Series BYDS Bypass Damper Switch

Bypass Damper Switch
Controls Zone Static by Modulating Motorized Damper

Controls Zone Static by Modulating Motorized Damper

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 burnout. 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 and start the actuator to drive open. 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. The unit includes tubing and two static pressure probes.

Product Applications

  • Air filter and ventilator monitoring
  • Industrial cooling circuits
  • Fire-protection damper control
  • Ventilation duct monitoring
  • Fan heater overheating protection
  • Heat exchanger frost protection
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 and ambient temperature from 32 to 122 °F (0 to 50 °C).
Pressure Limits: Max. Operating Pressure: 40" 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.
Enclosure Rating: NEMA 13 (IP54).
Mounting Orientation: Vertically, with pressure connections pointing downwards.
Mechanical Working Life: Over 106 switching operations.
Weight: 5.6 oz (160 g).
Agency Approvals: CE, RoHS.
  • Units include 2 plastic static pressure tips and 7 ft. (2.1 m) of PVC tubing.
  • Adjustment knob changes switching pressure easily with a pressure gage reducing components for application.
  • Low cost device makes it an excellent solution in BAS and HVAC applications requiring duct control and monitoring.
  • Relay contact allows simple integration with DDC or building systems.