FL900 Flow Logger
The FL900 Series Flow Logger revolutionizes remote, open channel flow monitoring by providing rugged and reliable innovative solutions for any sewer flow measurement challenge.
FLO-DAR AV Sensor
SKU:
FLOAV
Product Family:
Non‑Contact Open Channel Flow Monitoring for Accurate, Reliable Data
The FLO‑DAR® AV Sensor is a leading non‑contact, open channel area‑velocity flow meter designed to deliver highly accurate velocity and level measurements using advanced ultrasonic sensing—without ever touching the flow. Engineered for demanding environments such as wastewater collection systems, stormwater conveyance, combined sewers, industrial effluent, and agricultural water management, FLO‑DAR provides consistent, dependable flow data even in high solids, shallow, or high‑velocity conditions up to 20 ft/s. By measuring from above the surface, this industry‑proven solution minimizes fouling, reduces maintenance, and ensures reliable performance for applications like I/I analysis, CSO and SSO mitigation, flow‑based billing, capacity planning, and regulatory compliance—helping utilities and engineers lower total cost of ownership while making confident, data‑driven decisions.
Key Benefits and Features
The FLO-DAR AV Sensor is an open channel, non-contact, area-velocity flow monitoring device with ultrasonic level sensing that provides velocity and flow level measurements.
Ideal for applications in:
• Municipal wastewater conveyance/collection systems
• Wastewater treatment plants
• Combined sewer systems
• Stormwater conveyance systems
• Industrial effluent and waste disposal systems
• Irrigation and agricultural water management
Whether you’re dealing with high solids content, extreme temperatures, shallow or caustic flows, large man-made channels, or velocities reaching up to 20 ft/s, the FLO-DAR delivers accurate flow data with unmatched consistency. The FLO-DAR® AV Sensor is a pioneer in non-contact flow monitoring, measuring from above the flow and setting the industry standard for reliability and accuracy. By reducing fouling, minimizing maintenance, and delivering consistent data under both normal and surcharge conditions, the FLO-DAR helps utilities and engineers make confident, data driven decisions while lowering total cost of ownership.
Common Project Uses
• I/I (Inflow and Infiltration) analysis and reduction studies
• Combined Sewer Overflow (CSO) challenges
• Sanitary Sewer Overflow (SSO) challenges
• Collection systems / stormwater systems flow management
• Billing and flow-based cost allocation
• Capacity analysis
• Regulatory compliance and permitting
• Sewer master planning
• Bypass pump and overflow monitoring
• Plant balancing and process control
• Development and engineering studies
Its non-contact design not only minimizes the need for sensor cleaning and maintenance but also enhances safety by reducing personnel’s contact with the flow during installation and maintenance.
In fact, sensor removal or replacement can be done without confined space entry, saving valuable time and reducing operational risks. In the event of a surcharge, where flow levels rise to meet the sensor, the FLO-DAR’s pressure level sensor and optional electromagnetic Surcharge Velocity Sensor ensure that your flow data remains uninterrupted and accurate.
This robust design means less maintenance, fewer operational interruptions, and more reliable data for your analysis. With the FLO-DAR, you’re not just investing in a flow meter; you’re investing in peace of mind and long-term performance. The brilliance of the FLO-DAR lies in its ability to ‘stay out of the flow,’ making sensor fouling—and the data loss that comes with it—a thing of the past.
This sewer flow meter solution houses signal conditioning, communications, data storage, and power functions to support an array of sensors.
*Two-week production time starts when our production facility receives the order. Any missing or technical issues for inputting order information may cause delays. Comprehensive or larger orders are subject to longer production times. Contact your seller or the factory for more information.
• Accurate Flow Measurement
• Non-Contact Sensor Eliminates Lost Data
• Easy Installation and Maintenance
• Independent Accuracy / Long-Term Stability Verification
• Perfect Solution for Difficult Flow Conditions
Accurate Flow Measurement
FLO-DAR provides the user with highly accurate flow measurements under a wide range of flows and site conditions. By measuring the velocity of the fluid from above, FLO-DAR eliminates accuracy problems inherent with submerged sensors including sensor disturbances, high solids content and distribution of reflectors.
Non-Contact Sensor Eliminates Lost Data
No lost data with non-contact, above the flow sensor that is unaffected by fouling due to debris and grease.
