Water Treatment Hydronic (Hot Water Boilers)
Hot water boilers (non-steam systems) have minimal water treatment requirements. Typically the only additive is a small amount of corrosion inhibitor and perhaps some glycol (antifreeze) if the system could be exposed to freezing temperatures. Common water treatments are similar to those used in automotive cooling systems.
Blowdown is not done with hot water systems and make-up water is typically minimal. (Unless there is a prolonged system leak.)