Dwyer Instruments SERIES TDFS2 Catalog Page

SERIES TDFS2 | W.E. ANDERSON™ BY DWYER

5-1/8 [130.2]

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2-13/32

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[48.26]

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1-1/8
HEX

THERMAL DISPERSION FLOW SWITCH

Non-Mechanical, Low Pressure Drop, Large Pipe Sizes

Flow Switches, Thermal

Flow Switches, Paddle /

The Series TDFS2 Thermal Dispersion Flow Switch is a thermal ow switch

that indicates whether the ow rate is above or below a user set ow rate. The unit
incorporates two LED status indicators providing visual switch indication. The set ow
rate (setpoint) is easily eld adjustable with included magnet and the unit has both NO
and NC NPN outputs.

FEATURES/BENEFITS

• Better reliability and life expectancy than mechanical ow 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

• Not affected by empty pipe as it avoids overheating by actively heating above the
process temperature and then cooling down to process temperature

• Low pressure drop; only needs to be inserted 10% into the ow (e.g. 1/8˝ for 3/4˝
schedule 40 pipe)

APPLICATIONS

• Boiler ow proving

• Hot water heaters

• Chillers

• Liquid transfer systems

MODEL CHART

Example TDFS2 -1 -C -06 -BSPT TDFS2-1-C-06-BSPT
Series TDFS2 Thermal dispersion ow switch
Pipe Size 1

Electrical
Connection*

Cable Length X Cable length (ft.)
Options BSPT 1/2˝ BSPT process connection

*Per ft cable length adder.

DWYER INSTRUMENTS, INC. 276

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CABLE
CABLE GLAND

1-1/8

4-3/16

[106.17]

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TDFS2-1-P-06

TDFS2-2-P-06

1-21/64

[33.78]

TDFS2-1-P-06

29/64
[11.68]

STATUS INDICATOR
SETPOINT TARGET
PROCESS
CONNECTION 1/2˝ NPT

SENSOR

HEX

5-5/8

[142.88]

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[70.49]

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TDFS2-2-P-06

CABLE
CABLE GLAND

STATUS INDICATO
SETPOINT TARGET
PROCESS
CONNECTION
1/2˝ NPT OR BSPT

SENSOR

SPECIFICATIONS

2

Service: Compatible water-based uids.
Wetted Materials: 316 SS.
Pipe Range: 1/2 to 1-1/2˝ (15 to 40

mm) or 2 to 10˝ (50 to 250 mm) (model
selectable).
Setpoint 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.
Typical Deadband: 0.1 ft/s (0.03 m/s)
+15% of setpoint.
Temperature Limits: Ambient: 5 to
140°F (-15 to 60°C); Process: 5 to 140°F
(-15 to 60°C), Storage: -40 to 185°F (-40
to 85°C).

Pressure Limits: 300 psig (20.67 bar).
Response Time: Approximately 8 s.
Power Requirement: 9-24 VDC.

1/2 to 1-1/2˝ (15 to 40 mm) pipe sizes

C
B
P

2 to 10˝ (50 to 250 mm) pipe sizes
1/2˝ female NPT with PVC cable for conduit connection
Cable gland with burial rated cable
Cable gland with PVC jacketed cable

Switching Current: 400 mA, derate 5
mA/°C above 23°C.
Current Consumption: Average: 93
mA; Peak: 300 mA.
Electrical Connection: 1/2˝ NPT female
or cable gland with 4 conductor 22 AWG
6´ (1.83 m) long (model selectable).
Process Connection: 1/2˝ NPT or
BSPT male (model selectable).

Enclosure Rating: NEMA 4X (IP65).
Housing Materials: 316 SS, 416 SS,

polycarbonate, neoprene, and acrylated
urethane.

Switch Type: 1 NO NPN, 1 NC NPN.
Input Power and Protection: 0.5A fuse

(resettable) reverse polarity protected.
Switched Output Protection: 0.5A fuse
(resettable) reverse polarity protected.

Agency Approvals: CE.