What type of water should be avoided in hydronic systems?

In hydronic systems, hard water should be avoided due to its high mineral content, particularly calcium and magnesium, which can lead to scale buildup within pipes, heat exchangers, and other components of the system. This scale accumulation can severely hinder the efficiency of heat transfer, cause clogs, and ultimately lead to equipment failure.

Soft water, deionized water, and distilled water, on the other hand, have significantly lower mineral content. Soft water has exchanged minerals that could cause hardness, deionized water has had most ions removed, and distilled water is free from most impurities. Therefore, these types of water are generally safer for use in hydronic systems because they minimize the risk of scaling and related maintenance issues, promoting the longevity and efficiency of the system.