New Video: How to make your steam boiler last forever

ethicalpaul

Hot water systems are "closed" because there is no exposure to the atmosphere in their normal operation. These air separator devices are good for those systems because they allow the oxygen that is in the water to separate and then be removed. You want to keep air out of a closed hot water system because it can cause bad things like preventing the water from circulating. This is my best understanding, someone will correct me if I'm wrong.

A residential steam system is "open" because every time a call for heat ends, when the steam condenses to liquid water (at 1/1700 its former volume), all the space in the pipes and boiler is then filled with regular air which is then in contact with the boiler water.

seized123

@ethicalpaul I get it, wow, that's a lot of air in the system. But, then, how can getting a few oxygen bubbles out of the water you put into the boiler, by preheating it, or whatever, make a difference when every cycle the system gets inundated by air?

ethicalpaul

It's a great question. The answer is that even though water may be sitting in a room full of air, the air doesn't just race to get in the water solution. This is why you have to have an aerator on a tropical fish tank.

The water that gets freshly added to a boiler, with its added oxygen, is going to release all that oxygen into the boiler and I believe that is where a lot of corrosion occurs.

This is why a boiler in a steam system without leaks can last years longer than a system with leaks where fresh water is being added more often, even though both are the same "open" systems.