Excess Flow Valves

Excess Flow Valves are an additional feature to be used in combination with bursting discs to protect a refrigeration system from overpressure.

The use of excess flow valves is recommended in accordance with fact sheet AD2000 A1 and ASME Boiler & Pressure Vessel Code VIII Div.1 (paragraphs UG 125 through UG 137) when bursting discs or relief valves are being used in series or in combination. Excess flow valves keep the space between safety valve and bursting disc pressureless in case smaller leaks occur. They prevent the build-up of counter pressure. They work with a ball that gets pushed into its seat, if an overpressure occurs, e. g. when the bursting disc opens, thus preventing ventilation and enabling the safety valves to perform as intended. Furthermore pressure manometers and controllers can be connected.

Technial Features

  • Available in stainless steel
  • Selection of body material as per German DIN EN12284, AD2000 Series W
  • Working mediums: refrigerants as per EN 378 p. 1, e. g. NH3, R22, R134a; gaseous mediums
  • Use of bursting discs is not permitted in a system where the maximum operating pressure is higher than 90% of the low bursting tolerance. Bursting discs are suitable for gases, but not liquids. The burst tolerance is +/- 10% or optionally +/-5%.

Excess Flow Valves


stainless steel

Nominal Size

 appropriate for bursting discs DN 15-100

Nominal Pressure Level

DN15-25: PS 25, 40, 63

DN 32-100: PS 40

Temperature Range for Standard Valves

-60 °C to +150 °C

Temperature Range for HT Valve Series

-10 °C to +200 °C


to be connected to the bursting disc holder via a G1/4″ or NPT1/4″ thread

Get in touch

Armaturenstr. 2
17291 Prenzlau

Phone: +49 3984 8559-0
Fax: +49 3984 8559-18