Thermal Products Corp, Mfg. of alternative Vav Diffusers Vav Diffuser Mfg.

Heating: Perimeter Zones Operation


  1. On a drop in temperature below the heating set point of the primary zone control thermostat, the cold supply air control damper will close (a minimum can be set for fresh air requirements).
  2. The hot supply air control damper will begin to open and will adjust to maintain a maximum down stream static pressure. The recommended static pressure is .25"w.g. The static pressure is field adjustablepdf.
  3. Hot supply air (>80 degrees F.) will flow to the Vari-Flow diffusers. A cooling / heating change over sensor in the neck of the Vari-Flow diffusers will change the Vari-Flow diffusers to the heating mode of operation. The Vari-Flow diffuser dampers will position themselves to the field adjustable volume for constant volume heating. The heating volume adjustment of each Vari-Flow diffuser will be set to maintain individual heating comfort levels.
  4. The control thermostat is placed in the area of extreme for the exposure. This is typically the area that requires heating and cooling first and is satisfied last. The area with the zone control thermostat is called the "control zone". The diffusers in the "control zone" will be constant volume diffuser(s). This is done so that there are not two temperature controls in for the same zone. As the exposure starts to approach the control thermostat heating set point, the hot supply air control damper will begin to modulate the volume of hot air to maintain the set-point temperature.

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