Rebuild the assembly you already have instead of replacing the whole valve.
A reduced-pressure backflow preventer protects a potable water supply from cross-connection contamination. When annual testing shows a check valve holding poorly or the relief valve weeping, the assembly has to be brought back into spec — but that rarely means the body, unions, and test cocks are finished. The wear is in the internals.
The Caleffi NA11605 Complete Repair Kit supplies those internals for the ¾-inch 574 FlowShield™ RP. Caleffi identifies NA11605 as the rebuild kit for the ¾-inch models 574050A and 574056A, bringing the primary serviceable components together under one part number.
What Is the Caleffi NA11605?
The NA11605 is a complete rebuild kit for the ¾-inch 574 FlowShield™ RP testable reduced-pressure backflow preventer. Rather than chasing individual replacement pieces across separate line items, a technician orders one kit and has what the assembly needs to be rebuilt and re-tested.
What's Included
For the ¾-inch 574 assembly, Caleffi's parts diagram identifies the rebuild components as:
- Upstream check valve assembly
- Downstream check valve assembly
- Discharge/relief valve assembly
- Discharge valve seat
That covers the internal working components most likely to be flagged during inspection and testing.
Why Use a Complete Repair Kit?
Sourcing internals piecemeal invites the wrong problem: a partial rebuild that still fails its test, or a second trip to the supply house mid-job. Ordering the size-correct kit avoids both.
Practical Advantages
- Simplifies parts ordering to a single part number
- Reduces service downtime on the assembly
- Restores proper valve operation ahead of re-testing
- Maintains an existing 574 installation
- Avoids unnecessary replacement of the complete backflow preventer
Caleffi designed the 574 series with top access to the internal components, which is what makes an in-place rebuild practical rather than a teardown.
Designed for the Caleffi 574 FlowShield™ RP
The 574 FlowShield is a testable reduced-pressure principle assembly built to protect potable water systems from backflow contamination. The ¾-inch versions are:
- 574050A — ¾" FNPT
- 574056A — ¾" Press
Caleffi specifies a DZR low-lead brass body, a maximum operating pressure of 150 psi, and a maximum fluid temperature of 150°F, with an integrated discharge air gap.
Key Specifications
| Specification | Details |
|---|---|
| Brand | Caleffi |
| Part Number (MPN) | NA11605 |
| Product Type | Complete repair / rebuild kit |
| Compatible Series | 574 FlowShield™ RP |
| Size | ¾" |
| Compatible Models | 574050A / 574056A |
| Application | Reduced-pressure backflow preventer |
| Maximum Pressure | 150 PSI |
| Maximum Temperature | 150°F |
| Kit Weight | Approx. 0.8 lb |
| UPC | 8016615678505 |
Pressure and temperature limits reflect Caleffi's current catalog specifications for the 574 FlowShield RP series.
Low-Lead Construction and Certified Protection
The Caleffi 574 FlowShield RP is manufactured with DZR low-lead brass and is certified/listed to standards including ASSE 1013 and CSA B64.4. Caleffi also lists compliance with NSF/ANSI/CAN 61 and NSF/ANSI/CAN 372 for applicable products.
Those listings matter on potable-water work, where cross-connection control and material requirements both have to be satisfied — and where an inspector may ask which parts went into the rebuild.
NA11605 vs. Other 574 Repair Kits
Caleffi's rebuild kits are size-specific across the 574 FlowShield family, so the kit has to match the assembly:
| Caleffi Kit | Application |
|---|---|
| NA11604 | ½" 574 |
| NA11605 | ¾" 574 |
| NA11606 | 1" 574 |
| NA11607 | 1¼" 574 |
| NA11608 | 1½" 574 |
| NA11609 | 2" 574 |
Confirm the size stamped on the assembly before ordering — the kits are not interchangeable across sizes.
Who Uses the Caleffi NA11605?
The kit is a sensible stock item for anyone maintaining ¾-inch 574 assemblies on a testing schedule:
- Plumbing contractors
- Commercial plumbing maintenance teams
- Building and facility maintenance departments
- Hydronic and plumbing professionals
- Backflow prevention technicians
- Water-system service contractors
For crews already servicing a ¾-inch 574 FlowShield RP, keeping an NA11605 on the truck turns a failed annual test into a same-visit repair.
Why Buy from KPaul Industrial?
KPaul Industrial supplies contractors and facility maintenance teams with genuine replacement parts, valves, and industrial-grade components built for dependable service work.
Customers benefit from:
- Genuine Caleffi replacement components
- Competitive contractor pricing
- Fast product availability
- Support for plumbing, hydronic, and backflow applications
- Assistance with RFQs, bulk orders, and recurring purchasing
Final Takeaway
The Caleffi NA11605 is the purpose-built service kit for the ¾-inch 574 FlowShield™ RP. By combining the check-valve, discharge-valve, and seat components into one part number, it gives contractors a straightforward way to rebuild an existing assembly and return it to service — rather than replacing a valve body that still has plenty of life in it.
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