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Device passport 02

Identify the vacuum breaker by where air can enter

Separate hose-bib, atmospheric, and pressure vacuum breakers before treating a drip or discharge as a failure.

Working verdict

Vacuum breakers stop backsiphonage by admitting air. A hose faucet attachment, an atmospheric breaker, and a testable pressure vacuum breaker are different products with different limits.

Simplified pressure vacuum breaker with raised bonnet and air inlet
FIELD VIEW Use the shape as a clue. Confirm the model label before service.
Before you act

Do not cap an air inlet or relief opening to stop a leak. That opening is part of the safety function.

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.

Where is the device installed?

Evidence sequence

Move in this order

  1. 01

    Find the air inlet

    Look for a bonnet, poppet, or vent designed to admit air.

  2. 02

    Check the installation height

    PVBs are commonly elevated; hose-bib devices are attached directly to a faucet.

  3. 03

    Record the model

    The manufacturer model tells you whether the unit is testable and which service information applies.

Identification notes

What to look for

  • A PVB normally sits above downstream irrigation piping with shutoffs and test cocks.
  • An AVB is simpler and must not be treated like a continuously pressurized testable assembly.
  • A hose-bib breaker threads directly onto an outdoor faucet and is much smaller.

Safe observations

What you can check without taking it apart

  • Turn off the downstream irrigation zone and observe whether discharge stops.
  • Look for freeze cracks without disassembly.
  • Check whether debris is visible around an exposed vent.

Stop conditions

Move to qualified help when

  • A cracked bonnet or body
  • Continuous uncontrolled flow
  • Freezing conditions around active discharge
  • A device serving a commercial or fire-related system
Get help with this next step

Boundary check

Do not confuse this path with

  • An RPZ has a relief zone beneath a larger inline body.
  • A pressure regulator changes pressure but does not provide the same cross-connection protection.
  • A sewer backwater valve is installed in drainage piping.

Official local layer

Your utility sets the rule

The shape is a screening clue, not a certification. Use the model label and the local utility rule for the final decision.

Verified utility matches: 96

Evidence ledger

What this decision path is built on

The shape is a screening clue, not a certification. Use the model label and the local utility rule for the final decision.

  1. 01
    U.S. EPA · EPA-CCC-001Cross-Connection Control ManualBackflow, backsiphonage, device families, hazard protection, testing, and program responsibility. Verified 2026-08-02.
  2. 02
    Watts · WATTS-PVB-800M4Series 800M4 pressure vacuum breaker manualPVB installation, periodic testing, freeze protection, and service limitations. Verified 2026-08-02.
  3. 03
    Watts · WATTS-AVB-288ASeries 288A atmospheric vacuum breakerAtmospheric vent operation and non-continuous-pressure application limits. Verified 2026-08-02.
  4. 04
    Watts · WATTS-HOSE-008Series 8 hose connection vacuum breakerHose-thread device identification, backsiphonage protection, and service literature. Verified 2026-08-02.

Continue the case

Related next steps

ProblemVacuum breaker leakingDeviceCompare other backflow preventersDecisionRepair or replace

CONTENT REVIEWED · 2026-08-02