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Cleveland Controls
Model
Division of UniControl Inc.
AFS–460
ADJUSTABLE SET POINT AIR PRESSURE SENSING SWITCH WITH MANUAL RESET
APPLICATION
The Model AFS-460 is a general purpose
proving switch designed to require
manual operator reset following actuation.
It can be used to sense positive, negative, or differential air pressure in HVAC
and Energy Management applications
which require operator interface.
General Description & Operation
The plated housing contains a diaphragm,
a calibration spring and a snap-acting
SPST–NC switch with manual reset button.
The sample connections located on each
side of the diaphragm accept 0.25" OD
metallic tubing via the integral compression ferrule and nut.
An enclosure cover protects the operator
from accidental contact with the live
switch terminal screws and the set point
adjusting screw. The enclosure cover accepts a 0.5" conduit connection.
MOUNTING (SEE FIGURE 1)
Select a mounting location which is free
from vibration. The AFS-460 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.
(Figure 1)
AIR SAMPLING CONNECTION
(SEE FIGURE 2)
The AFS-460 is designed to accept firmwall sample lines of ¼" OD tubing by
means of ferrule and nut compression
connections. An optional ¼" adapter , suitable for slip-on flexible tubing is available:
order part number 18311. 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.
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 five application options listed on page 2, and connect the sample lines as recommended.
POSITIVE PRESSURE ONLY: Connect
the sample line to inlet H; inlet L remains
open to the atmosphere.
NEGA TIVE PRESSURE ONLY: Connect
the sample line to inlet L; 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 NEGATIVE
SAMPLE: Connect the positive sample
to inlet H. Connect the negative sample
to inlet L.
Cleveland Controls
DIV
Bulletin AFS460.06
ISION OF UNICONTROL INC.
Page 2
(Figure 2)
(Figure 3)
(Figure 4)
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-460
Air Switch is 0.4" ± 0.02" 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 four 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 1.16" 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-460 AIR
PRESSURE SENSING
SWITCH WITH MANUAL
RESET FEATURE
Mounting Position (in order to meet
lowest operating specifications): Mount
with the diaphragm in any vertical plane.
Set Point Range:
0.40 ± 0.06"w.c. to 12.0"w.c.
Field Adjustable “Operate Range”:
0.46"w.c. to 12.0" w.c.
Field Adjustable “Release Range”:
0.46"w.c. to 11.2" w.c.
Approximate Switch Differential:
Progressive, increasing from approximately
0.06± 0.01"w.c. at minimum set point, to
approximately 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)
Life: Exceeds UL-recognized mechani-
cal endurance test of 6,000 cycles
minimum at 0.5 psi maximum pressure
each cycle and at maximum electrical
load.
Electrical Rating: @ 60 Hz.
15 amp 125, 250, or 277 VAC
¼ hp 125 V AC, ½Hp 250 VAC,
½ amp 125 V DC,
¼ amp 250 V DC .
Contact Arrangement:
SPST–NC (manual reset).
Electrical Connections:
Screw top 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 selfaligning ferrules.
Sample Line Connections: Connectors will accept ¼" OD rigid or semi-rigid
tubing.
Approval and Recognition:
UL, CSA, CE.
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).
Nominal Dimensions in Inches (Millimeters)
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