Product Overview

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

Bulletin AFS 275.00

Air Pressure Sensing Switch with Adjustable Set Point Range

Dimensions in Inches

(Millimeters)

APPLICATION

Model AFS–275 is a general purpose

proving switch designed for HVAC

and Energy Management applications.

It may be used to sense positive, nega-

tive, or differential air pressure.

GENERAL DESCRIPTION

& OPERATION

The plated housing contains a dia-

phragm, a calibration spring, and a

snap-acting SPDT switch. The sample

line connections located on each side

of the diaphragm accept flexible tub-

ing. The electrical connection consists

of male ¼-inch quick connect termi-

nals.

MOUNTING

(SEE FIGURE 1)

Select a mounting location which is

free from vibration. The AFS–275 must

be mounted with the diaphragm in any

vertical plane in order to maintain the

specified operating set point. Avoid

mounting with the sample line connec-

tions 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 is equipped with two

slip-on sample line connections, situ-

ated on either side of the diaphragm

as shown in Figure 2. These connec-

tions are suitable for flexible tubing.

Locate the sampling probe a minimum

of 1.5 duct diameters downstream from

the air source. For sample lines up to

10 feet in length, ¼"OD tubing is ac-

ceptable. 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 center of the air

stream as possible.

Model

AFS–275

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 Air Pressure Sensing Switch with Adjustable Set Point Range APPLICATION Model AFS–275 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 line connections located on each side of the diaphragm accept flexible tubing.
PAGE 2
Figure 4 SPECIFICATIONS ELECTRICAL CONNECTIONS (FIGURES 3 & 4) 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. 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.