Hazardous Rated Wall & Remote Mount NFPA 496 Building Pressurization Units

Standard Features

  • Bebco Model WDP and RDP Units include unique standard features which significantly enhance performance and ensure years of trouble-free service.
  • Compare these exceptional features with less sophisticated products to understand the value of what you receive from Bebco!
  • Bebco provides a comprehensive explanation of all standard features so you can easily evaluate the amazing value of our UL Classified Whisper Drive™ Building Pressurization Units!

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Unit Control Features

All Bebco Whisper Drive™ Wall and Remote Mount Building Pressurization Units feature a unique set of controls that ensure absolute compliance with all NFPA 496 Code requirements; while operating in a manner you prefer to establish critical parameters and preferred delays that ease entry and exit of your room or building and prevent unnecessary alarms.

These controls are located on the Variable Frequency Drive Interface (VFDI) Logic Control Board, and are provided in the form of two set point adjustments and two delay timer adjustments. All adjustment take affect in real time, as inputs to the on-board micro-processor, that is redundantly monitored by a watchdog timer and pulsing led, to supervise performance and display real-time operating status.

Bebco Model WDP and RDP Whisper Drive™ Pressurization Unit VFDI Logic Control Boards feature four adjustments critical to establishing code compliant operation and setting preferred parameters. The PFS control adjusts the primary fan speed in real time to maintain a safe pressure when all doors and other openings are sealed. In essence, the control overcomes all normal leakage, and ensures the unit will always hold a steady pressure. The ASP control adjusts the alarm activation setting, which must always be less than the safe pressure, to ensure proper operation.

The SFD sets a time delay that prevents the secondary fan from energizing immediately after loss of safe pressure. This delay is especially useful for rooms or buildings featuring vestibules, when the secondary fan may be counterproductive to allowing normal entry and exit. The ASD sets a time delay that prevents the alarm from activating immediately upon loss of safe pressure. This delay is useful to permit entry and exit without tripping false alarms, especially for rooms and building that are frequently accessed. For more information on these critical control features, please call a Bebco Sales Associate!

Unit Control Features
Field Adjustable Set Points & Delay Timers
Provides room pressure and alarm pressure settings, along with secondary fan and alarm activation timers.

Room Pressure & Alarm Activation Set points

  • PFS: Primary Fan Speed Set Point Adjustment
    sets primary fan speed to maintain safe room pressure.

    Factory Set Point: 0.25″
    Adjustment Range: 0.10″ to 0.40″

  • ASP: Alarm Activation Set Point Adjustment
    sets alarm to active upon loss of safe room pressure.

    Factory Set Point: 0.15″
    Adjustment Range: 0.05″ to 0.25″

Secondary Fan & Alarm Activation Delay Timers

  • SFD: Secondary Fan Activation Delay Adjustment
    sets time delay cycle to prohibit the secondary fan from engaging when room pressure falls below alarm set point.

    Factory Set Point: 0 Seconds
    Adjustment Range: 0-35 seconds

  • ASD: Alarm Signal Activation Delay Adjustment
    sets time delay cycle to prohibit alarm signal output when room pressure falls below alarm set point.

    Factory Set Point: 15 Seconds
    Adjustment Range: 0-35 seconds

    Delay Timers reset automatically if Safe Pressure is restored prior to expiration of the delay timer cycles.

Indicators & Operators

All Bebco Whisper Drive™ Wall and Remote Mount Building Pressurization Units are furnished with a 4″ diameter color-coded room pressure indicator, and an array of indicator lights and control operators to start, control and monitor the unit’s performance.

These devices are located above the discharge grille of Model WDP Units, and are provided with Model RDP Unit Remote Control Stations that are intended for mounting on an interior or exterior wall of your pressurized room or building.

As listed below, the room pressure indicator displays the positive differential pressure between your room or building and the surrounding external atmosphere, The indicators and control operators provide clear indication that the unit is running, allow you to engage the primary fan, and to disable or engage the secondary fan in manual or automatic modes. The controls also allow you to disable the alarm signal and provide clear
indication of whether the alarm is active or if it has been bypassed.

System Control Features
Field-Adjustable Set Points & Delay Timers

Provides room pressure and alarm pressure settings, along with secondary fan and alarm activation timers.

Room Pressure & Alarm Activation Set points

  • Room Pressure Indicator: 4” Color Coded Differential Pressure Gauge
                                             Indicates room pressure at range of 20 feet
  • Primary Fan On Indicator: Green Indicator Light
                                             Green Indicator Light illuminates when primary fan is engaged.
  • Primary Fan Control Switch: On/Off Selector Switch
                                             Engages and disengages primary fan.
  • Secondary Fan Control Switch: Off/Manual/Automatic Selector Switch
                                             Disengages, manually engages or automatically engages secondary fan.
  • Alarm Engaged: Red Indicator Light
                                             Illuminates when alarm signal is active & flashes when alarm signal is disabled
  • Alarm Signal Bypass Switch: On/Off Selector Switch
                                            Enables or disables alarm signal.

Bebco Model WDP and RDP Whisper Drive™ Pressurization Units feature all necessary indicators and controls to maintain room or building pressurization or outward velocities through openings automatically upon loss of pressure.

Operation is easy, beginning with startup. Once doors are sealed and the secondary fan control switch is placed in its automatic mode, the unit is started by engaging the primary fan control switch.

The green primary fan engaged indicator will then illuminate to indicate the unit is running, as it establishes a safe pressure within the room automatically. From that point forward, the unit maintains NFPA 496 Code compliance with no need for further adjustments! If pressure is lost, the secondary fan will engage and the alarm signal will be activated immediately or as permitted by settings of their separate corresponding delay timers and the red alarm engaged indicator will illuminate to confirm loss of pressure.

When doors must be left open for a prolonged period of time, the secondary fan control switch may be placed in its manual mode and the alarm signal bypass switch may be used to disable the alarm signal, which in turn will be indicated by flashing of the red alarm engaged indicator. In essence, you’ll find our pressurization units extremely efficient and easy to operate, but for more information on how to utilize these controls to your benefit, please contact a Bebco Sales