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The 2" - 4" First Check Valve Assembly can be used on the Deringer 40 (RP) & 50 (RPDA-II) models or the Magnum 40 (RP) model and are for sizes 2", 2 ½", 3" and 4" and comes pre-assembled from the factory ready for installation.

The 2" - 4" First Check Valve Assembly includes:
  • First Check Valve Assembly
  • Cover Seal O-Ring
  • Retainer Bolt O-Rings

Note: This check valve assembly is for the 2" - 4" Deringer 40/50 and 2" - 4" Magnum 40 models only. The first and second check valves are not interchangeable.

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True-Seal™   Check Modules

The True Seal Check Valve was designed to incorporate a poppet only motion during the check stroke and is used exclusively on the first check assembly on the Deringer RP and RPDA models and Magnum RP model. This design allows a more consistent pressure loss across the check valve which helps maintain a steady and continual closure of the Relief Valve.

  • Light weight engineered polymer components
  • Modular for easy removal of complete check from body
  • Easily disconnect spring tension for safe check servicing
  • Replaceable Silicone Rubber Elastomer Disk
  • Excellent resistance to fouling.
Deringer & Magnum 40/50 First Check Skewed
Deringer & magnum 40/50 Low Flow Poppet Action

Poppet Action


  • 100% of check stroke is that of a poppet check
  • Consistent static sealing
  • Excellent resistant to fouling
  • Reliable check closure
  • Stable flow characteristics at ALL flow rates



Deringer Magnum First Check

First Check Maintenance

The First Check Maintenance Video provides a step by step procedure for maintaining a 2" - 4" Deringer 40/50 & Magnum 40 backflow preventers first check.

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Backflow Direct Product Warranty

Product Warranty

This printable document provides information for the Backflow Direct one year warranty for Deringer and Magnum backflow preventers.

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