What is FDD?
Fault detection and diagnostics (FDD) is software that compares equipment and sensor data with expected behavior, flags faults such as stuck dampers or simultaneous heating and cooling, and names the likely cause.
Where FDD runs
FDD reads the points a building automation system already exposes: temperatures, pressures, valve and damper positions, fan status and energy. It is used on air handlers, rooftop units, VAV boxes, chillers and boilers in offices, hospitals, campuses and airports, by energy managers, controls contractors and in-house engineers.
What the evidence shows
A Lawrence Berkeley National Laboratory analysis of more than 60,000 pieces of HVAC equipment found that on any given day 40 percent of air handling units and 30 percent of terminal units showed a reported fault. In the DOE Smart Energy Analytics Campaign, covering about 6,000 buildings, fault detection and diagnostics delivered median savings of 9 percent with a one to two year payback.
How Aqueduct presents a fault
On a rooftop unit, Aqueduct's twin shows component states rather than raw points: economizer, damper position, compressor and fan status, and supply air temperature. Setpoint attainment, comfort compliance and sequence exceptions show whether the unit is following its sequence, and a maintenance alert can be triggered from any metric, including one from a linked sensor.