Two-pipe medium- and high-pressure systems (with ranges of 25 to 125 psi) are used for space heating and for steam-process equipment such as water heaters, dryers, kettles, etc. The two-pipe high-pressure steam-heating system is used for space heating and employs tube radiation, fin vector radiation, unit heaters, and fan units having blast coils. High-pressure thermostatic traps or inverted bucket traps are generally used in this type of installation to handle the condensate and to vent the air in the system.
Advantages of two-pipe medium- and high-pressure steam-heating systems include:
1. Since the return water can be lifted into the return mains, condensate-return lines can be elevated.
2. High-pressure or boiler-feed condensate pumps return the condensate directly to the boiler.
3. Smaller radiators or heat-exchange units and smaller pipe sizes may be used.
4. If the system is used for both heating and steam processing, a simplified piping system may be used with the supply mains being used for both the heating and processing equipment. A common
condensate system may be installed.
