Project required demo and disposal of all existing failed preheat systems; which included piping, controls, coils and components for AHU’s 8A, 8B, 8C, 9, 10, 11 located in the 3rd floor roof penthouses. Provided and installed new high pressure steam service from B2 tunnel level to the penthouses and converted entire heating water preheat system to steam. Provided and installed new steam stations, coils, piping, condensate receivers, expansion loops, DDC controls, frequency drives and fan repairs for all units. All work was required to be completed in a 10 week period. Combined systems load requirements were more than 300,000 CFM of conditioned outside air. All work was completed while systems were running and building was fully occupied.