What does AHU-FC03 mean?
MAT is hotter than both the outdoor air and the return air — physically impossible without a fault.
Why does it matter?
Usually a MAT sensor in a heating-coil discharge stream or sun-loaded duct section. Misreads the mix temperature high, causing SAT control to under-call cooling.
What should you do?
Same as FC02 — inspect sensor placement and calibration. Check for duct radiant loading from adjacent hot surfaces.
This is a diagnostic rule: Energy Agent surfaces and ranks it as a data quality problem and claims no dollar savings for it, by design.
How Energy Agent prices a finding
Written by Pelorus Engineering · Brent Waluzak, P.E. (FL), President, Pelorus EngineeringLast updated