The Caleffi 573409A is a FlowShield DuC-AV dual check backflow preventer with atmospheric vent and a 1/2 in sweat connection, listed to ASSE 1012 for intermediate-hazard protection of potable water lines.
Product data compiled from Caleffi North America technical documentation. Last reviewed July 2026.
Key Features
ASSE 1012 Intermediate Hazard
Listed to ASSE 1012 for intermediate-hazard potable water protection.
Atmospheric Vent Port
An intermediate atmospheric vent discharges to drain if the upstream check fails, adding a layer of protection over a plain dual check.
Two Serviceable Checks
Two independent inline check valves close automatically under backflow conditions.
Lead-Free / NSF Certified
DZR low-lead brass, certified to NSF/ANSI/CAN 61 and NSF/ANSI/CAN 372 for potable water.
1/2 In Sweat Connection
1/2 in sweat connection.
Technical Data
| Function | Dual check backflow preventer with atmospheric vent |
|---|---|
| ASSE listing | ASSE 1012 |
| Connection | 1/2 in sweat |
| Body material | DZR low-lead brass |
| Maximum operating pressure | 175 psi |
| Medium temperature range | 32 - 210 °F |
| Lead-free compliance | NSF/ANSI/CAN 61 and NSF/ANSI/CAN 372 |
Documentation
Technical brochureRelated Products
Frequently Asked Questions
It is a dual check backflow preventer with atmospheric vent for intermediate-hazard potable water protection.
If the upstream check valve fails, the intermediate vent opens to atmosphere and discharges to drain, signaling the fault and adding protection over a plain dual check.
ASSE 1012, and it is lead-free per NSF/ANSI/CAN 372.
This model has a 1/2 in sweat connection.
- Type:
- Dual Check Valve with Atmospheric Vent
- Series:
- FlowShield
- ASSE Standard:
- ASSE 1012
- Connection Type:
- Sweat
- Connection Size:
- 1/2 in
