If you cannot identify an existing symbol inIsoSymbolStyles.dwg to use, you can create a new symbol.
To create a new Iso symbol first open IsoSymbolStyles.dwg and enter bedit at the command prompt to open the Block Editor.
Consider the following suggestions and guidelines when creating your block:
Open a Valve block to identify the scale to used for your new Iso Symbol. All blocks are scaled uniformly during Iso creation (you can set the scale in project setup).
TapPoints are not required. If no TapPoints are defined in the block but a tap is needed, a tap point is automatically created.
Wipeouts can be added to blocks created for annotations (for example: a diamond enclosure annotation block). This is done because annotations can end up on top of skew hatches in the output iso. The wipeouts make the text in the annotation readable by hiding whatever is underneath it.
Flow dependent blocks like check valves and flow arrows can have a flip parameter (parameter + action) in a dynamic block. This provides a flip grip in the Iso drawing. Flip parameters named FlipX and FlipY are used. A flow-arrow or check-valves sets a FLOW attribute in the PCF which can be orientated using the flip grip. If a component is not flow dependent (has no FLOW attribute in the PCF) it will not flip; even if a flip parameter exists in the block definition.
Reducers support flips such that the larger or smaller ends match adjacent components. This assumes that reducers are created with the larger side on the left.
Flanges support flips such that the flanged side faces the flange connection. This assumes that flanges are created with the flanged side on the left.
For valve blocks you can add a point parameter named Operator at the operator location (for example: the center point).
Adding a point parameter CP to define the block center is recommended (but it is not required).