DOAS / ERV / exhaust faults
Dedicated outdoor air, energy recovery and exhaust.
Five rules for the ventilation path: DOAS units missing their supply setpoint, energy-recovery bypass open when recovery pays, exhaust running without supply, exhaust outside its schedule, and building pressure out of band. Ventilation faults show up as humidity, infiltration and envelope moisture as often as they show up on the bill.
How to read it. One day of a ventilation system. The two bars show when the supply fan and the exhaust fan are running; the line is building pressure relative to outdoors. After 18:00 the supply fan stops but the exhaust keeps going (red), and the building is pulled negative, drawing in unconditioned air through the envelope.
The rules
- BP-01
Building pressure out of band
Building static pressure is negative or excessive during occupancy.
Diagnostic · reliabilityBAS trends - DOAS-01
DOAS supply setpoint not met
The dedicated outdoor-air unit's supply temperature misses its setpoint for an hour or more while running.
Diagnostic · comfortBAS trends - EF-01
Exhaust running without supply
Exhaust fans run while the supply fan is off.
Capacity-basedBAS trends - EF-02
Exhaust running outside the schedule
General exhaust runs during unoccupied hours.
Capacity-basedBAS trends - ERV-02
Energy-recovery bypass open when recovery pays
The recovery bypass is open while indoor and outdoor temperatures differ a lot.
Capacity-basedBAS trends
See these rules run on your building.
Send twelve months of interval data and a BAS trend export. Energy Agent returns a ranked list of what is wasting money, what each item is worth per year at your tariff, and what to do about it.