Steam boilers were in for a big change when the price of energy skyrocketed in the 1970s and efficiency standards were mandated. When steam is used as a form of energy it’s best to think of it as a gas (which it is). It is invisible and contains no more than 2% water, best if less than 1%. It’s nothing like the wet steam that rises off your stock pot when making pasta or from your tea kettle. That steam is wet, and no good for energy production. Before the 1970’s steam boilers used an internal steam chest to separate the water from the steam. Those old boilers were quite large as a result. When the efficiency mandates appeared, boilers had to get a lot more efficient, and to do that, they had to get smaller. For steam boilers that meant the steam chest had to go. But then how to get the water out of the steam if we remove the steam chest? Once again, clever men went to work and a solution was devised. It was found that by carefully designing the near-boiler piping coming out of the boiler, that this piping arrangement could do the same job as the old steam chest in separating the moisture from the steam. It was a great victory for the boiler manufactures. Not only could they make boilers that met the efficiency mandates, but they could also off-load the cost of the steam/water separation process to the contractor or plumber who was to install the boiler!

You can guess what the tradesmen thought of this arrangement. Not much. So lesser boiler manufacturers began to skimp on their piping requirements for their boilers and this naturally brought them more business from contractors. The homeowner suffered because of the loss of efficiency inherent in wet steam, but for the most part they were in the dark so complaints were few and far between. As usual, people just blamed it on the steam itself…

Today, sad to say, far too many steam boilers are installed with incorrect near-boiler piping. This results in the boiler producing wet steam, which is very inefficient and is often the main culprit in high energy bills. It can also lead to banging and other disconcerting problems