Series-TDFS2

Flow Switch, LED Indicators, Adjustable Flow Rate, NO/NC Outputs

Better reliability and life expectancy than mechanical flow switches with no paddles or vanes to wear or break, no jams in the paddle movement, and no seals on movement assembly to wear or leak
Long operation life, as it is not affected by empty pipe by avoiding overheating with heating above the process temperature and then cooling down to process temperature
Lower system run cost due to low pressure drop with 10% insertion into the flow (e.g. 1/8" for 3/4" schedule 40 pipe)

See Product Overview

Series-TDFS2

From ^€ 387,76

Shop Models

1 Variations available

See all series options below

Data Sheet

Product Overview

Applications Boilers, Fluid Measurement and Control, Oil, Refrigeration, Refrigeration Equipment
Deadband 0.1 fps ± 15 %
Deadband Note 0.1 ft/s (0.03 m/s) +15% of setpoint
Enclosure Material 316 Stainless Steel, Stainless Steel, Polycarbonate, Neoprene
Enclosure Ratings IP65, NEMA Type 4X
Input Power and Protection 0.5A Fuse (resettable) Reverse Polarity Protected
Media Compatibility Clean process / cooling water
Operating Temperature, Max 140 °F
Operating Temperature, Min 5 °F
Power Consumption Average: 93 mA, Peak: 300 mA
Pressure Limits Up to 300 psi
Measurement Pressure Type Gauge
Process Connection Size 1/2 in
Process Temperature, Max 140 °F
Process Temperature, Min 5 °F
Repeatability 0.07 fps + 3%
Repeatability Note 0.07 ft/s (0.02 m/s) +3% of setpoint
Response Time 8 s
Sensor Material 316 Stainless steel
Series ID Series-TDFS2
Storage Temperature, Max 185 °F
Storage Temperature, Min -40 °F
Supply Power Type DC
Supply Voltage 9 to 24 Vdc
Switch Note 400 mA, derate 5 mA/°C above 23°C
Switch Rating 400 mA
Switch Type NPN NO, NPN NC
Switched Output Protection 0.5A Fuse (resettable) Reverse Polarity Protected
Velocity, Max 10 ft/s
Velocity, Min 0.5 ft/s
Wire Gauge 22 AWG

Supported Applications

The Dwyer Series TDFS2 Thermal Dispersion Flow Switch indicates whether the flow rate is above or below a user-set flow rate. The series is designed for service with compatible water-based fluids and provides visual status indication via two LED indicators.

Operating Conditions & Performance

The switch operates within an ambient temperature range of 5 to 140°F (-15 to 60°C) and a process temperature range of 5 to 140°F (-15 to 60°C). Storage temperatures are rated from -40 to 185°F (-40 to 85°C). The device supports a pressure rating of 300 psig (20.67 bar) and features a response time of approximately 8 s.

Performance specifications include:

Set Point Range: 0.5 to 10 ft/s (0.15 to 3.0 m/s)
Repeatability: 0.07 ft/s (0.02 m/s) +3% of setpoint
Hysteresis (Typical Deadband): 0.1 ft/s (0.03 m/s) +15% of setpoint
Power Requirement: 9-24 VDC with a switching current of 400 mA, derated 5 mA/°C above 23°C.

The unit incorporates input power and switched output protection via a 0.5 A resettable fuse with reverse polarity protection.

Configuration Options

The Series TDFS2 is configurable across multiple dimensions to accommodate specific installation requirements, including pipe size, electrical connection type, cable length, and process connection standards.

Pipe Sizes: Available in two ranges: 1/2" (15 mm) to 1-1/2" (40 mm), or 2" (50 mm) to 10" (250 mm).
Process Connections: Model selectable as 1/2" NPT male or BSPT male.
Electrical Connections: Options include a 1/2" female NPT with PVC cable for conduit connection, or a cable gland with burial rated cable or PVC jacketed cable. The standard electrical lead is a 4 conductor 22 AWG cable available in lengths from 3 ft (0.91 m) to 50 ft (15.24 m).
Outputs: Provides both 1 NO NPN and 1 NC NPN outputs.
Housing Materials: Constructed with 316 SS, 416 SS, polycarbonate, neoprene, and acrylated urethane. Wetted materials are specified as 316 SS.
Enclosure Rating: NEMA 4X (IP65).

The setpoint is field-adjustable using an included magnet; replacement magnets are available under part number 100571-00. The series offers lower system run cost with low pressure drop due to a design featuring only 10% insertion into the flow.

Key Product Differences

The Series TDFS2 distinguishes itself from mechanical switches by utilizing thermal dispersion technology, eliminating paddles or vanes that can wear, break, or jam. The unit is designed to avoid overheating in empty pipe conditions by heating above the process temperature and then cooling down.

Model variations are defined by the following selection codes:

-1: 1/2" (15 mm) to 1-1/2" (40 mm) pipe sizes
-2: 2" (50 mm) to 10" (250 mm) pipe sizes
-C: 1/2" female NPT with PVC cable for conduit connection
-B: Cable gland with burial rated cable
-P: Cable gland with PVC jacketed cable
Cable Length Codes (-03 to -50): Specify lengths from 3 ft (0.91 m) up to 50 ft (15.24 m)
-BSPT: Adds a 1/2" BSPT process connection option