The Insert 3-point Thermostat Control Wire command is used to insert a thermostat control wire on the drawing using three points to define an arc. Thermostat control wires are for drafting purposes only and are not linked to the database. The thermostat control wire is inserted as a standard CAD polyline and can be modified using standard CAD commands.
To insert a 3-point thermostat control wire, go to
Ribbon: DM HVAC->Drafting-> 
Insert 3-point Thermostat Control Wire
Pulldown Menu: DM HVAC->Drafting Tools->Insert 3-point Thermostat Control Wire
You will be prompted to specify the starting point of the thermostat control wire.
Start point:
You then will be prompted to specify the second point of the thermostat control wire.
To point:
You will then be prompted to specify the end point of the thermostat control wire.
To point:
A polyline will be inserted on the drawing using the three specified points.