SENTRY GS Excess Flow Valves


Excess Flow Valves

SENTRY GS Excess Flow Valves

SENTRY GS are designed to close, shutting off the gas flow, when a prede­fined flow rate is reached. Gas utilities use excess flow valves (EFV) to minimize the risk of damage in the case of a break in the gas line. SENTRY GS have been used success­fully and effec­tively for more than 25 years in under­ground gas service lines and residential instal­la­tions throughout the world. In Germany alone, more than 1,000,000 Maxitrol excess flow valves are currently in service.

Maxitrol EFVs are calibrated at the factory, providing a precise and reliable closing flow rate. In the nominal flow range, the EFV remains in a stable, open position. If equipped with a bypass, SENTRY GS reopen after the downstream line has been repaired and re-pressurized.





  • Nominal sizes from DN15 to DN50 (d20 to d63)
  • Operating pressure ranges from 1,5 to 500 kPa
  • Factory-tested both individ­ually and as a complete unit
  • No synthetic materials used for compo­nents trans­mitting energy
  • Maximum closing flow rate of 1.45 times the nominal flow rate
  • Narrow tolerance calibrated by-pass orifice to ensure a quick reopening
  • Low pressure drop
  • Patented damping system to greatly reduce the number of nuisance shut-offs

SENTRY GS for Residential Installation

Excess flow valves for in-house gas instal­la­tions are installed downstream of the main gas manual shut-off valve (ECV). SENTRY GS are also available in combi­nation with a thermally activated cut-off device SENTRY GT, that shuts off the gas flow at 92 °C to 100 °C.

🇦🇺 NEW for Australia and New Zealand

This SENTRY GS EFV is installed downstream of the regulator and prior to any multi­layered pipe. SENTRY GS EFVs with bypass orifice reopen automat­i­cally after the downstream line has been repaired and re-pressurized.

Complies with the new AS/NZS5601.1 (Clause 5.2.11) Installation Codes (mandatory March 31, 2023 for Australia)

  • Operating pressure range: EU 1.5–10 kPa (AU/NZ 1.25–10 kPa)
  • SENTRY GS “Z” model is for horizontal and upward flow direction 
  • SENTRY GS “D” model is for downward flow direction only 
  • Threaded connec­tions comply with EN 10226–1 (ISO 7–1) from ½” to 2″ (DN 15–50) 
  • BS 746 connec­tions available 
  • Nominal flows from 1.6 m3/h natural gas to 16 m3/h 
  • Closing factor of type “K” is between 1.3 and 1.45. The trip flow is 30–45 % above nominal flow. 
    (In Germany only this type of EFV can be used with composite pipe or PEX pipe. It is the type “K” per defin­ition in the standard DIN 30652–1.)
  • Maxitrol patented damper function (DN 15 — 25) can avoid a nuisance shut-off in case of flow peaks. 

Free Sizing Software

As a special service, Maxitrol offers free software for selecting the correct excess flow valve and calcu­lating the pipe sizes. This program is currently available only in German language. Request your free program here.

Sizing Software for SENTRY GS

SENTRY GS for Gas Service Lines

Excess flow valves are preferably installed in the branch line off the main gas line and in the gas service line. The SENTRY GS for under­ground service lines can be special ordered to fit customer-specific instal­lation require­ments. We can supply the EFVs in electro­fusion couplers and reducers. SENTRY GS are easily traced with a barcode (optional) on the fitting. An ID-Card, showing the product infor­mation is delivered with the standard SENTRY GS.

Sentry GS Excess Flow Valves; Residential

Literature; Excess flow valves for residential installations.

🇬🇧 GSH-LT-EN-02.2019 DownloadPreview
Sentry GS Excess Flow Valves; Service Lines

Literature; Excess flow valves for gas service lines.

🇬🇧 GSE-LT-EN-02.2022 DownloadPreview
Sentry GS Excess Flow Valves; Sentry GT Thermal Cutoff Devices

Thermal cut-off devices for legacy installations & excess flow valves for the UK.

🇬🇧 UK, GSH.GT-LT-EN-02.2023-UK DownloadPreview