Equipment fails slowly. The supply temp drifts 2°F. The chilled water valve hunts. The economizer leaks. Signal FDD catches these patterns weeks before alarms surface or tenants complain.
Six fault families across HVAC, controls, and metering systems.
Failed sensors, stuck dampers, hunting valves, simultaneous heating and cooling, low delta-T syndrome, degraded heat exchangers.
Sequences that no longer match the design intent. Manual overrides left active. Schedule violations. Setpoints overridden at the device level.
Off-hours consumption, schedule mismatches, weekend baseline drift. Tied to building schedules and weather.
Self-learning baselines flag deviations the rule library missed. Catches degradation patterns weeks ahead of alarm thresholds.
Live FDD scoring across every check across every asset. Color-coded by severity, ranked by impact, drilled into by trend. The fault is not just "AHU-3 is bad." The fault is "FDD-1842: AHU-3 economizer leakage causing 14% supply-air over-cooling."
How this looks in your stack.
id: FDD-1842 name: "Economizer leak detection" applies_to: ["ahu", "rtu"] when: oat: "> 75 °F" economizer_cmd: "closed" supply_temp_delta: "> 4 °F below setpoint" duration: "> 30 min" severity: 3
{
"fdd_code": "FDD-1842",
"asset": "@b3.ahu-3",
"first_seen": "2026-05-09T04:13Z",
"impact_kw": 14.2,
"severity": 3,
"recommend_wo": true,
"runbook": "economizer-actuator.pdf"
}On-premise by default. Cloud-deployable when required. Your facility data never leaves your network.
TLS everywhere, secrets in vault, row-level security on every query. Containerized and isolated so one service going down never takes the rest with it.
A·IQ is built by Arcis FM, a Service-Disabled Veteran-Owned Small Business (SDVOSB). Set-aside eligible for federal contracts. CAGE 14DG6 · UEI Z95MQL2KEYG3.
Engineer and operator questions on this capability.
40+ baked-in rules across HVAC equipment, controls sequences, and energy patterns plus ML-driven anomaly detection that learns your building's baseline.
No. The default library covers most equipment types out of the box. Custom rules for unusual sequences or proprietary equipment can be added.
Alarms are reactive they fire when a threshold is crossed. FDD is proactive it identifies sequences that will cause an alarm if not addressed.
Yes. With Nexus, every detected fault can auto-create a work order with the runbook, parts list, and assigned technician attached.
FDD finds the fault. RCA finds the cause. Work orders close the loop.
Send us 30 days of BAS history. We will run our FDD library against it and show you the faults already happening in your building right now.
