What is the effect of not having a feedwater pump on the safety relief valve setting?

In a boiler system, the feedwater pump is essential for maintaining appropriate pressure levels within the boiler. If a feedwater pump is not present or malfunctioning, there may be inadequate pressure to maintain the water level in the boiler. This can lead to a situation where the safety relief valve may need to be set lower than normal to ensure it can effectively release pressure and prevent the boiler from exceeding its safe operating conditions.

When the water level is low due to insufficient feedwater supply, the risk of overheating and eventual boiler failure increases. Therefore, setting the safety relief valve lower acts as a precaution to protect the boiler from potential excess pressure that could arise from inadequate cooling and steam generation. This adjustment helps to ensure that the boiler operates safely under these compromised conditions, as it would relieve pressure more readily to avoid dangerous situations.

The other choices do not align with the fundamental relationship between the pump's operation and the safe pressure limits of the boiler.