The Caleffi NA573022 is the NA573 replenishment water treatment filling unit with a 1/2 in NPT connection with integral pressure gauge, combining an AutoFill filling valve, backflow preventer, isolation valves and a color-changing demineralization filter to fill a sealed hydronic system with pressure-regulated, demineralized make-up water.
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.
Integral Pressure Gauge
A built-in gauge shows system fill pressure at a glance.
Lead-Free Construction
Suitable for connection to the potable water supply.
Technical Data
| Function | Combination automatic filling valve and backflow preventer |
| Connection | 1/2 in NPT |
| Pressure gauge | Included |
| Maximum upstream pressure | 125 psi |
| Maximum working temperature | 100 °F |
| Nominal flow rate | 1 gpm |
Documentation
Technical brochureRelated Products
- Caleffi 573002A 1/2 in ASSE 1012 Fill + Backflow Combo
- Caleffi 573006A 1/2 in ASSE 1012 Fill + Backflow Combo
- Caleffi 573007A 1/2 in ASSE 1012 Fill + Backflow Combo
- Caleffi 553542A 1/2 in Auto Fill Valve
Frequently Asked Questions
What is the Caleffi NA573022?
It is an AutoFill Combo: an automatic filling valve pre-assembled with a backflow preventer, feeding a hydronic system while protecting the potable supply.
Which backflow preventer is included?
An ASSE 1012 dual-check backflow preventer with intermediate atmospheric vent, typical for residential boiler feed.
When do I need ASSE 1013 instead of ASSE 1012?
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
- Series:
- AutoFill Combo
- Pressure Gauge:
- Included
- Connection Type:
- NPT Threaded
- Connection Size:
- 1/2 in
