Conbraco Maintenance Documents:

Double Check Valve Assemblies
Double Check Detector Series 40-100Series 1/2 – 10 inches
Pressure and Spill-Resistant Vacuum Breaker Assemblies
Model 40-5001/2 – 2 inches
Model 4V-5001/2 – 2 inches
Model 4W-5001/2 – 2 inches

Reduced Pressure Principle
Valve Assemblies

Models 40-200  Series1/4″ – 10″. Also includes RPDA.
4D-200 Model RPZ and
4D-700 Model RPDA
2 1/2 – 10 inches

Freeze Protection Valve: