With winter coming up, it’s a good time to brush up on your knowledge of steam traps. There are steam traps on radiators, of course, but they’re actually used in a number of residential, commercial, and industrial applications. The only problem is that so much of the literature published on these little devices is incredibly technical and hard to decipher. Here’s an overview — sans technical jargon.

What Steam Traps Do

Steam traps are devices that contain steam while allowing condensate and non-condensable gasses to escape. The simplest example in practice is a basic steam radiator. When you first start a radiator system, there is air in the pipes. A steam trap allows this air to escape (that’s the hissing sound that’s so commonly heard when you first turn on the heat). But once the steam reaches the pipes, the steam trap keeps all the steam inside so it can transfer its heat to the fins of the radiator and warm your room. Steam traps work similarly in other applications, and can default to being either open or closed, depending on how the system is designed and how much steam pressure needs to be maintained.

How Steam Traps Work

How do steam traps accomplish that? There are several different designs, with the valve being activated mechanically, electronically, or thermally. With a thermostatic steam trap, for example, it’s the changing temperature that causes the steam trap to open or close (think of the heat rising as steam builds up in radiator pipes). But for other types of traps, rising levels of condensate might lift a float and activate the valve. In still other types of steam traps, varying pressure activates the mechanism.

What Steam Traps to Get

So if you’re in the market for steam traps, which ones should you buy? A the top of the line are Spirax Sarco steam traps (commonly referred to as Spirax steam traps). There are certainly other brands — and generics, too — but they won’t last as long or be as reliable. Fortunately, Spirax steam traps come in both professional and economy lines, so you can get something in your budget without going all the way down to no-name brands.

Do you have any other advice to share on buying, using, or maintaining steam traps? Join the discussion in the comments.