Diffusers

This section describes the options available in the Diffusers group in the Design Master HVAC Options dialog box.

Show arrows on 4 way throw patterns: Whether throw arrows are shown on diffusers when they are first inserted on the drawing. Once a diffuser is inserted on the drawing, use the Insert Throw Arrow and Remove Throw Arrow commands to modify the throw arrows that are displayed. Changing this option will not affect throw arrows on diffusers already on the drawing.

•	Single line (callout-CFM): A single line listing the diffuser callout and the airflow.

•	Two line (callout, CFM): Two lines of text separated by a line listing the callout on the first line and the airflow on the second.

•	Two line (callout, CFM, neck size): Two lines of text separated by a line listing the callout on the first line and the airflow and neck size on the second.

•	Three line box: A box with three lines of text listing the callout on the first line, the neck size on the second, and the airflow on the third.

•	Three line box (rounded): A box with round corners with three lines of text listing the callout on the first line, the neck size on the second, and the airflow on the third.

•	Circle: A circle with two lines of text listing the callout on the first line and the airflow on the second.

•	Square with neck dimension: A box with a single line listing the neck size, the callout, and the airflow.

•	Hexagon: A hexagon with two lines of text listing the callout on the first line and the airflow on the second.

•	Triangle: A triangle with the callout listed inside it and the airflow listed below.

•	CFM only: The airflow is listed. No callout or neck size is displayed.

•	Show neck, face, and throw: Two lines of text separated by a line listing the neck size, face size, and callout on the first line and the airflow and throw pattern on the second.

•	Dome: A dome with two lines of text listing the callout on the first line and the airflow on the second.

•	Flow arrow underline: Two lines of text separated by a line listing the callout on the first line and the airflow on the second. The line between the two lines of text connects to the leader and points in the direction of the airflow into or out of the diffuser.

•	Custom block: The callout is inserted using a custom block. See the Creating a Custom Diffuser Callout Block article in the knowledge base for more information about how to create a custom block.

•	Custom single line: A single line of with custom text. The text is set using the Custom diffuser callout format options below.

•	Custom two line: Two lines of text separated by a line. The text in the two lines is set using the Custom diffuser callout form line 1 and Custom diffuser callout form line 2 options below.

Custom diffuser callout format line 1: The format used for the top line of the diffuser callout when the Diffuser callout option is set to Custom two line. See the Custom Diffuser Callout Codes section below for more information about the values that can be automatically inserted in the label.

Custom diffuser callout format line 2: The format used for the bottom line of the diffuser callout when the Diffuser callout option is set to Custom two line. See the Custom Diffuser Callout Codes section below for more information about the values that can be automatically inserted in the label.

Custom diffuser callout format (supply): The format used for supply diffuser callouts when the Diffuser callout option is set to Custom single line. See the Custom Diffuser Callout Codes section below for more information about the values that can be automatically inserted in the label.

Custom diffuser callout format (return): The format used for return diffuser callouts when the Diffuser callout option is set to Custom single line. See the Custom Diffuser Callout Codes section below for more information about the values that can be automatically inserted in the label.

•	Same as supply: Return diffuser callouts will use the Custom diffuser callout format (Supply) option value.

Custom diffuser callout format (exhaust): The format used for exhaust diffuser callouts when the Diffuser callout option is set to Custom single line. See the Custom Diffuser Callout Codes section below for more information about the values that can be automatically inserted in the label.

•	Same as supply: Exhaust diffuser callouts will use the Custom diffuser callout format (Supply) option value.

Diffuser callout insertion: How diffuser callouts are inserted when a new diffuser is inserted on the drawing. Once the diffuser and diffuser callout are inserted on the drawing, use the Insert or Move Callout and Remove Callout commands to modify the callouts. Changing this option will not affect diffusers and diffuser callouts already on the drawing.

•	Automatic: The diffuser callout is automatically inserted to the right of the diffuser.

•	Manual: You are prompted to specify the location of the diffuser callout after the diffuser is inserted.

•	Not inserted: Diffusers are inserted without diffuser callouts.

Diffuser CFM label format: How the airflow value for a diffuser is displayed in the callout. The $CFM code will be replaced with the actual CFM value of the diffuser. The $LPS code will be replaced with the airflow in liters per second. Other text will be displayed exactly as it is entered.

The default value for this option is $CFM, which displays only the CFM value for the diffuser.

The most common change to this option is to set it to $CFM CFM, which displays the CFM value with a "CFM" label.

Another common change is to include the $LPS code to display the airflow in metric units.

The Custom diffuser callout options use special codes to insert information about the diffuser in the callout text.

The $CFM code will be replaced with the diffuser airflow. The format for the replacement string is based upon the Diffuser CFM Label format option.