designed for HVAC sensitive pressure switch

1.About us                                                                                                                                      

Keram(Nanjing) Controls & Equipments Co;,Ltd. Was founded in 2000,a professional manufacturer and supplier of controls equipment and products design. Our products are related to gas safety control,temperature control,time control,over-heating control, pressure and temperature controls used on refridgeration and compressor,water pressure switch and all kinds of solenoid valves and safety valves.

 New Building Of Keram Controls

keram control add more high precision CNC machine to improve product reliability and efficiency

2.Description                                                                                                                                  

The AFS are general purpose air flow proving switches designed for HVAC, detection of blocked filters and fan s flow monitoring in ducts, pipes, tunnels, and other energy management applications. It may be used to sensepositive, negative or differential air pressure.The plated housing contain a diaphragm, a calibration spring and a snap-acting switch. The sample connections locate on each side of the diaphragm accepting a 0.25" OD tubing via the integral compression 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 0.5" conduit connection. The AFS-460 has a reset button located on the top surface of the enclosure cover.

3.Specification                                                                                                                               

4.Dimensions in millimeters and(inches)                                                                                  

5.Installation                                                                                                                                   

MOUNTING (SEE FIGURE 1)

Select a mounting location which is free from vibration. The  AFS-222 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.

AIR SAMPLING CONNECTION (SEE FIGURE 2)

The AFS-222 is designed to accept firm wall sample lines of 1/4” OD tubing by means of ferrule and nut compression connection. For sample lines of up to 10 feet,1/4” OD tubing is acceptable. For lines up to 60 feet, use1/2” ID tubing. A 1/4” 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 as close 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 following five application options, and connect the sample lines as recommended.

POSITIVE PRESSURE ONLY: Connect the sample line to inlet H; Inlet L remains open to the atmosphere.
NEGATIVE PRESSURE ONLY: Connect the sample line to inlet H; Inlet H remains open to the atmosphere.
TWO NEGATIVE SAMPLES: Connect the 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 NEGATI: Connect the positive sample to inlet H. Connect the negative sample to inlet L.

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.

ALARM CONTROL(SEE FIGURE 4)

6. Field adjustment                                                                                                                        

The adjustment rang of an AFS-222 Air Switch is 0.05±.02 “w.c. to 12.0”w.c. To adjust the set point, turn 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 measuring device should be used to confirm the actual set point.

7. Product Process & Package