Why heating water is cleaned and protected, and the steps that keep a system healthy.
The water in a sealed heating system circulates for years, so keeping it clean and treated protects the boiler, the pump and the radiators. Use this as a revision checklist of why and how, then follow the product and manufacturer instructions.
- Understand the enemy. Inside an untreated system, oxygen and dissimilar metals drive corrosion, which produces a black iron-oxide sludge that collects in radiators and the boiler and harms efficiency.
- Flush before dosing. Clean the system out first, because adding inhibitor to a dirty system just protects the dirt. New systems are flushed of installation debris; older systems may need a more thorough cleanse.
- Add inhibitor. Dose the system with a corrosion inhibitor at the correct concentration so the protective chemistry can work throughout the system.
- Fit and maintain a filter. An in-line magnetic and debris filter captures circulating sludge and metal particles, protecting the boiler and making future maintenance easier; it needs periodic cleaning.
- Check the inhibitor over time. Inhibitor depletes, so it is checked and topped up during servicing and after any work that drained the system.
- Mind the make-up water. Repeated topping up introduces fresh oxygen, so persistent pressure loss should be investigated rather than just refilled.
Clean water, the right inhibitor and a filter keep a heating system efficient and long-lived, which also supports the efficiency expectations in current guidance. Confirm products, doses and procedures against the manufacturer instructions.