ISO 23551-9:2022

This document specifies safety, construction, performance and testing requirements for mechanical gas thermostat intended for use with gas burners and gas burning appliances hereafter referred to as “thermostats”. This document applies to mechanical gas thermostats of nominal connection sizes up to and including DN 50 with declared maximum inlet pressures up to and including 50 kPa, for use with natural gas, manufactured gas or liquefied petroleum gas (LPG). It is not applicable to corrosive and waste gases. This document applies to mechanical thermostats: —    controlling the gas flow directly or indirectly through an integral gas valve, and which do not require external electrical energy for their operation; —    used on gas appliances where the thermostat is not directly exposed to the outdoor environment; and —    which are intended for operating control functions. This document covers type testing only.