Dwyer AAFS User Manual
Model AAFS Adjustable Air Flow Switch
ADJUSTMENT
SCREW
G
ROUND
S
HIELDED
T
ERMINAL
B
LOCK
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]
Ø
0.20
[
Ø5.00]
ADJUSTMENT
SCREW
GROUND
SHIELDED
TERMINAL
BLOCK
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 field adjustable from 200 to
1800 FPM (1 to 9.2 m/sec).
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 flow. Attach switch to duct with
sheet metal screws.
4. To make electrical connections, loosen the retaining screws and
remove the conduit enclosure cover. The SPDT snap switch has screw
terminals marked common, normally open and normally closed. A
ground screw is also provided. On increasing flow, the normally open
contacts will close and the normally closed contacts will open as the set
point is passed. See figure 1 for details.
5. To adjust set point, turn the flat-head screw located under the
enclosure cover. Rotate clockwise to increase setting or counterclockwise to decrease.
6. After all electrical connections and adjustments are complete, replace
conduit enclosure cover.
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 flow.
Set Point: Internal screw.
Enclosure Rating: IP65.
Weight: 13.6 oz (380 g).
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.
©Copyright 2012 Dwyer Instruments, Inc. Printed in U.S.A. 10/12 FR# R1-444037-00 Rev.1
DWYER INSTRUMENTS, INC.
P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: 219/872-9057 e-mail: info@dwyer-inst.com
Figure 1
Phone: 219/879-8000 www.dwyer-inst.com
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