In this month’s column, we will cover steam trap maintenance for low-pressure heating systems. These steam traps are typically found in schools, apartment houses, churches, and light commercial buildings. There are certainly some very large homes with steam traps as well.

We will start with the purpose of the steam trap. The low-pressure steam boiler receives a call for heat and the burner fires. After a short period of time, the water in the boiler begins to boil and changes state from water to steam. Once this occurs, steam begins to fill the steam mains in the building. Inside the mains, the air is being pushed through the pipe by the steam pressure behind it. At the same time, some of the steam condenses inside the relatively cold piping and drools towards the end of the mains. Something must allow the air and condensate to escape, this is where the steam traps (float and thermostatic in most cases) at the end of the mains come in.