What type of water should not be used in a boiler?

Using sea water or high mineral content water in a boiler can lead to significant operational issues. Such water typically contains high levels of salts and minerals, which can cause scaling and corrosion within the boiler system. This scaling can build up on the heating surfaces, reducing efficiency by obstructing heat transfer and potentially leading to overheating and failure. The increased mineral content can also lead to foaming, which can carry water into the steam lines, resulting in water hammer and other operational problems.

In contrast, distilled water is ideal for use in boilers because it is free from minerals and impurities that could affect system performance. Tap water generally contains dissolved minerals and chemicals, which can lead to similar issues as sea water, though the level of risk can vary based on water quality. Rainwater, while potentially low in mineral content, can also vary in quality and may pick up contaminants during collection.

Overall, for consistent boiler operation and longevity, it is crucial to use water that is free from excessive minerals and impurities, making high mineral content water unsuitable.