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The Deringer & Magnum 40/50 Relief Valve is the smallest and the lightest relief valve assembly in the industry. The Relief Valve is all stainless steel and only has two exit ports to reduce spray pattern along with a Stainless steel braided sensing line.

The Relief Valve Assembly includes:
  • Stainless Steel Investment Cast Body
  • Stainless Steel Piston
  • Frictionless Rolling Diaphram
  • Braided Stainless Steel Sensing Line

Note: This relief valve assembly fits all valve sizes (2" - 8")



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Relief  Valve

Relief Valve Image

Guide Bearing

Deringer & Magnum Guide Bearing

The Deringer & Magnum 40/50 Relief Valve uses a stainless steel body, piston seal and stainless steel sensing line and has been designed to be the smallest and lightest Relief Valve in the industry.

Unlike previous relief valve designs, the piston seal does not use the body of the relief valve to align itself properly when closing and opening and instead uses the guide pin on the piston. This will aid in making the Relief Valve resistant to build up and binding.

All components of the relief valve are lead free and meet the SDWA requirements.

 Maximum Relief Valve   Discharge Rates

Deringer and Magnum Reduce Pressure Relief Valve Discharge Rates

Air Gap Assembly will capture and evacuate light water discharge from the Relief Valve caused by daily fluctuation in system/supply pressure. An Air Gap Assembly will NOT capture and evacuate the Maximum Relief Valve Discharge Rate caused by catastrophic valve or system failure. An auxiliary drain (separate and independent of the Air Gap Assembly) is REQUIRED and MUST be properly sized for the Maximum Relief Valve Discharge Rate. Backflow Direct shall not be responsible for any special, consequential or incidental damages, including without limitation, repair costs, lost profits, property damage, or any other costs resulting from labor charges, delays, vandalism, negligence, fouling caused by foreign material, adverse water conditions or any other circumstances, caused by lack of auxiliary drain, location of auxiliary drain or undersized auxiliary drain.



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Relief Valve  Maintanence

The Relief Valve Maintenance Video provides a step by step procedure for maintaining a Relief Valve for a 2" - 8" Deringer & Magnum 40 & 50 backflow preventer.

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Relief Valve Discharge Rates

This is a printable version of the relief valve discharge rates for Deringer and Magnum backflow preventors as well as information on the air gap assembly.

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Backflow Direct Product Warranty

Product  Warranty

This is a printable version of the backflow direct one year warranty.

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