A system for managing drainage of heat pump coil condensate using a building's legacy heat piping infrastructure. The system includes a drainage pan that accumulates condensate and directs it into condensate piping. The condensate piping feeds the condensate into the building's legacy heat piping infrastructure, preferably after treating the condensate with a neutralizer to reduce its acidity. The system also includes a system control for monitoring the accumulated condensate levels and the status of the legacy heating system to determine when to open a flow control means allowing the condensate to drain from the condensate piping into the building's legacy heat piping infrastructure.