Cleveland Controls
Division of UniControl Inc
.
(Figure 1)
APPLICATION
The
Model AFS-460–137
is a general pur-
pose airflow 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 specified
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
firm-wall sample lines of ¼" OD tubing by
means of ferrule and nut compression con
-
nections. An optional ¼" adapter, suitable
for slip-on flexible 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 five 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
