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Ventilation or Psychrometric Airflow Values are 0

Monday, January 27th, 2014

Problem: When viewing HVAC building load calculations, in the Ventilation Schedule section or Psychrometric section, the supply air volume and outside air volume are 0.

Cause: The Use Actual Supplied CFM in Ventilation and Psychrometric Calculations option is enabled in the Project Info command and no supply diffusers have been inserted on the drawing.

Because the option is enabled and there are no supply diffusers, the supply airflow is set to 0. The rest of the calculations are wrong because that airflow is wrong.

Solution: There are two possible solutions to the problem.

1. Insert supply diffusers on the project in the rooms.

2. Disabled the Use Actual Supplied CFM in Ventilation and Psychrometric Calculations option using the DM HVAC->Building Definition->Project Info command.

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