Masoneilan 174 Series

The Masoneilan 174 Series regulators are a spring loaded, direct operated regulator for pressure reducing or relief applications in a variety of industrial applications. The large diaphragm area provides more accurate control at low pressure settings and the lever design provides excellent shut-off tightness. These regulators are available in ½” up to 1½” (DN15 through DN40) body sizes with a maximum inlet pressure of 145 psig (10 barg). The simple construction makes it very flexible, easy to install and to maintain.

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General features:

  • Flow to open or close design (depending on function)
  • Internal pressure sensing
  • Resilient single seat
  • Elastomeric Diaphragm
  • Flexible body orientation to simplify installation
  • Spring Loaded, Direct-Operated Regulator for Pressure Reducing or Relief Applications



174-1 Pressure reducing

174-7 Back-Pressure / Pressure Relief


Gas, Air


½” through 1-1/2” (DN15 through DN40


Connections: Screwed (NPT)


Maximum Inlet Pressure

174-1 Reducing: 145 psig (10 barg)

174-7 Relief: 4.4 psig (0.3 barg)
Maximum Outlet Pressure

174-1 Reducing: 8.8 psig (0.61 barg)

Set Pressure Range:

174-1 Reducing: 1.4 inches w.c. to 8.8 psig

174-7 Relief: 1.4 inches w.c. to 4.4 psig

Temperature Range:

-0.4° to 194°F (-18° to 90°C)