Heating System Water & Corrosion Prevention
All I see these days in trade magazine and merchants is magnetic filters, chemicals, chemicals and some more chemicals, every page you turn in a trade magazine has either an advert for magnetic filters or chemicals, or an article telling you how important inhibitors are to the system, well I say “utter nonsense”
Lets set some facts, todays heating systems are sealed, this means they are sealed from outside influences, including oxygen, now for corrosion to occur oxygen must be present, No oxygen = No Corrosion, so why do we need inhibitors, well in my opinion, we don’t, inhibitors create a false layer on the metal components, well in the presence of water metals will create their own natural layer to protect themselves, this is called passivation of the metal,The passivation of metals is the process, when metals protect themselves against further corrosion with a thin oxide layer. The metal becomes passive and is not oxidised any further.
The problems occur with poor design and the use of poor quality materials, inhibitors and magnetic filters are in my opinion there to cover for poor quality installations, whereas we should be looking to increase knowledge and standards, also I have been to many systems that have inhibitor that are still corroding.
Lets look at other points that need to be monitored in a heating system, but are generally ignored, The pH of the heating water should be in a range of 8.2 to 10, but only 8.2 to 8.5 in presence of aluminium alloys. The function of the pH in heating systems is one of the most important factors for means of corrosion protection. with the recommended pH range the metals in the system can basically build up their natural oxide layers and keep them stable to be protected against further corrosion. As long as this mechanism is not disturbed for example incorrect pH, a high electrical conductivity, a high oxygen concentration or erosion, the formation of natural oxide layers provides a safe protection of the metals against further corrosion