In power applications, AW642 requires a cooled, depressurised sample.
ABB Continuous Water Analysis
Phosphate · AW642 / AW636
Two different applications: phosphate treatment in the steam cycle and phosphate removal in municipal water treatment. Select the technology and range for the application.
Two different applications
AW642 Navigator / AW636 Aztec
AW642 is the Navigator 600 for steam generation and boiler chemistry; AW636 is the Aztec 600 for phosphate removal and municipal wastewater. They are not simply two ranges for the same application.
0–15 ppmAW642 PO₄
1–6 streamsAW642
0–50 ppmAW636
ColorimetricBoth
When to use it / when to consider alternatives
Practical guidance
A good fit when
- AW642 for boiler water and phosphate dosing
- AW636 for municipal effluent and phosphate removal
- multi-stream measurement when sampling points are comparable
- colorimetric analysis for continuous automatic measurement
Consider carefully when
- confusing boiler chemistry with municipal phosphate removal
- sample solids or colour beyond the compensation capability
- inadequate management of reagents and calibration standards
- excessive sample delay relative to process dynamics
Best practice
Installation and maintenance
Check levels, expiry dates and replacement procedures to avoid contaminating the fluidics.
Helps compensate for background effects but does not replace a representative sampling point.
More channels reduce the measurement frequency available for each stream.
Provide an unrestricted drain compatible with the reagents.
Periodically compare readings with laboratory results or standards, according to quality requirements.
SWAS/SCS integration
For high-pressure or high-temperature sampling points, we can integrate sample conditioning, cooling, pressure reduction, flow control and the analyser on the same panel.
Explore integrationBest to know
Useful technical details
AW642
Molybdenum blue method, automatic two-point calibration, 1/2/4/6 streams.
AW636
Phosphomolybdenum blue method, automatic dilution and self-cleaning for municipal applications.
Response time
AW642 analyser T90 is <15 min; the overall plant response always includes sample transport time.
SWAS
For boiler phosphate measurement, the panel must manage pressure, temperature, flow and drainage before the analyser.
AW642 · Boiler / steam generation
Automatic cleaning, calibration and zeroing, multiple streams, reaction temperature control and continuous chemistry monitoring for phosphate treatment.
AW636 · Municipal wastewater
Aztec 600 for optimising phosphate removal and meeting discharge limits; up to three streams, automatic calibration and dilution, and self-cleaning fluidics.
Models and installed base
Models we support
AW642 Navigator 600AW636 Aztec 600
ABB documentation
ABB datasheets and manuals
Download the documents for your model. Shared manuals, protocols and versions are identified in each document card.
AW642 · Navigator 600 Phosphate
Complete operating manuals for single- and multi-stream versions.
AW636 · Aztec 600 Phosphate
The Aztec colorimetric manual covers several parameters; follow the phosphate-specific sections.
Request a quotation
Phosphate · AW642 / AW636
Technical FAQ
Frequently asked questions
AW642 or AW636?
AW642 Navigator 600 is intended for high-purity water, steam generation and boiler chemistry; AW636 Aztec 600 is intended for drinking water, municipal wastewater and phosphate removal.
What is the AW642 range?
ABB specifies 0–15 ppm PO4, with a minimum range of 0–1 ppm.
What is the AW636 range?
ABB specifies 0–50 ppm PO4 for municipal applications.
Why is phosphate important in a boiler?
To verify the phosphate treatment strategy and keep boiler water within target conditions without over- or under-dosing.
How fast is a colorimetric phosphate analyser?
AW642 has a specified T90 below 15 minutes; sample transport delay must be added.