Thermal Products Corp Thermal Products Corp


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The VARI-FLOW™ diffusers are the latest in state-of-the-art VAV technology. The VARI-FLOW 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-FLOW™ architectural VFS "D" diffuser operates the same as a standard VFS, but is designed to accept a ceiling tile. This allows the architect to match the existing ceiling tile pattern creating a harmonious appearance with the ceiling system.*

The VARI-FLOW™ (VFS 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 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 energy provided by the thermal element is coupled to an efficient operating mechanism to operate the damper on the unit.


  • Totally self contained control system

  • Warm-up feature (optional) 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 and new systems

  • Calibrated VAV cooling set point

  • No controls contracts

  • Low profile induction guide


*Refer to VFSA94-100 for more detailed information on VFS.