Product Overview

ManualsBrandsCleveland Controls ManualsAir Pressure SwitchesSPDT Air Pressure Proving Switch (.05" - 2.0" W.C.)

Bulletin AFS 275112.01

Air Pressure Sensing Switch with Adjustable Set Point Range

Dimensions in Inches

(Millimeters)

APPLICATION

Model AFS–275–112 is a general pur-

pose proving switch designed for

HVAC and Energy Management ap-

plications. It may be used to sense

positive, negative, or differential air

pressure.

GENERAL DESCRIPTION

& OPERATION

The plated housing contains a dia-

phragm, a calibration spring, and a

snap-acting SPDT switch. The barbed

sample line connections located on

each side of the diaphragm accept flex-

ible tubing. The electrical connection

consists of male ¼-inch quick connect

terminals.

MOUNTING

(SEE FIGURE 1)

Select a mounting location which is

free from vibration. The AFS–275–112

must be mounted with the diaphragm

in any vertical plane in order to main-

tain the specified operating set point.

Avoid mounting with the sample line

connections in the "up" position.

Surface mount via the two

/16" diam-

eter holes on the zinc-plated strap

bracket.The mounting holes are 3-

/8"

apart.

AIR SAMPLING

CONNECTION

(FIGURE 2)

The AFS–275–112 is equipped with

two barbed, slip-on sample line con-

nections, situated on either side of the

diaphragm as shown in Figure 2.

These connections are suitable for flex-

ible tubing. Locate the sampling probe

a minimum of 1.5 duct diameters down-

stream from the air source. For sample

lines up to 10 feet in length, 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. Install

the sampling probe as close to the cen-

ter of the air stream as possible.

Model

AFS–275–112

Figure 2

Figure 1: Mount with the

diaphragm in any vertical plane.

Figure 3

Positive Only

Lower Negative

Higher Positive

Negative Only

Higher Negative

Lower Positive

Summary of content (2 pages)

PAGE 1
Model AFS–275–112 Air Pressure Sensing Switch with Adjustable Set Point Range APPLICATION Model AFS–275–112 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 barbed sample line connections located on each side of the diaphragm accept flexible tubing.
PAGE 2
Figure 4 ELECTRICAL CONNECTIONS (FIGURES 3 & 4) SPECIFICATIONS Before pressure is applied to the diaphragm, the switch contacts will be in the normally closed (NC) position. The snap switch has 90º male quick connect terminals. Wire control and alarm functions as shown in Figure 4. FIELD ADJUSTMENT 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.