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HVAC Fault Injection Simulator

Single-zone AHU · Cooling coil · OA damper · Inject faults · Watch the FDD respond

✅
Normal operation — no faults detected
All readings within tolerance. Supply-air temp at setpoint and coil within capacity.

🌡️ Operating Conditions

Outdoor air temp (OAT)90 °F
Return air temp (RAT)75 °F
Cooling SAT setpoint55 °F
Design supply airflow8000 CFM
Cooling coil capacity20 tons

💉 Fault Injection

Healthy operation — all components nominal.
ASHRAE Guideline 36 / FDD:Automated fault detection & diagnostics for single-zone AHUs cross-checks supply-air temperature, coil energy balance, and outdoor-air fraction against expected behavior. Persistent SAT error, coil saturation, or excess OA at high OAT flag mechanical or sensor faults for maintenance.
Baseline (healthy) vs Current (faulted) — sensible energy balance
0%25%50%75%100%Metric (baseline vs faulted)% of metric scale55.0°55.0°Actual SAT (°F)16.616.6Coil Load (tons)83%83%% Capacity
Baseline (healthy)
Current (faulted)

📊 AHU Readouts

Mixed air temp (MAT)
78.0 °F
OA fraction
20 %
Required cooling
16.6 tons
Delivered cooling
16.6 tons
% Capacity used
83 %
Actual SAT
55.0 °F
SAT error
0.0 °F
Energy penalty
0.0 kBTU/hr
Active fault
None