At or below what setting should the pressure relief valve be for hot water heater boilers?

The appropriate setting for the pressure relief valve on hot water heater boilers must be at or below the Maximum Allowable Working Pressure (MAWP) to ensure safe operation. The MAWP defines the maximum pressure that the boiler or pressure vessel is designed to withstand under normal operating conditions.

If the pressure relief valve is set above the MAWP, there is a risk that the boiler could be subject to pressures that exceed its design limits, which can lead to catastrophic failure or safety hazards. Setting the relief valve at the MAWP or lower provides a critical safety mechanism by allowing it to release excess pressure before the limits of the system are reached, thereby preventing overheating or pressure build-up that could potentially lead to an explosion or other hazardous situations.

This safety measure is a standard best practice in hydronic and process piping, ensuring compliance with engineering codes and promoting the safe operation of heating systems.