Schneider Electric AFS-262 Data Sheet

Cleveland Controls

Model

Division of UniControl Inc.

AFS–262

AIR PRESSURE SENSING SWITCH WITH ADJUSTABLE SET POINT RANGE

APPLICATION

Model AFS-262 Air Pressure Sensing Switch
is a general purpose proving switch de­signed for HVAC and Energy Management
applications. It may be used to sense posi­tive, negative, or differential air pressure.

GENERAL DESCRIPTION &
OPERATION

The plated housing contains a diaphragm, a
calibration spring and a snap-acting SPDT
switch.The sample connections located on
each side of the diaphragm accept ¼" OD
metallic tubing via the integral compression
ferrule and nut.

An enclosure cover guards against acci­dental contact with the live switch terminal
screws and the set point adjusting screw.
The enclosure cover will accept a ½" conduit
connection.

MOUNTING (SEE FIGURE 1)

Select a mounting location which is free from
vibration. The AFS-262 must be mounted
with the diaphragm in any vertical plane in
order to obtain the lowest specified operating
set point. Avoid mounting with the sample
line connections in the "up" position. Surface
mount via the two 3/16" diameter holes in
the integral mounting bracket. The mounting
holes are 3-7/8" apart.

The AFS-262 is designed to accept firm-wall
sample lines of ¼" OD tubing by means of
ferrule and nut compression connections.

(Figure 1)

AIR SAMPLING CONNECTION
(SEE FIGURE 2)

For sample lines of up to 10 feet, ¼" OD
tubing is acceptable. For lines up to 20 feet,
use ¼" ID tubing. For lines up to 60 feet, use
½" ID tubing. A ¼" OD adapter, suitable for
slip-on flexible tubing is available: order part
number 18311.

Locate the sampling probe a minimum of

1.5 duct diameters downstream from the air
source. Install the sampling probe
to the center of the airstream as possible.
Refer to Figure 2 to identify the high pres­sure inlet (H) and the low pressure inlet (L).
Select one of the five application options
listed below, and connect the sample lines
as recommended.

POSITIVE PRESSURE ONLY: Connect the
sample line to inlet H; inlet L remains open
to the atmosphere.

as close

NEGATIVE PRESSURE ONLY: Connect
the sample line to inlet L; inlet H remains
open to the atmosphere.

NEGATIVE SAMPLES: Connect the

TWO

higher negative sample to inlet L. Connect
the lower negative sample to inlet H.

TWO POSITIVE SAMPLES: Connect the
higher positive sample to inlet H. Connect
the lower positive sample to inlet L.

ONE POSITIVE AND ONE NEGATIVE
SAMPLE: Connect the positive sample

to inlet H. Connect the negative sample
to inlet L.

Bulletin AFS-262.06

Cleveland Controls

DIVISION OF UNICONTROL INC.

(Figure 2)

(Figure 3)

(Figure 4)

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
screw top terminals with cup washers. Wire
alarm and control applications as shown in
Figure 4.

FIELD ADJUSTMENT

The adjustment range of an AFS-262 Air
Switch is 0.05 ±.02" w.c. to 2.0" 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

0.2" w.c.

Please note: To properly calibrate an air

switch, a digital manometer or other mea­suring device should be used to confirm the
actual set point.

SPECIFICATIONS

MODEL AFS-262 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 2.0"w.c.

Field Adjustable “Operate Range”:

0.07"w.c. to 2.0" w.c.

Field Adjustable “Release Range”:

0.04"w.c. to 1.9" w.c.

Approximate Switching Differential:

Progressive, increasing from 0.02
± 0.01"w.c. at minimum set point to
approximately 0.1 " 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 1/2 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:

Screw-type terminals with cup
washers.

Conduit Opening:

7/8" 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 flexible
plastic tubing.

• Sample line probes.

• Orifice plugs (pulsation dampers).