2026 Washington DC 1st Class Boiler Exam Prep Test

Feedwater is the water that is fed into a boiler to replace the steam that leaves the system. This water is typically preheated and treated because warming it before it enters the boiler reduces the energy needed to convert it to steam and minimizes thermal stress on boiler tubes. Treatment also removes or neutralizes minerals and gases that would cause corrosion, scaling, or fouling, helping maintain heat transfer efficiency and extend equipment life. Condensate returned from the system is part of feedwater in practice, but it isn’t simply returned unchanged; it is often blended with makeup water and conditioned to the correct chemistry and temperature before reentering the boiler. The steam produced by the boiler is not feedwater, and air used for combustion isn’t feedwater either.