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Keedian operations · Standard procedure

AHU not holding discharge — supply air above setpoint under a cooling call.

The air handler holds its supply-air (discharge) temperature above the value its sequence commands while it is calling for cooling — it cannot make the air the floor was designed to receive. Because every box on the handler draws that supply air, one out-of-band AHU warms a whole floor at once: a fouled coil, a chilled-water valve losing authority, low coil flow, or a capacity shortfall at peak.

01 Detail

Trigger, action plan, and escalation criteria.

optimization_metric hvac high essential tier AI: hybrid
Related metric
ahu_supply_air_temp_compliance
Trigger
|supply_temp − commanded_setpoint| > tolerance AND cooling_call, sustained ≥ deviation_duration
Value drivers
Customer experience Asset lifespan
Preconditions
The supply-air setpoint and any reset schedule confirmed per AHU so compliance is scored against the commanded (reset-aware) target; the discharge sensor calibrated at onboarding so a deviation reflects the handler, not the sensor; the handler's design supply-air conditions recorded as the reference for in-band.
Human role
Scales by tier — at Essential the customer sees the handler out of band and adjusts the sequence themselves; at Managed, Keedian Ops triages the direction of the deviation and dispatches; at Optimized, Keedian commands the AHU sequence within authority (supply-air setpoint and reset, valve and fan). A mechanical fault — a fouled coil, a failed valve — is referred for a scoped service.
Action plan
(1) Confirm the target and the sensor before treating the deviation as real — a supply-air reset scored as a fixed setpoint manufactures deviations, and a drifted discharge sensor manufactures both false breaches and false compliance; validate both first. (2) Confirm the discharge holds above the commanded setpoint under an active cooling call for a sustained period, not a single interval or an economizer-only window. (3) Place the cause by direction and by the coil side: supply air riding above setpoint with the chilled-water valve driven full and a low Cooling ΔT points to a fouled coil or lost flow; a valve not opening to the call points to a valve or actuator fault; a shortfall only at peak points to capacity. (4) Tiered response: at Essential surface the out-of-band handler; at Managed triage and dispatch; at Optimized command the sequence (setpoint/reset, valve, fan) within authority, with an audit trail, and refer a fouled coil or a failed valve for a scoped service.
Escalation
(1) A handler that has lost its discharge on an occupied floor with zone temperatures already rising → direct action before floor-wide comfort loss, not the monthly review. (2) Supply-air compliance collapsing alongside a declining Cooling ΔT and a saturated chilled-water valve → a coil or valve failure in progress; escalate the AHU. (3) Handlers that lose their discharge only at peak load month after month → a capacity or staging question for the MBR rather than a repeated control fix.
Prevention
(1) Confirm the supply-air setpoint, reset schedule, and sensor calibration per AHU so a deviation reflects the handler, not the target or the sensor. (2) Alert on sustained above-setpoint discharge under a cooling call, weighted to persistence, and separate capacity deviations (riding above setpoint) from erratic ones (controls or mixing). (3) Trend discharge compliance next to Cooling ΔT and valve position so a developing coil or valve fault is visible before it fails, and keep a per-AHU log across visits.