Setting CFM

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Design Master HVAC can automate much of the process of determining the required CFM for a room and setting the supplied CFM to equal the required CFM. Determining the required CFM is done when the load calculations are completed. To set the supplied CFM in a room to equal the required CFM, go to

DM HVAC arrowSet CFM Total arrowIn a Room

Design Master HVAC will prompt you to select a point inside the room. Click inside Office 107. The Set CFM Total in a Room dialog box will appear as shown below.


This dialog box indicates the required CFM as calculated by Design Master HVAC based on the room definition. In this case, the required CFM is 422, while the supplied is 350. To enter a new supplied CFM, type the desired number in the New CFM field. If the default new CFM is left as shown, Design Master HVAC will round this number to the nearest five. For this tutorial, leave the number for New CFM and New Return CFM set to 422 and press OK. Office 107 should now appear as shown below. Note that Design Master HVAC set the supplied CFM to 425 and also automatically adjusted the diffuser R-1 to the diffuser R-2, as R-2 is needed to return 425 CFM of air.


Repeat this process for Offices 105 and 103 as well as for Conference 102. Then, update the Room Attribute Load Calculation Map by running the Display Load Calculation Map command (See Creating Load Calculation Maps for a review of this command). Your drawing should now match the one shown below.


To erase the map, run the Erase Load Calculation Map command. Now that you have inserted the appropriate number and size of diffusers on the drawing for your design, you will insert the diffuser schedule.

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