Countywide Mechanical served as the prime contractor, direct to the City of Santee, to replace the aging HVAC equipment serving the City Hall complex. Composed of eight buildings, the design-build project included 43 rooftop packaged heat pumps ranging from 2.5 ton units to one 10-ton unit. With only 40 calendar days to complete the change out, while coordinating around an open and operating facility, with the additional requirement for a unit to be removed, replaced, and operating again within a 24-hour period, the project required complex phasing. Over 7 days spanning a month, a crane was used to remove the old equipment and lift the replacement equipment into place. Due to the limited lay down space available at the operating facility, just-in-time deliveries coincided with all crane days. A pro-lift was used on the roof to maneuver the units into place. In addition, all interior work, such as duct cleaning, had to be done after hours.