InterNACHI Heating, Ventilation, and Air Conditioning (HVAC) Practice Exam

A boiler can indeed operate without a pressure-reducing valve, depending on the design and application of the boiler system. In certain configurations, especially in smaller, more straightforward systems or older designs, the boiler might rely on other mechanisms or components to manage system pressure.

For instance, if a boiler is designed to operate at the same pressure as the incoming supply line, it may function effectively without the precision regulation that a pressure-reducing valve provides. In these cases, the water pressure from the supply can be sufficient for the boiler to function correctly, allowing it to produce steam or hot water as needed.

However, it is essential to note that the absence of a pressure-reducing valve can lead to issues in systems where precise pressure control is necessary for optimal performance and safety. In modern systems, pressure-reducing valves are typically included to maintain safe operating conditions and to protect boiler components from excessive pressure.