3Wire FBTU2X is a wall-mounted ultrasonic flow meter designed for long-term liquid flow measurement and optional BTU / heat energy monitoring. It uses transit-time ultrasonic measurement technology to measure flow accurately without moving parts.
For IoTWatt 4.0 projects, FBTU2X provides the flow and BTU data needed to analyse chilled water systems, cooling load, chiller COP, pump operation, heat exchanger performance, abnormal flow behaviour and verified energy savings.
Product TypeWall-mounted ultrasonic flow meter with optional BTU measurement
MeasurementTransit-time ultrasonic flow measurement with no moving parts
CommunicationRS485 / Modbus, 4-20mA, pulse and relay outputs
IoTWatt ValueSupports chiller COP, cooling efficiency and BTU analytics
Overview: Flow and BTU Visibility for Cooling and Utility Systems
Flow measurement is essential for understanding chilled water, cooling water, process water and utility system performance. Without flow data, it is difficult to verify cooling output, detect abnormal flow, evaluate pump operation, calculate BTU or understand whether the system is operating efficiently.
FBTU2X provides a practical and cost-effective monitoring solution for long-term liquid flow measurement. With suitable Pt100 temperature transducers, it can also calculate heating or cooling energy using flow rate and supply / return temperature difference.
Key positioning
FBTU2X is best positioned as an ultrasonic flow and optional BTU meter for chilled water systems, HVAC monitoring, plant utilities, process water, energy audits and IoTWatt 4.0 cooling system analytics.
How FBTU2X Supports IoTWatt 4.0 Cooling Analytics
IoTWatt 4.0 can combine flow, temperature and electrical power data to calculate cooling performance, chiller efficiency and system behaviour over time.
1. Flow DataFBTU2X measures chilled water or process water flow.
2. Temperature DataPt100 sensors measure supply and return temperature.
3. BTU / CoolingBTU value supports cooling load and heat energy calculation.
4. IoTWatt 4.0Chiller COP, dashboards, WattMind analytics and reports.
5. ActionOptimise chiller, pump, valve and cooling system operation.
Key Features
UT
Transit-Time Ultrasonic Measurement
Provides accurate and stable liquid flow readings using transit-time ultrasonic flow measurement technology.
BTU
Optional BTU / Heat Energy
With suitable Pt100 temperature transducers, FBTU2X can calculate heat energy from flow and temperature difference.
NM
No Moving Parts
The ultrasonic measurement method has no moving mechanical parts, reducing wear and maintenance requirements.
CO
Clamp-On Option
Clamp-on transducers allow flow measurement without cutting the pipe, water shutdown or pressure loss.
IN
Insertion and Pipe-Type Options
Suitable for permanent installations, larger pipes or applications where clamp-on installation is not ideal.
RS
RS485 / Modbus Communication
Supports integration with PLC, SCADA, BMS, EMS, IoT gateways and IoTWatt 4.0 platforms.
1%
±1% Accuracy
Supports reliable long-term flow measurement for monitoring, reporting and performance analysis.
IP
IP-Rated Protection
Converter protection up to IP67 and transducer protection up to IP68 for demanding environments.
DN
Wide Pipe Range
Supports pipe diameters from DN25 to DN6000, depending on selected transducer and application.
Measurement Options
Flow Measurement
Suitable for chilled water, cooling water, process water, raw water, reclaimed water, plant effluent, potable water, chemical liquids and other compatible liquids.
BTU / Heat Energy Measurement
When paired with Pt100 temperature sensors, FBTU2X can support chilled water BTU monitoring, hot water energy measurement and HVAC energy monitoring.
Long-Term Monitoring
Designed for continuous flow and optional BTU monitoring in industrial, commercial, HVAC and utility applications.
Installation Methods
Installation Method
Description
Best Use
Clamp-On Type
External transducers are clamped onto the outside of the pipe.
Retrofit projects, operating systems, no pipe cutting, no water shutdown and no pressure loss.
Insertion Type
Insertion sensors are installed into the pipe wall.
Larger pipes, permanent installations and applications where clamp-on measurement is not ideal.
Pipe-Type Meter
A dedicated meter pipe section is installed in-line.
Permanent metering points where stable measurement and controlled installation conditions are required.
Installation note
Correct installation depends on pipe material, pipe condition, pipe diameter, straight pipe availability, liquid quality, air bubbles, scaling and the selected transducer type.
Technical Highlights
Item
FBTU2X Specification
Product Type
Wall-mounted ultrasonic flow meter
Measurement Principle
Transit-time ultrasonic flow measurement
Flow / BTU Capability
Flow measurement; optional BTU / heat energy measurement
Accuracy
±1%
Display
2 x 20 character LCD with backlight
Signal Output
4-20 mA output, OCT pulse output and relay output
Signal Input
3-way 4-20 mA input
Temperature Input
Supports Pt100 temperature transducer for heat / energy measurement
Communication
RS485 serial interface, Modbus support
Pipe Diameter
25-6000 mm
Flow Rate
0 to ±7 m/s
Straight Pipe Requirement
Upstream 10D, downstream 5D, 30D from pump
Liquid Type
Water, hot water, chilled water, city water, sea water, waste water, sewage, chemicals, plant effluent, beverage, ultra-pure liquids and others
Medium Temperature
-30°C to +160°C
Converter Operating Temperature
-20°C to +60°C
Flow Transducer Operating Temperature
-30°C to +160°C
Power Supply
DC 8-36 V or AC 85-264 V optional
Power Consumption
1.5 W
Converter Dimension
132 x 150 x 85 mm
Converter Protection
IP67
Transducer Protection
IP68
Optional Transducers
FBTU2X supports different transducer selections based on pipe size, liquid condition, temperature and installation method.
