Cleveland Controls
Division of UniControl Inc
.
Model
AFS–961
DESCRIPTION & OPERATION
The
Cleveland Controls AFS-961 Dif-
ferential Pressure Sensing Switch
is
designed to provide precise operation
and convenient features for industrial and
commercial air handling applications. The
AFS-961
can monitor positive, negative, or
differential pressure (flow) of air and non
-
combustible gases. It is commonly used to
monitor combustion air, furnace pressure,
ventilating blower operation, inflatable
structure pressure, fume hood operation,
bag house air flow, dirt accumulation in air
filters, and heat-transfer air flow. The
AFS-
961
has a field-adjustable set point range of
0.03"wc to 2.0"wc.
COMMON APPLICATIONS
The most common specific application for
the
AFS-961
is
Low Draft (Negative Pres-
sure) Cutoff Safety Switch
for combustion
draft control systems.
The general applications of the
AFS-961
are:
• Low Positive Pressure Cutoff
. (Shut-
down upon insufficient pressure.)
• Low Negative Pressure Cutoff
. (Shut-
down upon insufficient draft.)
• Low Differential Pressure Cutoff
. (Shut-
down upon insufficient difference between
two samples.)
MOUNTING
The
AFS-961
is available in 3 enclosures
designed for surface-mounting on any flat,
relatively stable surface free of vibration. To
obtain the lowest operating set point specifi
-
cation, the control must be mounted with the
diaphragm in a vertical plane(Fig 1).
The standard NEMA-1 rated enclosure has
mounting flanges with four
9
/
32
" mounting
holes as shown on page 4. The NEMA-4
rated model has mounting flanges with four
5
/
16
" mounting holes as shown on page 3.
The NEMA-7/NEMA-9 rated enclosure has
two mounting slots as shown on page 3.
AFS-961-1 in NEMA-4 rated Enclosure.
AFS-961 in Standard Enclosure, rated
NEMA-1.
AFS-961-2 in NEMA-7 and NEMA-9 rated
Enclosure.
Adjustable Set Point Air Pressure Sensing Switch
