Product Overview
Flow Switches, Paddle /
Flow Switches, Thermal
FLOW
THERMAL DISPERSION FLOW SWITCH
Non-Mechanical, Low Pressure Drop
SERIES TDFS2 | W.E. ANDERSON
™
BY DWYER
VANE FLOW SWITCH
Low Cost, Field Adjustable Set Point and Paddle
The Series FS-2 Vane Flow Switch offers an economical ow proving solution. The
FS-2 paddles are adjustable to t 1 to 8˝ size pipe.
FEATURES/BENEFITS
• Field adjustable set point adjustment screw allows for easy ow switch modication
• Custom application set points enabled by eld adjustable vane layers
• Aluminum weatherproof housing permits outdoor installation
APPLICATIONS
• Boiler ow proving
• Hot water heaters
• Chillers
• Cooling lines
• Machinery
• Liquid transfer systems
5-1/8 [130.2]
5-49/64
[146.5]
5 [127]
4-17/64
[108.3]
2-13/32
[61.1]
3-1/32
[77]
x
SPECIFICATIONS
Service: Compatible liquids.
Wetted Materials: Bellow: Tin-bronze;
Vane: SS; Body: Forged brass.
Temperature Limit: 230°F (110°C).
Pressure Limit: 145 psig (10 bar).
Enclosure Rating: NEMA 4 (IP64).
Switch Type: SPDT snap switch.
Electrical Rating: 10 A res, 3 A ind @
250 VAC.
Electrical Connection: Cable gland with
attached wire leads or optional conduit
connection.
Process Connection: 1˝ male NPT or
BSPT.
Mounting Orientation: Switch must
be installed vertically on horizontal pipe
runs.
Set Point Adjustment: Four vane
combinations and an adjustment screw.
Enclosure: Die-cast aluminum alloy.
Weight: 28.22 oz (0.8 kg).
Agency Approvals: CE.
SPECIFICATIONS
Service: Compatible water-based uids.
Wetted Materials: 316 SS.
Setpoint Range: 0.5 to 10 ft/s (0.15 to 3.0 m/s).
Repeatability: 0.07 ft/s +3% of setpoint.
Typical Deadband: 0.1 ft/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.
Switching Current: 400 mA, derate 5 mA/°C above 23°C.
Current Consumption: Average: 93 mA, Peak: 300 mA.
Electrical Connection: 1/2˝ NPT cable gland with 4 conductor 22 AWG, 6´ (1.83
m) cable.
Process Connection: 1/2˝ NPT male.
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.
Shown with conduit connection option
SERIES FS-2 | W. E. ANDERSON
™
BY DWYER
®
OPTIONS
To order add sufx: Description
-BSPT Process connection
Example: FS-2-BSPT
-CND Conduit connection, 1˝ NPT female conduit connection with
no wire leads.
Example: FS-2-CND
APPROXIMATE ACTUATION/DEACTUATION FLOW RATES FOR WATER;
GPM (LPM)
Pipe
Size
Blade Vane
Length in
(mm) Dim. X
Minimum Setting Maximum Setting
Actuate Deactuate Actuate Deactuate
1˝
1-1/4˝
1-1/2˝
2˝
2-1/2˝
3˝
4˝
5˝
6˝
8˝
1.34 (34)
1.34 (34)
2.24 (57)
2.24 (57)
3.46 (88)
3.46 (88)
3.46 (88)
6.57 (167)
6.57 (167)
6.57 (167)
4.0 (15.0)
5.3 (20.0)
7.0 (26.7)
14.1 (53.3)
18.5 (70.0)
27.7 (105.0)
59.4 (225.0)
52.8 (200.0)
75.7 (286.7)
184.9 (700.0)
1.8 (6.7)
2.6 (10.0)
4.0 (15.0)
9.7 (36.7)
15.4 (58.3)
25.1 (95.0)
52.8 (200.0)
39.6 (150.0)
52.8 (200.0)
158.5 (600.0)
8.8 (33.3)
11.4 (43.3)
14.5 (55.0)
31.3 (118.3)
35.2 (133.3)
52.8 (200.0)
123.3 (466.7)
132.1 (500.0)
154.1 (583.3)
396.3 (1500.0)
6.6 (25.0)
8.4 (31.7)
11.4 (43.3)
22.5 (85.0)
30.8 (116.7)
46.2 (175.0)
114.5 (433.3)
123.3 (466.7)
140.9 (533.3)
374.2 (1416.7)
USA: California Proposition 65
WARNING: Cancer and Reproductive Harm - www.P65Warnings.ca.gov
4-3/16
[106.17]
1-21/64
[33.78]
1-1/8
HEX
SENSOR
PROCESS CONNECTION
1/2˝ NPT
SETPOINT TARGET
STATUS INDICATOR
CABLE GLAND
CABLE
29/64 [11.68]
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 eld adjustable 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
• Set point is easily eld set by tapping the included magnet on the set point target
three times at the desired ow rate
• LED status indicators provide visual switch indication of ow rate in comparison to
the set point
• 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
V
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DWYER INSTRUMENTS, INC. | dwyer-inst.com276
MODEL CHART
Model Description
FS-2 Paddle ow switch
MODEL CHART
Model Description
TDFS2-1-P-06 Thermal ow switch, 6´ (1.83 m)
cable with cable gland
Note: Consult factory for longer cable lengths.
Flow_2021.indb 276 7/15/20 12:03 PM