A pressure vacuum breaker (PVB) is a type of backflow prevention device used to protect potable water supplies from contamination or pollution due to backflow. It is commonly used in irrigation systems, where it prevents water from flowing backward into the main water supply. The PVB consists of a check valve, an air inlet valve, and test cocks. The check valve allows water to flow in one direction, while the air inlet valve opens to admit air into the system when the pressure drops, preventing back-siphonage. Here's how it works: 1. **Normal Operation**: When the system is pressurized, water flows through the check valve, which remains open due to the pressure. The air inlet valve stays closed because the water pressure keeps it sealed. 2. **Backflow Prevention**: If the pressure in the system drops (e.g., due to a pipe burst or a sudden demand elsewhere), the check valve closes to prevent water from flowing backward. Simultaneously, the air inlet valve opens, allowing air to enter the system. This breaks the vacuum and prevents contaminated water from being siphoned back into the potable water supply. 3. **Restoration**: When normal pressure is restored, the air inlet valve closes, and the check valve reopens, allowing water to flow in the intended direction. PVBs are typically installed above ground and at least 12 inches above the highest downstream point to ensure proper operation. They are suitable for low to moderate hazard applications and are effective against back-siphonage but not back pressure. Regular maintenance and testing are essential to ensure their reliability and functionality.

A pressure vacuum breaker (PVB) is crucial for sprinkler systems because it serves as a backflow prevention device, ensuring the safety and integrity of the potable water supply. Backflow can occur when there is a sudden drop in water pressure, causing contaminated water from the sprinkler system to flow back into the clean water supply. This can introduce pesticides, fertilizers, and other harmful substances into the drinking water, posing health risks. The PVB is designed to prevent this by allowing water to flow in only one direction. It consists of a check valve and an air inlet valve. When the sprinkler system is in use, the check valve opens to allow water to flow through. If a backflow condition occurs, the air inlet valve opens, breaking the vacuum and allowing air into the system, which stops the reverse flow of water. Additionally, PVBs are typically installed above ground and above the highest point in the sprinkler system, ensuring they function effectively. They are relatively easy to maintain and inspect, making them a practical choice for residential and commercial irrigation systems. By preventing contamination, PVBs help comply with local plumbing codes and regulations, which often mandate backflow prevention devices for irrigation systems. This compliance is essential for avoiding legal and financial penalties. In summary, a pressure vacuum breaker is important for sprinkler systems because it protects the potable water supply from contamination, ensures compliance with regulations, and maintains the overall safety and health of the water system.

1. **Select Location**: Choose a location that is above ground and close to the water source. Ensure it is at least 12 inches above the highest downstream outlet. 2. **Shut Off Water Supply**: Turn off the main water supply to prevent any water flow during installation. 3. **Drain the System**: Open the lowest faucet or valve in the system to drain any remaining water. 4. **Cut the Pipe**: Use a pipe cutter to cut the pipe where the pressure vacuum breaker will be installed. Ensure the cut is clean and straight. 5. **Install Shut-Off Valves**: Attach shut-off valves on both sides of the cut pipe to allow for future maintenance. 6. **Attach Fittings**: Use appropriate fittings (e.g., PVC, copper, or galvanized) to connect the pressure vacuum breaker to the pipe. Apply Teflon tape or pipe dope to threaded connections to ensure a watertight seal. 7. **Mount the Breaker**: Position the pressure vacuum breaker vertically and attach it to the fittings. Ensure the arrow on the device points in the direction of water flow. 8. **Secure the Device**: Use brackets or straps to secure the pressure vacuum breaker to a stable surface to prevent movement. 9. **Check for Leaks**: Slowly turn on the water supply and check for leaks at all connections. Tighten any loose fittings if necessary. 10. **Test the System**: Open downstream valves to ensure proper water flow and check the operation of the pressure vacuum breaker. 11. **Insulate (if necessary)**: In colder climates, insulate the device to protect it from freezing temperatures. 12. **Regular Maintenance**: Periodically check the device for proper operation and perform maintenance as needed.

1. **Regular Inspection**: Check for leaks, corrosion, and wear. Inspect the assembly for any visible damage or debris. 2. **Annual Testing**: Conduct annual backflow prevention tests by a certified professional to ensure proper operation and compliance with local regulations. 3. **Cleaning**: Remove debris from the air inlet valve and check valve. Clean the internal components to prevent blockages. 4. **Winterization**: In colder climates, drain the system before winter to prevent freezing. Insulate or remove the breaker if necessary. 5. **Valve Operation**: Ensure the shut-off valves open and close smoothly. Lubricate if needed to maintain functionality. 6. **Check Valve Maintenance**: Inspect the check valve for proper sealing. Replace worn or damaged parts to prevent backflow. 7. **Air Inlet Valve Maintenance**: Ensure the air inlet valve opens and closes correctly. Clean or replace if it sticks or leaks. 8. **Gasket and Seal Inspection**: Check gaskets and seals for wear or damage. Replace them to maintain a proper seal and prevent leaks. 9. **Pressure Testing**: Test the pressure to ensure it is within the recommended range for optimal operation. 10. **Documentation**: Keep records of maintenance, inspections, and tests for compliance and future reference. 11. **Professional Servicing**: Engage a certified technician for complex repairs or if the device fails testing. 12. **Replacement**: Replace the pressure vacuum breaker if it consistently fails tests or shows significant wear. 13. **Environment Check**: Ensure the installation environment is free from conditions that could cause damage, such as excessive moisture or chemical exposure.

1. **Visual Inspection**: Check for any visible damage, leaks, or corrosion on the pressure vacuum breaker (PVB). Ensure all components are intact and securely connected. 2. **Shut Off Water Supply**: Turn off the water supply to the PVB. This is typically done by closing the main shut-off valve upstream of the device. 3. **Relieve Pressure**: Open a downstream valve or faucet to relieve any pressure in the system. This ensures accurate testing conditions. 4. **Attach Test Kit**: Connect a backflow test kit to the test cocks on the PVB. The test kit usually includes hoses and gauges to measure pressure. 5. **Test Check Valve**: - Open the test cock on the inlet side of the PVB. - Record the pressure reading on the gauge. - Close the inlet shut-off valve. - Observe the gauge for any drop in pressure, which indicates a leaking check valve. 6. **Test Air Inlet Valve**: - Open the test cock on the outlet side of the PVB. - Slowly open the outlet shut-off valve. - The air inlet valve should open, allowing air to enter and the pressure to drop to atmospheric level. - If the air inlet valve does not open, it may be stuck or faulty. 7. **Check for Leaks**: With the test kit still attached, check for any leaks around the PVB, especially at the test cocks and shut-off valves. 8. **Restore System**: Once testing is complete, remove the test kit, close all test cocks, and restore the water supply by opening the main shut-off valve. 9. **Final Inspection**: Ensure the PVB is functioning correctly with no leaks or pressure issues. Recheck all connections and components. 10. **Record Results**: Document the test results, including any issues found and corrective actions taken.