Vacuum breaker valves introduce air into the system to prevent back-siphoning and protect a water supply from hazardous contaminants. Pressure vacuum breakers consist of a check valve and air inlet to create an air gap and prevent backflow for continuous inlet-side pressure applications. Atmospheric vacuum breakers have a vent that's sealed by pressure applied to the outlet side of the valve to create negative pressure which introduces air into the system and prevents back-siphoning. Hose bibb vacuum breakers screw onto hose bibbs and protect water sources from contaminants, such as pesticides and cleaners. Thermostatic air vent vacuum breakers release steam from heat exchangers and steam coils and have an inlet that introduces air into the system to back-siphoning. Vacuum breaker repair parts and kits keep equipment in working condition.