ISO 23551-8:2023

This document specifies safety, construction, performance and testing requirements of multifunctional controls (MFC) intended for use with gas burners, gas appliances and appliances of similar use.
This document applies to an MFC with declared maximum inlet pressures up to and including 50 kPa (500 mbar) of nominal connection sizes up to and including DN 150 for use on burners or in appliances using gases such as natural gas, manufactured gas or liquefied petroleum gas (LPG). It is not applicable to corrosive and waste gases.
An MFC consists of two or more functions, at least one of which is a mechanical control, as specified in the relevant control standards.
This document is also applicable to construction and performance requirements for components of burner ignition systems as specified in Annex K. The requirements and test methods in Annex K include optional type testing and evaluation of these components.
This document is applicable to:
—     water-operated gas valves (see Annex I);
—     overheating safety devices (OSDs) (see Annex J); and
—     optional requirements for components of burner control systems (see Annex K).