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How To Install a Vacuum Breaker

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A pressure vacuum breaker is an important part of any irrigation system and is required by most cities because it prevents contamination of the potable water supply through the irrigation system. If you have an irrigation system you should have a pressure vacuum breaker. You can call the local building code office to find out if it is required. Even if it is not required in your area it may be a good idea to install one. Learn how to install a vacuum breaker yourself to save on the cost of installation.

Pressure vacuum breaker installation can be is easy, especially if you have a PVC main water line. Usually you want the PVB to be close to the sprinkler valves and right after a stop and waste valve especially if you live in a colder climate. This vacuum breaker installation configuration will help drain the line down when you shut down the irrigation system for the winter.

How to install a vacuum breaker:

  1. Dig up the area between the valves and the main sprinkler shut off. If you do not have a shut off valve here is might be a good idea to install one. To install a pressure vacuum breaker you should not need more that 12” to 18” of space.

  2. Make sure the pressure vacuum breaker valve is the same size as the pipe. Downsizing the pipe at this juncture can cause some water volume problems throughout the sprinkler system as the water flow becomes restricted by the smaller pipe size.

  3. Get a parts list together. If you are doing the installation with PVC the parts list should consist of something like three 90’s, two male adapters, pipe, glue, primer, Teflon tape, and maybe unions if you want to be able to replace the vacuum breaker easily in the future or to remove it for harsh winters.

  4. Apply Teflon tape to the adapters and screw them into the PVB valve so you that can see exactly how much room you will need between the inlet and the outlet with a PVC 90 pointing down from the outlet. If you have plenty of room to work with the installation should be easy. If you have limited space this step will help you figure out what you are dealing with. Have a plan before cutting the existing pipe for the installation.

  5. Mark the PVC main water line and cut it to suit your pressure vacuum breaker valve. The PVB will need to be a minimum of 12” higher than highest outlet measured from the center of the middle ball valve.

  6. Measure and cut the lengths of pipe necessary to install the vacuum breaker at the correct height. When cutting the PVC risers leave them a little longer than necessary since you can always cut them shorter later.

    Primer and glue the PVC 90’s onto the pipe in the ground first with the pipe risers. Use a level to help ensure that the risers are coming straight up.

  7. Measure and install the unions. Measure the length of the small piece of pipe that will go between the PVB and the outlet 90. Cut and glue the pipe and 90 to the PVB adapter.

    The final step is to glue the vertical pieces straight down into the fittings. Dry fit if you want help with lining up and leveling the valve but do not forget to glue the joints. This is why it is always a good idea to use the colorful glue so you can tell which joints have glue and which do not.

    Note: Make sure to install the pressure vacuum breaker in the right direction. There should be a flow arrow on the PVB.

  8. Allow the joints dry for the amount of time noted on the glue that you used. Leave both valves off on the pressure vacuum breaker. Turn the main sprinkler valve on slowly, then turn on the PVB one valve at a time unless instructed otherwise by the manufacturer. Check for leaks at the joints before backfilling.

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