Easy Installation and Maintenance
As the sensor is mounted above the flow, personnel have little or no contact with the flow during installation. Future sensor removal and replacement can be done without the need for confined space entry.
The FLO-DAR is commonly installed in tough locations such as:
•Manholes
•Pipes/closed conduits
•Outfalls
•Stormwater, sanitary, and combined sewer culverts
•Gravity sewer pipes
•Storm sewer pipes
•Interceptor and trunk sewers
•Open drainage channels
•Natural channels
•Hydraulic structures such as weirs and flumes
Independent Accuracy / Long-Term Stability Verification
FLO-DAR sensor accuracy and long-term stability (up to 3 years without need for site calibration) from low flow depths up to surcharge conditions has been independently verified many times over the years, including a formal evaluation by the Alden Research Laboratory, Inc. and recent field evaluations done by municipalities and consulting engineering firms.
Perfect Solution for Difficult Flow Conditions
Operates in the most difficult conditions including flows with high solids content, high temperature, shallow and caustic flows, large man-made channels, and high velocities up to 20 ft/s.
Specifications
| Cable | Polyurethane, 0.400 (±0.015) in. diameter; IP68 Standard length
|
|---|---|
| Certifications | FLO-DAR Sensor Model Numbers: 890004801, 890004901, 890004804, 890005201, 890004807, and 890005204 Frequency: 24.10GHz to 24.15GHz Category: Field Disturbance Sensor Output Field Strength: < 2.5 V/m (128dBuV/m) @ 3m, measured per following standards Certified to FCC Part 15.245: FCC ID: VIC-FLODAR24 Certified to Industry Canada Spec. RSS210. V7: IC No.: 6149A-FLODAR24 FLO-DAR Sensor Model Numbers: 890004802, 890004902, 890004805, 890005202, 890004808, and 890005205 Frequency: 24.16GHz to 24.19GHz Category: Short Range Device Output Power (EIRP): < 10mW (10dBm) @ 3m, measured per the following standard Certified to ETSI EN 300 440-1 V1.6.1 (2010-08) |
| Compatible Instruments | FL900 and FL1500 |
| Dimensions | 160.5 W x 432.2 L x 297 D mm |
| Enclosure Construction | IP68 Waterproof rating IP68 |
| Operating Temperature Range | -10 to 50°C (14 to 122°F) |
| Power Supply | Supplied by FL900 Flow Logger, |
| Range Selection | Non Extended Range |
| Set-up/Data Retrieval | FSDATA Desktop Data Management software is used for set-up, data management, and report generation. It is compatible with desktop/laptop computers utilizing Windows operating system. |
| Storage Conditions | -40 to 60°C (-40 to 140°F) |
| Surcharge Depth Method | Piezo-resistive pressure transducer |
| Surcharge Depth Range | 3.5 m (138 in.), overpressure rating |
| Surcharge Velocity Sensor Option | Surcharge Velocity Sensor Included |
| SVS/IS option | Surcharge Velocity Sensor, Intrinsically Safe Option |
| Weight | 4.8 kg (10.5 lbs.) |
| What's included? | Flo-Dar AV Sensor with optional SVS, User Manual |
Filter Downloads
| File Name | Category | Language | Size | Date | Edition | |
|---|---|---|---|---|---|---|
| Data Delivery Services (DDS) : Right Data. Right Results | Brochures | English US | 5 MB | 2024-09 | Sept24 | |
| MCC 25 Flyer FLODAR Flat-Rate-Repair | Brochures | English US | 5 MB | 2025-07 | ||
| FLO-DAR AV Sensor | Data Sheets | English US | 809 KB | 2024-09 | Sept24 | |
| Basic User Manual: Flo-Dar Sensor | Manuals | English UK | 2 MB | Ed7 | ||
| Basic User Manual: Flo-Dar Sensor (English US) | Manuals | English US | 3 MB | Ed7 | ||
| Installation Instruction: Current Generation Flo-Dar Surcharge Velocity Sensor (SVS) Debris Deflector | Manuals | English US | 604 KB | 2024-10 | Ed3 | |
| Instruction Sheet: Laser alignment tool 800012402 for FLO-DAR sensor | Manuals | English US | 391 KB | 2024-10 | Ed3 | |
| Instruction Sheet: Surcharge-Velocity Sensor (SVS) to Flo-Dar Installation | Manuals | English US | 238 KB | 2024-10 | Ed3 | |
| User Manual, Flo-Dar IS Sensor | Manuals | English US | 4 MB | 2024-11 | Ed2 | |
| User Manual, Flo-Dar IS Sensor | Manuals | English UK | 4 MB | 2024-11 | Ed2 | |
| User Manual: Flo-Dar Sensor | Manuals | English US | 2 MB | 2024-10 | Ed8 |
Videos
FLO-DAR AV Sensor Frequently Asked Questions
The FLO-DAR® AV Sensor is a non-contact flow monitoring device that utilizes Doppler radar technology, ultrasonic level sensing, and surface velocity measurements to calculate flow.
