Which of the following is a requirement for a good boiler?

A good boiler must be responsive to demands, which means it needs to adjust its operation efficiently based on the heating requirements of the system it serves. This responsiveness allows the boiler to provide the necessary heat output while optimizing fuel consumption and reducing waste. In practical scenarios, a boiler operating efficiently can quickly increase or decrease its output, maintaining a stable temperature and ensuring comfort or process requirements are met.

Understanding the demands of a system helps ensure that a boiler can cater to both peak and off-peak loads, providing energy efficiency and reliability. This capability is crucial for both residential and industrial applications, where fluctuating heat demands are common.

The other aspects such as complexity, manual operation, or high costs are not intrinsic requirements for a good boiler. A boiler that is overly complex may lead to more maintenance issues, while manual operation can hinder efficiency and responsiveness. High initial costs do not guarantee performance; rather, a boiler's ability to effectively respond to varying needs is what defines its quality and effectiveness.