Product Overview

SPECIFICATIONS
MODEL AFS-228 AIR PRESSURE
SENSING SWITCH WITH
ADJUSTABLE SET POINT RANGE
Mounting Position:
Mount with the diaphragm in any vertical
plane.
Set Point Range:
0.05 ± 0.02" w.c. to 12.0"w.c.
Field Adjustable “Operate Range”:
0.07"w.c. to 12.0" w.c.
Field Adjustable “Release Range”:
0.04"w.c. to 11.2" w.c.
Approximate Switching Differential:
Progressive, increasing from 0.02 ±
0.01"w.c. at minimum set point to ap-
proximately 0.8 " w.c. at maximum set
point.
Measured Media:
Air, or combustion by-products that will
not degrade silicone.
Maximum Pressure:
½ psi (0.03 bar).
Operating Temperature Range:
-40F to 180F (-40 to 82C).
Life:
100,000 cycles minimum at ½ psi
maximum pressure each cycle and at
maximum rated electrical load.
Electrical Rating:
300 VA pilot duty at 115 to 277 VAC,
15 amps noninductive to 277 VAC,
60Hz.
Contact Arrangement: SPDT.
Electrical Connections:
¼" 90°quick connect spade terminals.
Conduit Opening:
⅞" diameter opening accepts ½"
conduit.
Sample Line Connectors:
Male, externally threaded
7
⁄16" -24 UNS
2A thread, complete with nuts and self-
aligning ferrules.
Sample Line Connections:
Connectors will accept ¼" OD rigid or
semi-rigid tubing.
Approvals: UL, FM, CSA.
Shipping Weight: 1.2 lbs.
Accessories:
• P/N 18311 Slip-on ¼" OD Tubing Adapter,
suitable for slipping on fl exible plastic
tubing.
• Sample line probes.
• Orifi ce plugs (pulsation dampers).
Nominal Dimensions in Inches
(
Millimeters
)
ELECTRICAL CONNECTIONS
(
SEE FIGURE 3
)
Before pressure is applied to the diaphragm,
the switch contacts will be in the normally
closed (NC) position. The snap switch has
¼" 90° quick connect spade terminals. Wire
alarm and control applications as shown in
Figure 4.
FIELD ADJUSTMENT
The adjustment range of an AFS-228 Air
Switch is 0.05 ±.02" w.c. to 12.0" w.c. To
adjust the set point, t urn the adjusting screw
counterclockwise until motion has stopped.
Next, turn the adjusting screw 4 complete
turns in a clockwise direction to engage
the spring. From this point, the next ten
turns will be used for the actual calibration.
Each full turn represents approximately
1.2" w.c.
Please note: To properly calibrate an air
switch, a digital manometer or other mea-
suring device should be used to confi rm the
actual set point.
(
Figure 4
)
(
Figure 3
)
(
Figure 2
)