If you want to catch mice the simple solution is to use a mouse trap. If the mouse trap does not work, and often they don't, then you have to find an alternate solution. One good solution is to get a natural predator of the mouse to assist. The house cat is about as effective a mouse eradication tool known to man and they will accomplish the job. A simple solution for a simple problem.
Don’t Get Steamed
The same goes if you're going to try to trap steam, you find the most effective way to accomplish this, and what is the tool to use? It's known as a steam trap. Now you may be asking, what does a steam trap do? To answer that question, we have to examine what are the different types of steam heating systems? There are two general types of low pressure steam heating systems—there are one pipe systems and two pipe systems. In a one pipe steam system, steam and condensate share the same pipe to the radiator. In a two pipe steam system, the steam enters the radiator through one pipe and condensate leaves through another pipe at the opposite end of the radiator. That is what we mean by the term—two pipe steam heating.
The problem then is the following: How do you prevent steam from leaving the radiator so it does not get into the condensate return system? There are various ways of solving this problem. The most commonly used technique is to put a “steam trap” at the end of the radiator.
A steam trap is a mechanical device that has to do two things: It has to allow the condensate to leave a radiator while at the same time preventing steam from getting into the condensate return lines. The type of trap used for this purpose is a thermostatic trap. There are also float and thermostatic traps on the ends of the main steam lines. These traps are designed to handle the larger amounts of condensate which forms in the main steam lines in basements and cellars of residential buildings.