What does AHU-X10 mean?
The hot-water supply temperature is too high for the current outdoor temperature — the reset schedule isn't being followed.
Why does it matter?
Every 10°F of unnecessary HW supply increases distribution losses, can prevent condensing operation on a condensing boiler (a 10-point efficiency hit), and wastes fuel maintaining hotter water that nobody needs.
What should you do?
Verify the OAT reset schedule is enabled. Check the OAT sensor accuracy. Confirm the worst-case zone really needs the high supply temp — most buildings can run 20–40°F lower in shoulder seasons.
How Energy Agent prices a finding
Written by Pelorus Engineering · Brent Waluzak, P.E. (FL), President, Pelorus EngineeringLast updated