Deep-set venting gauge hatch

  • The Series 4000 Marsh Hawk TRV offers tank access combined with pressure and vacuum relief in a deep-set design.
  • Situating valve seats below the tank roof permits latent heat from the product to keep the seals ice-free.
  • Now available with “Bottom Flange” connections suitable for direct-tank mounting in non-freezing applications.

Reliable, bubble-tight sealing

  • The Series 4000 has class-leading seal performance as compared to any other premium or economy venting gauge hatch currently available.
  • Improved sealing performance eliminates flutter and periodic small-scale venting which can cause frost closure in competitor top-mount hatches.

Variety of pressure settings

  • The Series 4000 Marsh Hawk pressure relief is adjustable between 2 ozsi and 16 ozsi in 2 ozsi increments.
  • The optional double-weight spring allows relief pressure between 18 and 32 ozsi, in 2 ozsi increments.
  • 1 ozsi increments optionally available.
  • Vacuum relief is fixed at 0.4 ozsi.

Suitable for Sour Service

  • The Series 4000 is ready for Sour Service out of the box with FKM (Viton) seals and stainless springs.
  • For more adverse applications, alternative seal and spring materials are available, along with hard anodization or fusion-bond epoxy coatings.



Function Venting Gauge Hatch
Temperature Range (FKM) - 26°C to 204°C [-15°F to 400°F]
Temperature Range (FEPM) -9°C to 230°C [16°F to 446°F]
Temperature Range (FFKM) -18°C to 320°C [0°F to 600°F]
Pressure Relief Type Direct-acting, Spring-loaded
Pressure Relief Range 2 to 32 ozsi
Vacuum Relief Range 0.4 ozsi fixed
Tank Connection 8” API (Fig 1 API 12F)

Related Documents


Download Brochure

Vent Sizing Chart

Download Vent Sizing Charts

A guide to venting upstream tanks

Download TB-1217-TV

Installation Instructions

Download Instructions

Mounting and Riser considerations

Download Mounting Guide

Coating Specifications

Download Coating Spec Sheet

Ordering Information

Standard Series 4000 Marsh Hawk configurations are stocked ready to ship. Other configurations are typically assemble-to-order and available in under two weeks.

  1. Specify Series 4000 Marsh Hawk TRV
  2. Specify Relief Setting
  3. Specifiy gasket materials, other options.

See part matrix on the brochure for more information.

Consider completing your Series 4000 Marsh Hawk Installation with a Riser, Bolt Kit and Tank Gasket.

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