On which side of the shut-off valve shall a relief or pressure regulating valve be provided?

A relief or pressure regulating valve is installed on the heater side of the shut-off valve to ensure proper safety and functionality. The purpose of this valve is to manage and limit the pressure that can build up within the system, preventing potential hazards such as overpressure which could lead to equipment failure or accidents.

Having the valve positioned on the heater side allows it to effectively monitor and release excess pressure before it can cause damage to the heating system. This setup is crucial because it protects the equipment connected to the heater and maintains safe operational conditions. It’s also important to note that placing it on the burner or discharge side may not provide the necessary protection to the heating element, risking safety and operational integrity.