Cleveland Controls AFS-460-137 User manual

Bulletin AFS 460137.03
Cleveland Controls
Division of UniControl Inc.
111Brookpark Road • Cleveland OH 44109
TEL: [phone] • FAX: [phone]
Distributed by:
(Figure 1)
Application
The Model AFS-460–137 is a general
purpose airflow proving switch designed
for 24 VAC HVAC and Energy Manage-
ment applications where a manual reset
switch with DPDT contacts is desirable.
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, a snap-act-
ing switch with manual reset button, and
a dpdt relay.
The sample connections located on each
side of the diaphragm accept .25" OD
tubing via the integral compression fer-
rule and nut.
An enclosure cover guards against ac-
cidental contact with the live switch ter-
minal screws and the set point adjusting
screw. The enclosure cover will accept
a 0.5" conduit connection. The manual
reset button is located on the top sur-
face of the enclosure cover.
(Figure 2)
Mounting (see Figure 1)
Select a mounting location which is free
from vibration. The AFS-460–137 must
be mounted with the diaphragm in any
vertical plane in order to obtain the low-
est specified operating set point. Avoid
mounting with the sample line connec-
tions in the "up" position. Surface mount
via the two 3/16" diameter holes in the
integral mounting bracket. The mount-
ing holes are 3-7/8" apart.
Air Sampling Connection
(see Figure 2)
The AFS-460–137 is designed to accept
firm-wall sample lines of ¼" OD tubing
by means of ferrule and nut compres-
sion connections. An optional ¼"
adapter, suitable for slip-on flexible tub-
ing is available. For sample lines of up
to 10 feet, ¼" OD tubing is acceptable.
For lines up to 20 feet, use ¼" ID tub-
ing. For lines up to 60 feet, use ½" ID
tubing. Locate the sampling probe a
minimum of 1.5 duct diameters down-
stream 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 op-
tions listed below, and connect the
sample lines as recommended.
Model
AFS–460–137
Manual Reset DPDT Air Pressure Sensing Switch for 24 VAC Applications

Bulletin AFS 460137.03 2
Specifications
Model AFS–460–137 Air
Pressure Sensing Switch with
manual reset feature, DPDT
contact arrangement , for 24 VAC
applications.
Sample Media: Air or
combustion products that do not
degrade silicone.
Mounting Position (in order to
meet lowest operating
specifications): Diaphragm in any
vertical plane.
Field Adjustable Range:
0.40 ± .06"w.c. to 12.0"w.c.
Switch Differential: Progressive,
increasing from approximately
.06± .01"w.c. at minimum set
point, to approximately .8"w.c. at
maximum set point.
Maximum Pressure:
0.5 psi (0.03 bar)
Operating Temperature Range:
-40 to 180F (-40 to 82C)
Electrical Rating:
0.5 VA @ 24 V AC, 50/60 Hz.
Contacts:
DPDT, 2 form-C
rated 8 amp @ 250 V AC.
Electrical Connections:
Screw terminals.
Sample Line Connections:
Ferrule and nut compression type
connectors will accept .25" OD
rigid tubing.
Shipping Weight: 1.2 lbs.
Agency Approvals: pending
Accessories
•P/N 18311 Slip-on ¼" OD Tubing Adapter,
suitable for slipping on flexible plastic
tubing. • Sample line probes. • Orifice
plugs (pulsation dampers).
Pressure Conversion Table
1" H2O = .0361 lbs./sq. in. or .0735 in. mercury
1" Hg. = .491 lbs./sq. in. or 13.6 in. water
1 psi = 27.7 in. water or 2.036 in. mercury
POSITIVE PRESSURE ONLY: Con-
nect the sample line to inlet H; inlet L
remains open to the atmosphere.
NEGATIVE PRESSURE ONLY: Con-
nect the sample line to inlet L; inlet H
remains open to the atmosphere.
TWO NEGATIVE SAMPLES: Con-
nect the higher negative sample to inlet
L. Connect the lower negative sample
to inlet H.
TWO POSITIVE SAMPLES: Con-
nect the higher positive sample to inlet
H. Connect the lower positive sample
to inlet L.
ONE POSITIVE AND ONE NEGA-
TIVE SAMPLE: 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 dia-
phragm, the snap switch contacts will be
in the normally closed (NC) position.
As differential pressure rises above the
field adjustable set point, the snap
switch opens, de-energizing the coil on
the slave relay, which activates the
DPDT contacts. An LED indicates that
the snap switch exceeds differential set
point. It remains lit until the manual re-
set push button is depressed.
Field Adjustment
The AFS-460–137 Manual Reset Air
Switch has an adjustment range of 0.40
to 12.0" w.c., ±.06" w.c. To adjust the
set point:
Turn the adjusting screw counterclock-
wise 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 cali-
bration. Each full turn represents ap-
proximately 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.
C
NC MANUAL
RESET
HIGH
PRESS
LOW
PRESS
H
K1
CONVERTER
NC1
NO 1 C1
NC2NO 2 C2
Shown in "on shelf " condition:
no power and no differential
pressure applied.
Note that when power is applied across
H and N :
1) Relay K1 is energized
2) Contacts change state (i.e., NO contact
closes and NC contact opens)
3) LED is illuminated when differential
pressure exceeds set point.
TB2 #1
24 V AC
TB2 #2
COMMON