What causes boilers to be taken out of service prematurely?
Most anyone experienced in steam and boiler maintenance will say "thinning of the plates" or "crown sheet." It all gets down to metal loss of pressure parts that are costly to repair or replace. Let's simplify some factors that are inter-related and all contribute to killing boilers. Using this information, you'll be able to save your boilers and be able to extend their life.
It is in perfect contact with the steel to "host" the chemical reactions we call rusting and corrosion.
Yes, we need it to breathe and burn fuels. It also pits and rusts iron. Water has both the oxygen that is used to make the water plus, extra dissolved oxygen that comes from the air. This extra dissolved oxygen is the boiler killer.