What is the main benefit of converting older 2 pipe gravity systems to pumped return?

The main benefit of converting older two-pipe gravity systems to pumped return is the positive condensate return to the boiler. In a gravity system, condensate relies on gravity to return to the boiler, which can lead to issues such as condensate pooling or being unable to effectively return to the boiler due to elevation changes or inadequate slope in the piping.

By implementing a pumped return system, condensate is actively pushed back to the boiler, ensuring a more efficient and reliable return of water. This can improve the overall efficiency of the heating system, reduce the risk of water hammer, and maintain better boiler operation by ensuring that the condensate is consistently available for reuse in the steam generation process.

As a result, this conversion enhances the functionality and performance of the heating system, allowing for fewer operational issues and improved energy efficiency. The other options do not address the primary issue of condensate management and system reliability, and therefore do not provide the same benefit in the context of a pumped return system.