A nitrogen sweep stream for use in a deaerator during deaerator operations to disperse and remove oxygen and carbon dioxide from boiler feed water prior to being fed to a boiler. The nitrogen sweep stream substantially reduces the amount of oxygen and carbon dioxide in the water supply system. The water supply system can be sent to a deaerator stripper or can be heated using a heat exchanger. A heat water supply stream can also be sent directly to the deaerator water tank. The nitrogen sweep stream reduces the amount of oxygen contained with the boiler feed water stream to less than 7 ppb and reduces the amount of carbon dioxide to nondetectable levels. The nitrogen sweep may be provided to an existing deaerator, not having been previously provided with a nitrogen sweep, while the deaerator is running without shutting down the deaerator.