Navien NPE Installation & Operation Manual page 78

Outlet Flow Data
At altitudes above 2,000 ft (610m), the outlet flow will be reduced by 4% for each 1,000 ft (305 m) of altitude gain.
Note
78 Appendixes
[NPE-240S]
[NPE-210S]
[NPE-180S]
[NPE-150S]