The Caleffi 573009A is an AutoFill Combo with a 1/2 in sweat inlet x 1/2 in npt outlet connection, pre-assembling an automatic filling valve with an ASSE 1012 dual-check backflow preventer with atmospheric vent to feed and protect a hydronic system in one code-compliant unit.
Product data compiled from Caleffi North America technical documentation. Last reviewed July 2026.
Key Features
Fill Valve + Backflow in One
Pre-assembled AutoFill filling valve with an ASSE 1012 dual-check backflow preventer with atmospheric vent.
Code-Compliant Boiler Feed
Satisfies typical residential boiler feed-water code requirements in a single compact unit.
Pre-Adjustable Fill Pressure
Set the target system fill pressure; the valve reduces and holds it automatically.
Lead-Free Construction
Suitable for connection to the potable water supply.
Technical Data
| Function | Combination automatic filling valve and backflow preventer |
|---|---|
| ASSE listing | ASSE 1012 |
| Connection | 1/2 in sweat inlet x 1/2 in npt outlet |
| Adjustment pressure range | 3-60 psi |
| Factory pressure setting | 15 psi |
| Maximum operating pressure | 175 psi |
| Maximum upstream pressure | 175 psi |
| Medium temperature range | 40-150 °F |
| Pressure gauge scale | 0-60 psi |
| Material | brass |
Documentation
Technical brochureRelated Products
Frequently Asked Questions
It is an AutoFill Combo: an automatic filling valve pre-assembled with a backflow preventer, feeding a hydronic system while protecting the potable supply.
An ASSE 1012 dual-check backflow preventer with intermediate atmospheric vent, typical for residential boiler feed.
Most codes require an ASSE 1013 RPZ when the system contains glycol or chemical treatment (high hazard); ASSE 1012 covers typical low/intermediate-hazard residential boiler feed. Confirm with your local authority.
- Type:
- Filling Valve & Backflow Combo
- ASSE Standard:
- ASSE 1012
- Series:
- AutoFill Combo
- Connection Type:
- Sweat
- Connection Type:
- NPT Threaded
- Connection Size:
- 1/2 in