Unlike traditional in pipe or submerged flow meters, FLO-DAR measures from above the flow. This eliminates direct exposure to debris and buildup, resulting in lower maintenance, improved reliability, and more consistent data over time.
Positioned above the flow, the Doppler radar sensor emits high-frequency electromagnetic waves at microwave frequencies aimed at the stream of flow, bouncing off irregularities at the air-water interface and returning to the device. A frequency differential occurs due to Doppler shift and this shift is used to calculate the velocity of flow. A simultaneous level measurement is used to determine the cross-sectional area, and this is combined with the velocity measurement to determine the volumetric flow rate.
The FLO-DAR’s ultrasonic level sensor emits ultrasonic sound waves which travel down to the surface of the flow, bouncing back and measuring the time it takes for the sound pulse to return. The sensor then uses that information to calculate the distance correlating to the flow level.
Non-contact flow monitoring offers several key benefits:
• Reduces fouling and sensor maintenance
• Improves long term measurement reliability
• Performs well in high solids or corrosive environments
• Minimizes downtime and total cost of ownership
FLO-DAR is extremely safe due to the contactless nature of the technology. Minimal sensor cleaning and maintenance is needed compared to traditional submerged sensors, enhancing safety by reducing personnel contact with the flow. After initial product installation, all future sensor removal and replacement can be done without the need for confined space entry.
The FLO-DAR is a McCrometer product and is manufactured at Hach’s factory facilities in Loveland, Colorado. Existing under the parent company umbrella of Veralto, McCrometer and Hach are sister operating companies. McCrometer acquired Hach’s open channel line of flow products in 2023, expanding McCrometer’s municipal flow portfolio and establishing a more holistic product suite to meet the sophisticated needs of drinking water and wastewater flow applications.
Hach continues to manufacture FLO-DAR and other open channel products as a contracted manufacturer for McCrometer, to maintain already efficient and effective product fulfillment.
McCrometer’s technical support and field service technicians service the FLO-DAR and other open channel products. Additionally, McCrometer’s authorized representatives and resellers are trained to install and perform maintenance on McCrometer flow products.
Yes. FLO-DAR is designed to perform accurately in challenging environments, including high solids content, shallow flows, caustic conditions, and high velocities up to 20 ft/s. Its non-contact design prevents clogging and performance degradation.
Yes! The FLO-DAR is well-suited for tough applications in wastewater conveyance systems, such as sewers, in manholes, trunk sewers or interceptors, sub-basin outlets, and more. The FLO-DAR easily tolerates turbulent flows, surcharging conditions, debris, and changing velocities.
Yes! The FLO-DAR can be installed under bridges, in culverts, stormwater channels and creeks, river crossings and outfalls, and other outdoor locations. The extended-range FLO-DAR transducer provides precision accuracy for long measurement distances, such as under bridges, up to 20 feet.
Backed by quality engineering and manufacturing, the FLO-DAR’s reliability lies in its ability to measure from above the flow. Area-velocity sensors are typically installed in the flow stream and are at least partially submerged during normal operation. This can lead to fouling, the need for more frequent maintenance, and the possibility of data disruption. The FLO-DAR gives users peace of mind, data integrity, and a more hands-off operation, including less frequent maintenance.
Yes. FLO-DAR provides reliable, consistent flow data that supports regulatory compliance, including applications like CSO and SSO monitoring, I/I analysis, and flow based reporting and permitting.
Yes. FLO-DAR is known for delivering highly accurate and repeatable measurements by combining advanced velocity sensing with precise level detection, even in dynamic or surcharged flow conditions.
By eliminating contact with the flow, FLO-DAR avoids issues like sensor fouling, clogging, and corrosion. This reduces cleaning frequency, minimizes field visits, and lowers overall maintenance costs.
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