UNICONTROL Electronic Cleveland Controls AFS-460-137 User manual

Cleveland Controls
Division of UniControl Inc.
(Figure 1)
APPLICATION
The Model AFS-460–137 is a general pur-
pose airow proving switch designed for 24
VAC HVAC and Energy Management ap-
plications where a manual reset switch with
DPDT contacts is desirable. It may be used
to sense positive, negative, or differential
air pressure.
GENERAL DESCRIPTION &
OPERATION
The plated housing contains a diaphragm, a
calibration spring, a snap-acting switch with
manual reset button, and a dpdt relay.
The sample connections located on each
side of the diaphragm accept .25" OD tub-
ing via the integral compression ferrule and
nut.
An enclosure cover guards against acci-
dental contact with the live switch terminal
screws and the set point adjusting screw.
The enclosure cover will accept a 0.5" con-
duit connection. The manual reset button is
located on the top surface of the enclosure
cover.
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 lowest specied
operating set point. Avoid mounting with the
(Figure 2)
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-460–137 is designed to accept
rm-wall sample lines of ¼" OD tubing by
means of ferrule and nut compression con-
nections. An optional ¼" adapter, suitable
for slip-on exible tubing is available. 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 mini-
mum of 1.5 duct diameters downstream from
the air source. Install the sampling probe as
close to the center of the airstream as pos-
sible. Refer to Figure 2 to identify the high
pressure inlet (H), and the low pressure inlet
(L). Select one of the ve application options
listed below, 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 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.
Model
AFS–460–137
Manual Reset DPDT Air Pressure Sensing Switch for 24 VAC Applications

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 by-products that
will not degrade silicone.
Mounting Position (in order
to meet lowest operating
specications): Diaphragm in any
vertical plane.
Field Adjustable Range:
0.40 ± .06"w.c. to 12.0"w.c.
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 amps @ 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
ELECTRICAL CONNECTIONS
(SEE FIGURE 3)
Before pressure is applied to the diaphragm,
the snap switch contacts will be in the nor-
mally closed (NC) position. As differential
pressure rises above the eld 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 reset
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 counterclockwise
until motion has stopped. Next, turn the ad-
justing 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 1.16" w.c.
Please note: To properly calibrate an Air
Switch, a digital manometer or other mea-
suring device should be used to conrm the
actual set point.
(Figure 3) Shown in "on shelf" condition:
no power and no differential pressure
applied.