What type of valve must hot water boilers be protected with?

Hot water boilers must be protected with a pressure relief valve to ensure safe operation. This type of valve is crucial because it helps prevent excess pressure accumulation within the boiler system, which can lead to dangerous conditions, including potential boiler explosions.

In essence, the pressure relief valve is designed to automatically open and release steam or water when the pressure exceeds a certain threshold, thereby maintaining safe operating levels. This is particularly important in hot water boilers, where increasing temperatures can lead to rising pressure levels.

While other types of valves serve important functions—such as managing flow, isolating different sections of a plumbing system, or regulating temperature—they do not provide the same level of safety against overpressure situations that a pressure relief valve does. Thus, ensuring that hot water boilers are equipped with a properly functioning pressure relief valve is a critical safety measure in any heating system.