Model AFS-953 in Standard NEMA-1 rated housing:
• Coated steel finish.
• Shipping Weight:
5 lbs.
Figure 2:
“Shelf” Condition: AFS-953 contacts
before pressure amd power are applied.
MODEL AFS-953 AIR PRESSURE SENSING SWITCH
Mounting Position:
Mount with the diaphragm in any
vertical plane.
Set Point Range:
0.05 ± 0.02" w.c. to 12.0"w.c. (1.3 to
305 mm wc; 0 to 0.43 psi).
Field Adjustable
“Operate Range”:
0.07"w.c. to 12.0"
w.c.
Field Adjustable
“Release Range”:
0.04"w.c. to 11.2"
w.c.
Approximate Switching Differential:
Progressive,
increasing from 0.02± 0.01"w.c. at minimum set point to
approximately 0.8" w.c. at maximum set point. (0.5 ±
.25 mm to approximately 20.3 mm).
Operating Temperature Range:
0F to 130F (-18 to
54.4C).
Measured Media:
Air or combustion by-products that
will not degrade silicone.
Maximum Pressure:
½ psi (0.03 bar).
Life:
100,000 cycles minimum at 1/2 psi maximum
pressure each cycle and at maximum rated electrical
load.
Electrical Rating–Relay Switching Capacity:
3 amps at 115 V AC at 50/60 Hz.
Power consumption: 4.5 watts at 120 vAC.
Contact Arrangement:
SPDT NC (single pole, double-
throw snap action switch; contacts are in normally
closed position before pressure is applied to the
diaphragm.)
Electrical Connections:
5 numbered terminals, pressure
clamp screw type.
Conduit Opening:
7/8" diameter opening accepts 1/2"
conduit.
Sample Line Connectors:
Two ¼"—18 NPT female
fittings.
Approval:
FM approved.
Shipping Weight:
AFS - 953 (std. enclosure):
5 lbs.
AFS - 953 - 1 NEMA 4 enclosure:
8 lbs.
AFS - 953 - 2 NEMA 7/9 enclosure:
18 lbs.
Figure 1: Sample Line Connections
L
H
H
L
H: L:
HIGH POSITIVE LOW POSITIVE
POSITIVE NEGATIVE
LOW NEGATIVE HIGH NEGATIVE
CLEVELAND CONTROLS
DIVISION OF UNICONTROL INC.
MODEL AFS-953-B
Remove Plug Button to Adjust
Turn Clockwise to Increase
Operating Set Point.
TD -1
TD - 2
Red
Signal
Lamp
Enclosure
Cover
Low Pressure Inlet
¼ NPT
High Pressure Inlet
¼ NPT
0.281” (7 mm)
mounting holes (4)
AFS-953
.875" hole
accepts
½" conduit
Plug Button
to access
adjusting
screw
1.75"
(44 mm)
4.38"
(111 mm)
3.59"
(91 mm)
5.88"
(149 mm)
5.25"
(133 mm)
1.00"
(25 mm)
6.00"
(152 mm)
2.31"
(59 mm)
1.25"
(32 mm)
8.00"
(203 mm)
3.56"
(90 mm)
1.44"
(37 mm)
R
2
1
TD-1
TD - 1
(20 SEC)
TDA-20-0
C
NC
NO
LOW
PRESSURE
HIGH
PRESSURE
115 V AC
T
T
TD - 2
(8 SEC)
TDA-8-0
PREPURGE BYPASS.
INSTALL JUMPER HERE
ONLY IF SUFFICIENT
PREPURGE PERIOD IS
ALREADY PROVIDED
WITH THE BURNER
CONTROLS.
3
TO DELAYED LOW VOLTAGE
CIRCUIT OR LINE VOLTAGE
CIRCUITS. TOTAL CONNECTED
LOAD NOT TO EXCEED 2 AMPS
RESISTIVE, OR 62.5 VA PILOT
DUTY (INDUCTIVE).
TD-2
