Installing a pressure-vacuum breaker on your irrigation system is an important step to prevent backflow and protect your water supply from contamination. While it may seem intimidating, with the right tools and a bit of patience, it can be a straightforward DIY project. Here is a comprehensive guide on everything you need to know about installing a pressure-vacuum breaker for your sprinkler or irrigation system.
What is a Pressure-Vacuum Breaker?
A pressure-vacuum breaker, also known as a backflow prevention device, is a mechanical valve designed to stop backflow and prevent contaminated water from flowing backwards into the drinking water supply.
It allows water to flow in one direction, while blocking any potential backflow. Pressure-vacuum breakers contain an independent internal spring-loaded disc that seals off the water supply if a drop in pressure occurs. This prevents cross-contamination between the irrigation system and the potable water source in the event of a backflow episode.
Why Do You Need a Pressure-Vacuum Breaker?
Installing a PVB on your irrigation system serves an important purpose:
- Prevents Backflow – It stops contaminated water from reversing flow and getting sucked back into the clean water supply. This can happen if pressure drops in the municipal system.
- Complies with Codes – Most plumbing codes require backflow prevention devices for irrigation systems connected to a potable water source. Having a PVB brings your system up to code.
- Peace of Mind – You can rest easy knowing your drinking water is protected from chemicals, dirt, bacteria, and other contaminants that could backflow from your lawn or garden.
Failing to install backflow prevention is extremely risky and could result in harm, sickness, or even death in a worst case scenario.
PVB Valve Types and Sizes
Pressure vacuum breakers come in a range of sizes and types to fit different irrigation system requirements. Some key points:
- Sizes – Common residential sizes are 3/4 inch, 1 inch, and 1 1/4 inch. Measure your pipe diameter and match accordingly.
- Types:
- Atmospheric Vacuum Breakers – only suitable for systems under continuous pressure.
- Pressure Vacuum Breakers – suitable for systems under constant pressure or intermittent operation. Most common type for irrigation.
- Reduced Pressure Zone (RPZ) Valves – used for high hazard installations. Provides maximum backflow prevention.
- Position – Must be installed higher than the highest sprinkler head on the system. Requires a 12 inch clearance minimum.
Choose the appropriately sized PVB for your pipe diameter and type of irrigation system. Consult manufacturer specs for flow rate capacities. An irrigation specialist can help pick the optimal backflow preventer.
PVB Installation Location
Proper placement is critical when installing a pressure vacuum breaker:
- Install above ground – either vertically or horizontally.
- Position higher than the highest sprinkler head or emitter – minimum of 12 inches above. This allows the PVB to work properly.
- Allow easy access for testing and maintenance. Do not block or cover.
- Place indoors or in a ventilated enclosure if temperatures regularly drop below 40°F. PVBs cannot have water freeze inside them.
- Avoid direct sunlight exposure which can degrade plastic components over time.
Pick a location like a garage wall, carport column, or on the side of a fence or deck. The closer to the water meter, the better.
Proper installation positioning for a pressure vacuum breaker.
Gather the Right PVB Installation Tools
Installing a pressure vacuum breaker is a straightforward DIY project. You’ll need some standard irrigation and plumbing tools:
- Tape measure
- Adjustable wrenches
- Additional wrenches for holding pipes
- PTFE plumber’s tape
- Hose clamps or crimp fittings
- Drill and bits for mounting (optional)
You’ll also need pipe fittings to match your existing irrigation piping. Having some extra 90° and 45° elbows and unions on hand is also handy for small adjustments.
How to Install a PVB Valve
Follow these steps to properly install a pressure vacuum breaker valve:
Step 1: Turn Off Main Water Supply
Shut off the main water supply valve that feeds water to your irrigation system. Relieve pressure by opening an irrigation zone valve.
Step 2: Cut Pipe
Determine the installation location per the height and placement instructions. Measure and cut the main irrigation line in order to fit the PVB valve.
You’ll want around 4″ of straight pipe on each end of the PVB valve. Make clean cuts with a pipe cutter.
Step 3: Prepare and Connect Fittings
Deburr the cut pipe ends and apply plumber’s tape. Connect elbows and adapters to match the inlet and outlet of the PVB to your existing pipework.
Hand tighten connections but do not fully tighten yet.
Step 4: Install Valve
Place the PVB valve between the pipe fittings. Ensure proper directional water flow through the valve by verifying the directional arrow on the valve matches the water source.
Position vertically for optimal protection and drainage.
Step 5: Tighten Fittings
With the valve in place, finish tightening all pipe fittings with wrenches. Use a second wrench to hold the valve body while tightening to avoid damage.
Step 6: Secure Valve
Secure the valve body directly to the wall using screw or bolt mounts. This prevents stress on the valve.
Step 7: Turn Water On and Test
Turn the main water supply back on slowly. Inspect for leaks and tighten any fittings as needed. Test the valve by opening a zone – water should flow through normally.
Step 8: Annual Testing
PVB valves must be tested annually and rebuilt or replaced every 5 years. Mark your calendar annually to test the valve springs, seals, and caps.
Hire a certified backflow technician if needed. Keep all service records.
And that’s it! With the pressure vacuum breaker installed you can enjoy peace of mind knowing your water supply is protected from backflow contamination.
Frequently Asked Questions About Pressure-Vacuum Breakers
Do I need a permit to install a PVB?
Most areas do not require a permit to install a PVB valve on an existing irrigation system. However, some municipalities require a permit if installing a new irrigation system. Check with your local building codes department.
Where can I find pressure-vacuum breakers for sale?
PVB valves are sold at most major hardware stores and irrigation supply retailers. You can also find them through online retailers. Look for models approved by ASSE, AWWA, and UPC/IAPMO.
How far away from a water source should a PVB be installed?
PVB valves should be installed as close as possible to the water source feeding the irrigation system, ideally within 10 feet. Maximum distance is 30 feet.
Can I install a pressure vacuum breaker on PVC pipe?
Yes, PVB valves can be installed on PVC irrigation pipes as long as proper adapters are used. Use threaded PVC adapters to connect to the threaded PVB inlet and outlet.
How do I know if my PVB needs servicing?
Inspect annually. Indications it needs service: leaking from cap, debris clogging relief valve seat, damaged or missing components, failed testing. Most PVBs require full rebuilding or replacement every 5-7 years.
What is the cost to maintain and test PVBs?
Annual testing costs $50 – $150. Rebuilding or replacing valves every 5-7 years costs $150 – $350. Hiring a backflow certification specialist is recommended.
Can I install a pressure-vacuum breaker on my own irrigation system as a DIY project?
Yes, as long as you follow all applicable plumbing codes. Installing a PVB valve only requires basic tools and DIY skills. Make sure you test for proper operation after completing the installation.
Prevent Backflow and Protect Your Water
Installing a pressure-vacuum breaker is a straightforward project that can complete in just an hour or two with some plumbing know-how. While codes require them on irrigation systems, they also provide immense value by protecting your family and home against the risks of backflow contamination. Invest a small amount of time and money upfront to safeguard your water for years to come.