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  • Totally self contained control system

  • Warm-up feature provides constant volume heating

  • Self-Powered, thermally actuated, individual VAV room control

  • Variable discharge area

  • Heating and cooling with automatic change over

  • Reduces installation costs

  • All controls accessible from unit face

  • Saves energy on existing a new systems

  • Calibrated VAV cooling setpoint

  • No controls contracts

  • Low profile induction guide

The VARI-FLOWTM diffusers are the latest in state-of-the-art VAV technology.  The VARI-FLOWTM square diffuser is a VAV ceiling diffuser designed for a grid ceiling system.  It functions as an air diffuser, a zone of temperature control, and a VAV box.

The VARI-FLOWTM square (VFS-24 series) provides individual temperature control for cooling at each diffuser, adjustable from 70 to 78 degrees Fahrenheit.  This will provide constant uniform temperature within a large office space or in smaller individual offices regardless of heat load conditions.  The net result is uniform comfort and energy saving as none of the conditioned space is over or under cooled.

The VFS-24 diffuser is totally self-contained and self-powered by a thermal element.  The thermal element functions in the unit as the thermostat and “motor” to power the unit. The principle of operation of the element is a basic and simple one, that of thermal expansion when a substance changes state, in this case from a liquid to a solid.  The element uses a mixture of synthetic wax and copper powder for the medium, blended to respond in the desired operating range.  The thermal element has a long proven history of reliability.

Designed in 1937, they have been in use for 50 years in a variety of industries. The elements have been used in the HVAC industry on hydronic and steam valves, in the auto-mobile industry on radiator thermostats, and air pollution controls.

The energy provided by the thermal element is coupled to an efficient operating mechanism to operate the damper on the unit.  The temperature response or differential is equal to or less than electric or pneumatic thermostats.

Installation is as quick and easy as a conventional ceiling diffuser, as there are no electric or pneumatic connections.