine in the sample must be below 0.1 ppm.
2. Complex formation: sulfate, bicarbonate and carbonate ions form complexes with free calcium and magnesium and can shift the reading. Sulfate (SO₄²⁻) should be below 50 ppm and carbonate / bicarbonate below 280 ppm.
3. Cation interference (10% deviation thresholds, WHA-2000 technical notes, Table 1): at a total hardness of 10 ppm CaCO₃, the concentrations that cause a 10% deviation are Cu²⁺ 1.9 ppm, Zn²⁺ 1.95 ppm, Fe²⁺ 3.3 ppm, Ni²⁺ 5.7 ppm, Sr²⁺ 35 ppm, Ba²⁺ 82.2 ppm, Na⁺ 660 ppm and K⁺ 3,909 ppm. If a deviation appears after exposure to such ions, the sensor can be rested in deionized water; long exposure can cause irreversible damage.
4. Installation and routine calibration:
   • Installation calibration (2-point program): take one sample of raw water (before softening) and one from the softener or RO outlet, check their hardness with a hardness test, and enter the values. For higher accuracy, 2 to 5 points can be taken from 0.10 / 1 / 10.00 / 100.0 / 1000 ppm standard solutions.
   • Routine field calibration (one point): a 3-way valve on the acrylic sample cell supplies soft and hard water, and a one-point reference correction takes no longer than 2 minutes.

When the response time becomes much longer or the calibration slope (25 ± 5 mV between 10 and 100 ppm at 25°C) drops, the WHA-2000 sensor is replaced.

Related pages

• Hefer brand page
• Hefer 2030 series transmitters
• Online measurement and automation systems