Dwyer BYDS - Manual

DWYER INSTRUMENTS, INC.
Phone: 219/879-8000 www.dwyer-inst.com
P.O. Box 373 • Michigan City, IN 46360, U.S.A. Fax: 219/872-9057 e-mail: [email protected]
The Series BYDS Bypass Damper Switch is designed to control motorized
bypass dampers. As individual zone dampers open and close, the system static
pressure will rise and fall. In order to maintain proper airflow and static pressure
through the HVAC system, a bypass system incorporating a floating type motorized
damper and a static pressure control should be incorporated. A typical on/off
pressure switch cannot operate in this application due to the high cycle rate that
would result, eventually causing contact burn-out. The BYDS static pressure
control is equipped with a solid-state switching and timing circuit to enhance
operation and improve long-term reliability in this demanding application.
CONTROL OPERATION
The BYDS Bypass Damper Switch is designed for use with a three wire floating
point damper actuator used to control the static pressure on zone control systems
requiring motorized bypass dampers. A bypass damper, bypasses air from the
discharge air side of the HVAC unit back in the return air side. The air flow is
modulated in order to maintain a constant static pressure in the system as
individual zone dampers open and close. The static pressure control is equipped
with solid-state switching which dramatically increases the life of the control. On an
increase in static pressure the BYDS will send 24 volts out on terminal three (3)
and start the actuator to drive open. (See Terminal Designations Diagram). When
the static pressure reaches set-point the actuator will stop. After a ten second delay
the actuator will start to drive the damper closed if there has not been an increase
in static pressure. A green LED indicates when the damper is in the open position
or being driven open. A 24 VAC transformer is required to power the BYDS control
and damper actuator. Wiring is made directly to terminals located behind the
removable front cover. The unit includes tubing and two static pressure probes.
Series BYDS Bypass Damper Switch
Specifications - Installation and Operating Instructions
Bulletin P-BYDS
SPECIFICATIONS
Service: Air and non-combustible, compatible gases.
Materials:
Diaphragm material: Silicone;
Housing material: Switch body: PA 6.6 and POM;
Cover: Polystyrene.
Temperature Limits: Process ambient temperature from 32 to 122°F (0 to 50°C).
Pressure Limits: Max. operating pressure: 40 in w.c. (10 kPa) for all pressure
ranges.
Switch Type: Single-pole double-throw (SPDT).
Electrical Rating: 1A @ 24 VAC.
Electrical Connections: Screw terminal block. M20 x 1.5 with cable strain relief
or 1/2˝ NPT connection.
Process Connections: 5/16˝ (7.94 mm) outside diameter tubing, 1/4˝ (6.0 mm)
inside diameter tubing.
Mounting Orientation: Vertically, with pressure connections pointing downwards.
Mechanical Working Life: Over 10
6 switching operations.
Weight: 5.6 oz (160 g).
Enclosure Rating: NEMA 13, IP54.
Agency Approvals: CE, RoHS.
21/64
[8.5]
ш11/64
[ш4.5]
2-17/64
[57.5]
ш15/64
[ш6]
2-9/16 [65]
1-31/32 [50]
2-21/64
[59]
7/8
[22]
19/64
[7.5]
+
(P1)
-
(P2)
51/64
[18]
ADJUSTMENT KNOB
LOCATION
REMOVABLE CONNECTOR
1/2 NPT OR M20 x 1.50
ADJUSTMENT KNOB
SCALE 2:1