Small clamp-on transducers
Medium clamp-on transducers
Large clamp-on transducers
High-temperature clamp-on versions
Insertion transducers
Pipe-type transducers
Clamp-on temperature transducers
Insertion temperature transducers
Insertion Pt100 transducers
Suitable Liquids
FBTU2X can measure many liquid types. Final application suitability should be checked based on pipe material, liquid condition, temperature, turbidity, air bubbles and installation method.
For chilled water and HVAC systems, flow and temperature difference are required to understand actual cooling output. When FBTU2X is used with temperature sensors, IoTWatt 4.0 can compare cooling output against electrical input to understand system performance.
Monitoring Area
What FBTU2X Provides
IoTWatt 4.0 Value
Chilled Water Flow
Continuous flow data for primary, secondary or process cooling circuits.
Understand flow profile, abnormal flow and system operating behaviour.
BTU / Cooling Load
Flow plus supply / return temperature difference.
Calculate cooling output and compare with chiller power input.
Chiller COP
BTU output data combined with electrical kW input.
Support WattMind chiller efficiency analytics and performance tracking.
Pump Optimisation
Flow trend compared against pump energy and operating schedule.
Identify excessive flow, throttling, bypassing or inefficient pumping behaviour.
Energy Audit Evidence
Flow, BTU and load profile records.
Support digital energy audit reports, savings verification and operational recommendations.
Practical outcome
FBTU2X gives IoTWatt 4.0 the flow and optional BTU data needed to move from “chiller kWh only” to real cooling efficiency analysis.
Typical Applications
HVAC and Chilled Water
Chilled water BTU measurement, cooling system performance monitoring and chiller plant performance analysis.
Industrial Water Flow
Cooling water, process water, plant utility, reclaimed water and plant effluent flow monitoring.
Supports building cooling system analysis, heat exchanger energy tracking and cost centre allocation.
BMS / EMS / SCADA
Connect through RS485 / Modbus to automation, monitoring and energy management systems.
IoTWatt 4.0 Monitoring
Flow and BTU data can be connected to IoTWatt 4.0 for long-term monitoring, analytics and reporting.
Integration with IoTWatt 4.0
FBTU2X can be connected through RS485 / Modbus to IoT gateways and energy management platforms. When integrated with IoTWatt 4.0, flow and BTU data can be combined with power meter data, temperature readings, equipment status and energy cost data.
IoTWatt 4.0 Use
How FBTU2X Supports It
Chiller COP Monitoring
Combines BTU output and electrical input to support chiller efficiency visibility.
Cooling Efficiency Tracking
Analyses cooling performance, abnormal flow and system behaviour over time.
Pump and Flow Analytics
Supports flow profile analysis against pump operation, energy and control schedules.
Digital Energy Audit
Provides flow and BTU evidence for audit findings, savings opportunities and performance verification.
EECA / Energy Reporting
Supports cooling system and utility-level data collection for energy management reporting.
WattSave Savings Verification
Supports before / after verification for chiller tuning, pump optimisation and chilled water improvements.
IoTWatt 4.0 call to action
Use FBTU2X with IoTWatt 4.0 when chilled water, cooling water or process water systems must be monitored for flow, BTU, efficiency, abnormal behaviour and verified savings.
Recommended Deployment Checklist
Confirm liquid type, pipe material and pipe condition.
Confirm pipe diameter and required transducer type.
Confirm flow range, normal flow and minimum expected flow.
Confirm straight pipe availability: upstream 10D, downstream 5D and 30D from pump where possible.
Confirm whether flow-only or BTU / heat energy measurement is required.
Confirm Pt100 temperature sensor type and installation point for BTU measurement.
Confirm required outputs: RS485 / Modbus, 4-20mA, OCT pulse or relay.
Confirm power supply option: DC 8-36V or AC 85-264V.
Confirm IoTWatt 4.0 gateway, register mapping, data interval and dashboard requirement.
The following visuals support the FBTU2X wall-mounted ultrasonic flow meter, transducer connection and product configuration information above.
FBTU2X wall-mounted ultrasonic flow meter
FBTU2X product and connection view
FBTU2X Supply, Sizing and IoTWatt 4.0 Integration
Saturn Pyro supports 3Wire FBTU2X ultrasonic flow meters for chilled water BTU monitoring, cooling system analysis, process water metering, chiller COP analytics, IoTWatt 4.0 digital energy audit projects, EECA reporting data collection and verified savings initiatives in Malaysia.
