All steam and hot water boilers are required to have a pressure relief valve. What is one condition that is NOT required for installation?

The correct option pertains to the condition for pressure relief valve installation in steam and hot water boilers. The requirement that a discharge pipe shall drain into a sump tank is not standard practice. In fact, pressure relief valves are typically designed to discharge steam or hot water to the atmosphere or into a safe drainage path, rather than into a sump tank. This allows for the dissipation of pressure and prevents the accumulation of potentially hazardous steam or water.

The other conditions listed are crucial for the safe and effective operation of the pressure relief valve. Ensuring that the valve is installed in a vertical position is important for the proper functioning of the valve, allowing it to operate correctly when pressure relief is needed. Furthermore, having pipe supports within a set distance helps maintain the integrity of the piping system and ensures that the discharge pipe is secure and can withstand the operational pressures. The requirement for the discharge pipe to be of equal diameter is established to prevent bottlenecks, ensuring that the flow can be released efficiently and rapidly in case of pressure build-up.

Each of these requirements is designed to ensure safety and efficacy, highlighting the critical role of proper installation and maintenance of pressure relief valves in boiler systems.