Braeburn SPC User Manual
SPC (Static Pressure Controller)
• Air Pressure Sensing Switch
• For use with PO/PC Dampers
• Adjustable Air Switch Set Point Range
General Description
The SPC is a static pressure switch designed to sense positive pressure in
the plenum for the purpose of controlling modulating bypass position.
The plated housing contains a diaphragm, a calibration spring and a snapacting SPDT switch. The barbed sample line connections located on each
side of the diaphragm accept flexible tubing. The enclosure cover guards
against accidental contact with the live switch terminal and set point adjusting screws. The enclosure cover will accept a ½˝ conduit connection.
Pitot tube (air-probe) for mounting in plenum and 36 inches of flexible
¼ ˝ I.D. poly tubing is included with each SPC.
Initial Position Relay included to maintain open damper position during NO
FAN CALL (Not pictured).
Mounting
Select a mounting location which is free from vibration.
The SPC must be mounted with the diaphragm in any vertical plane in order to obtain the lowest specified operating
set point. Avoid mounting with the sample line connections
in the “up” position. Surface mounting by the two 3/16“
diameter holes in the integral mounting bracket. The
mounting holes are 3 7/8” apart as shown in Figure 3.
Air Sample Connection
The SPC is designed to accept a flexible tubing by means
of a barbed 1/4”slip-on connection. A 36” piece of ¼˝ ED
Flexible Tubing is included with the SPC as well as the
Pitot Tube for mounting in the plenum. Locate the sampling probe a minimum of 2 feet down stream from the air
source. Install the sampling probe as close to the center of
the airstream as possible. Do not allow supply pressure to
blow directly into the Pitot Tube. Connect the provided
flexible tubing to the High-Pressure Inlet as shown in
Figure 2.
Initial-Position Relay
Each SPC includes a SPDT Relay that should be wired in
conjunction with the SPC and Power-Open/Power-Close
Damper as shown in Figure 1. This relay is included so
that when there is NO CALL for the FAN on the equipment
side of the Braeburn Zone Controller the bypass damper
will drive open. When a FAN call occurs the relay allows
SPC to operate normally.
Br a ebu r n S y ste m s L LC, 22 1 5 C orn e ll Av e nue , M ontg ome r y, I lli n ois 6 0 538 , U .S. A .
Te l eph o ne (8 6 6) 268 -55 9 9, F acs i mil e ( 866) 2 6 8-3 6 11
Specifications
Mounting
Set Point 0.05 ± 0.02" w.c. to 2.0"w. c.
Range
Field Adj. 0.07”w.c. to 2 .0"w.c.
Operate Range
Field Adj. 0.04”w.c. to 1 .9"w.c.
Release Range
Field Adj. 0.07”w.c. to 2 .0"w.c.
Operate Range
Approx. Switching
Differential 0.02 ± 0.01”w.c. at minimum
set point.
Measured Media
Maximum Pressure ½ psi (0.03 b ar)
Operating -40ºF to 18 0ºF (-4 0ºC to 8 2ºC)
Temperature
Electrical 300VA pilot duty at 115 to
Rating 277 VAC, 15 Amps no n-inductive
277 VAC @ 60Hz
Contact SPDT
Arrangement
Sample Line ¼” B arbed connectors f or
Connections tubing
Approval UL, FM, CSA, CE
Mount with the diaphragm in any
vertical plane.
Progressive increasing from
set point to 0.1w.c. at maximum
Air or combustion by-products
that will not degrade silicone
. (See Figure 3)
1
3
4
2
5
Figure 1 – Wiring Diagram
Electrical Connections
Before pressure is applied to the diaphragm, the switch contacts on the SPC will be
in the normally closed (NC) position. This snap switch has screw top terminals with
cup washers. Wire according to Figure 1.
Modulating Bypass
Setup
With all zones calling (all dampers
open), make certain that the fan is
in the highest speed that will be
used when the sysem is running.
Turn the set screw clockwise ¼
turn each time until the bypass
damper motor is obviously running
closed. If the bypass damper
should reverse and start opening,
turn the set screw another ¼ turn
and repeat until the damper is
closed. Next, slowly turn the set
screw counter clockwise until the
bypass damper motor start to run
open. Immediately, turn the set
screw clockwise until the damper
motor starts to close again.
The goal is to set the bypass
damper so that it is barely staying
closed when all zones are open.
This will cause the bypass damper
to open if supply dampers close
and the plenum pressure goes up.
As dampers open and/or close
during operation, the static pressure sensor will sense a pressure
change and make the Power
Open/Power Close bypass
damper move to maintain the
same pressure in the plenum that
was established when all zone’s
were open.
Figure 2 – Dimensions
Br a ebu r n S y s te m s LL C , 2 215 Cor n ell Ave n ue, Mon t gom e ry, Ill i no i s 6 0 538 , U. S .A.
Te l eph o ne ( 866 ) 26 8 -5 5 99 , F acs i mile ( 866 ) 2 6 8- 36 1 1
Figure 3 – Mounting
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