M Series

Small connection (1/4" to 1/2" or DN 8 to DN 15) pressure relief valves.


Griffco M-Series diaphragm pressure relief valves are designed to protect chemical feed systems overpressure damage caused by defective equipment or a blockage in the chemical feed line. Robust construction ensures reliability in the rigorous service of municipal and industrial applications.

Wetted Materials: PVC, CPVC, PP, PVDF, PTFE, Halar®, 316 SS, Alloy 20, Hastelloy® C

Available Sizes: 1/4″ to 1/2″ or DN 8 to DN 15

Features & Benefits:

  • High reliability at a low cost
  • 2-port, 3-port, and 90° configurations
  • Solid, robust, machined construction
  • Wide range of materials
  • Union, threaded and socket connection options
  • Molded Noryl top with integral hardware locking
  • 316L metal valve and top options
  • Molded PTFE/EPDM diaphragm
  • Multiple diaphragm material options
  • Long diaphragm life
  • Adjustable up to 350 psi (24 bar)
  • 4 optional pressure ratings (springs)
  • Valve sizes from 1/4″ to 1/2″ or DN 8 to DN 15
  • Tamper-resistant adjustment screw
  • High-temperature option up to 300°F (149°C)
  • Factory or field settable

Griffco M Series Pressure Relief Valve
Model NumberMfg.Connection Size/TypeMaterial
PRM025AGriffco1/4" NPTAlloy 20
PRM025CGriffco1/4" NPTHastelloy C
PRM025CPGriffco1/4" NPTCPVC
PRM025KGriffco1/4" NPTPVDF
PRM025PGriffco1/4" NPTPVC
PRM025PPGriffco1/4" NPTPolypropylene
PRM025SGriffco1/4" NPT316 SS
PRM025TGriffco1/4" NPTPTFE
PRM038AGriffco3/8" NPTAlloy 20
PRM038CGriffco3/8" NPTHastelloy C
PRM038CPGriffco3/8" NPTCPVC
PRM038KGriffco3/8" NPTPVDF
PRM038PGriffco3/8" NPTPVC
PRM038PPGriffco3/8" NPTPolypropylene
PRM038PPBGriffco3/8" BSP ThreadsPolypropylene
PRM038SGriffco3/8" NPT316 SS
PRM038TGriffco3/8" NPTPTFE
PRM050AGriffco1/2" NPTAlloy 20
PRM050ASGriffco1/2" SocketAlloy 20
PRM050CGriffco1/2" NPTHastelloy C
PRM050CPGriffco1/2" NPTCPVC
PRM050CPSGriffco1/2" SocketCPVC
PRM050CSGriffco1/2" SocketHastelloy C
PRM050KGriffco1/2" NPTPVDF
PRM050KSGriffco1/2" SocketPVDF
PRM050PGriffco1/2" NPTPVC
PRM050PPGriffco1/2" NPTPolypropylene
PRM050PPSGriffco1/2" SocketPolypropylene
PRM050PSGriffco1/2" SocketPVC
PRM050SGriffco1/2" NPT316 SS
PRM050SSGriffco1/2" Socket316 SS
PRM050TGriffco1/2" NPTPTFE