Model AAFS Adjustable Air Flow Switch
Specications - Installation and Operating Instructions
Bulletin AQ-AAFS
The Model AAFS Adjustable Air Flow Switch is capable of detecting a wide range of
air velocities with minimal user calibration. The adjustable screw changes the set point
at which the SPDT snap switch engages. Quality features include a stainless steel
vane, galvanized steel base, and ABS enclosure. The unit is eld adjustable from 200
to 1800 FPM (1 to 9.2 m/s).
INSTALLATION
1. Select a location in a horizontal duct at least 10 duct diameters from fans and 7
diameters from elbows, size changes, etc. which can cause turbulence. Also, avoid
areas with excess vibration or where the temperature limits might be exceeded.
Switch can be mounted in any horizontal duct.
2. Use vane as received for 8˝ (203 mm) or larger ducts. Trim for smaller ducts.
3. Cut a mounting hole and slot for the vane and drill four 3/32˝ (2.38 mm) screw
holes. Insert switch through slot and rotate so arrow on switch enclosure points in
direction of air ow. Attach switch to duct with sheet metal screws.
4. To make electrical connections, loosen the retaining screws and remove the
conduit enclosure cover. See Figure 2. The SPDT snap switch has screw terminals
marked common, normally open and normally closed. A ground screw is also
provided. On decreasing ow, the normally open contacts will close and the
normally closed contacts will open as the set point is passed. See Figure 1.
5. To adjust set point, turn the at-head screw located under the enclosure cover.
Rotate clockwise to increase setting or counter-clockwise to decrease. See Figure
2.
6. After all electrical connections and adjustments are complete, replace conduit
enclosure cover.
MAINTENANCE/REPAIR
The only adjustment is that of the set point. Care should be taken to keep switch dry
and free of dust, dirt and oil. No lubrication or routine maintenance is necessary in
normal service.
WARRANTY/RETURN
Refer to “Terms and Conditions of Sales” in our catalog and on our website. Contact
customer service to receive a Return Goods Authorization number before shipping the
product back for repair. Be sure to include a brief description of the problem plus any
additional application notes.
Figure 1
Figure 2
SPECIFICATIONS
Service: Air and compatible gas.
Wetted Materials: Vane: SS; Lever: Brass; Base: Galvanized steel.
Housing: ABS.
Temperature Limits: Ambient: -40 to 180°F (-40 to 85°C); Process: -14 to 185°F
(-10 to 85°C).
Humidity Limits: 10 to 90%, non-condensing.
Switch Type: SPDT.
Electrical Rating: 15(8) A @ 250 VAC.
Electrical Connection: Screw terminal with M18 x 1.5 cable gland.
Process Connection: Flange.
Mounting Orientation: Horizontal duct ow.
Set Point: Internal screw.
Enclosure Rating: IP65.
Weight: 13.6 oz (380 g).
Agency Approvals: CE
ADJUSTMENT
SCREW
GROUND
SHIELDED
TERMINAL
BLOCK
5.94
[151.00]
2.81
[71.50]
M18X1.5
PROCESS
CONNECTION
3.86
[98.00]
4.92
[125.00]
3.15
[80.00]
1.02
[26.00]
4.15
[105.50]
2.56
[65.00]
2.81
[71.50]
0.49
[12.50]
6.89
[175.00]
3.86
[98.00]
3.03
[77.00]
4.02
[102.00]
3.46
[88.00]
2.56
[65.00]
2.52
[64.00]
Ø0.20
[Ø5.00]
1
2
3
1
2
3
+
-
NCNOCOM
231
ADJUSTMENT SCREW
GROUND
SHIELDED
TERMINAL BLOCK
Switch position when air ow is
present: continuity between terminal
1 and 2
Switch position when no-air ow is
present: continuity between terminal
1 and 3
Printed in U.S.A. 7/18 FR# 444037-00 Rev. 3©Copyright 2018 Dwyer Instruments, Inc.
®
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A.
Phone: 219/879-8000
Fax: 219/872-9057
www.dwyer-inst.com
e-mail: [email protected]
/