Cleveland Controls
Division of UniControl Inc
.
Model
AFS–951
DESCRIPTION & OPERATION
The
Cleveland Controls AFS-951 Differ-
ential Pressure Sensing Switch
is designed
to provide precise operation and convenient
features for industrial and commercial air
handling applications. The
AFS-951
can
monitor positive, negative, or differential
pressure (flow) of air and noncombustible
gases. It is commonly used to monitor
combustion air, furnace pressure, ventilat
-
ing blower operation, inflatable structure
pressure, fume hood operation, bag house
air flow, dirt accumulation in air filters, and
heat-transfer air flow. The
AFS-951
has a
field–adjustable set point range of 0.05"wc
to 12.0"wc.
COMMON APPLICATIONS
The most common specific application for
the
AFS-951
is as a
Low Draft (Negative
Pressure) Cutoff Safety Switch
for com-
bustion draft control systems.
The general applications of the AFS-951
are:
• Low Positive Pressure Cutoff
. (Shut-
down upon insufficient pressure.)
• Low Negative Pressure Cutoff
. (Shut-
down upon insufficient draft.)
• Low Differential Pressure Cutoff
.
(Shutdown upon insufficient difference
between two samples.)
MOUNTING
The
AFS-951
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
specification, the control must be mounted
with the diaphragm vertical (Fig 1).
The standard enclosure has mounting flang
-
es 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-951-1 in NEMA-4 rated
Enclosure.
AFS-951 in St andard E nclosure,
rated NEMA-1.
AFS-951-2 in NEMA-7 and NEMA-9
rated Enclosure.
Adjustable Set Point Air Pressure Sensing Switch