Device passport 04
A pressure vacuum breaker is the raised, testable irrigation assembly
Identify a PVB by its bonnet, air inlet, shutoffs, test cocks, elevation, and irrigation placement before diagnosing leaks or freeze damage.
A PVB protects against backsiphonage and is commonly used on irrigation. It is testable and can remain under pressure, unlike a basic atmospheric vacuum breaker.
Never cap the air inlet. Active discharge, a cracked bonnet, or freeze damage needs isolation through the correct procedure and qualified service.
Interactive check
Turn observations into a next step
This narrows the route. It does not replace an on-site test, manufacturer instructions, or local requirements.
Evidence sequence
Move in this order
- 01
Confirm the model
Record the manufacturer, model, size, and approval markings.
- 02
Map the installation
Note elevation, valves, test cocks, irrigation zones, and freeze exposure.
- 03
Choose leak, test, or installation path
The task determines whether local testing and filing apply.
Identification notes
What to look for
- Two shutoff valves and test cocks indicate a testable assembly.
- The bonnet and air inlet sit above the main body.
- The installation is usually elevated above downstream irrigation piping.
Safe observations
What you can check without taking it apart
- Photograph the complete assembly.
- Keep the bonnet vent open.
- Record recent freezing and irrigation startup.
Stop conditions
Move to qualified help when
- Cracked body or bonnet
- Continuous flow
- Unknown isolation
- Commercial or fire-service connection
Boundary check
Do not confuse this path with
- An AVB normally has no field test cocks.
- A hose-bib breaker threads directly to a faucet.
- An RPZ has a relief zone below an inline body.
Official local layer
Your utility sets the rule
Manufacturer installation instructions and local plumbing or utility rules control elevation, testing, and service.
Evidence ledger
What this decision path is built on
Manufacturer installation instructions and local plumbing or utility rules control elevation, testing, and service.
- 01U.S. EPA · EPA-CCC-001Cross-Connection Control ManualBackflow, backsiphonage, device families, hazard protection, testing, and program responsibility. Verified 2026-08-02.
- 02Watts · WATTS-PVB-800M4Series 800M4 pressure vacuum breaker manualPVB installation, periodic testing, freeze protection, and service limitations. Verified 2026-08-02.
Continue the case
Related next steps
CONTENT REVIEWED · 2026-08-02