What does AHU-FC05 mean?
Heating valve is open but SAT isn't rising above MAT by more than the fan-heat tolerance — the heating coil isn't delivering heat.
Why does it matter?
Lost heating capacity. Either the coil is air-bound, hot-water flow isn't reaching it, or the valve is reporting open but mechanically stuck closed.
What should you do?
Check HW supply temperature at the coil inlet. Bleed the coil for air. Verify HW pump is on and the isolation valve is open. Inspect the heating valve actuator linkage.
How Energy Agent prices a finding
Written by Pelorus Engineering · Brent Waluzak, P.E. (FL), President, Pelorus EngineeringLast updated