Which is a common cause of unoccupied setpoint drift, and how is it corrected?

Which is a common cause of unoccupied setpoint drift, and how is it corrected?

• A. Power supply fluctuations; replace power supply
• B. Visual interface misalignment; reset display
• C. Firmware update; revert to previous version
• D. Misconfigured schedules or sensor drift; corrected by recalibrating sensors and updating schedules during commissioning

Answer: (D)

Unoccupied setpoint drift happens when the temperature target for times when a space is not occupied starts to creep away from the intended value. In practice, this most often comes from sensors that have drifted over time or from control logic that isn’t correctly configured, so the system ends up applying the wrong setpoint during unoccupied periods. The way to fix it is to address both sensor accuracy and the control schedules: recalibrate or replace sensors so their readings reflect actual temperatures, and review and update the commissioning data and schedules so that the unoccupied setpoint is defined correctly and enforced at the right times. This often involves validating that the controller switches to the intended unoccupied setpoint, and removing any conflicting rules or overrides in the logic. Power supply fluctuations typically cause intermittent or broader faults rather than a steady drift in the unoccupied setpoint, display misalignment affects only what you see on the interface, and a firmware update might change behavior but isn’t the direct, common cause of drift.

Unoccupied setpoint drift happens when the temperature target for times when a space is not occupied starts to creep away from the intended value. In practice, this most often comes from sensors that have drifted over time or from control logic that isn’t correctly configured, so the system ends up applying the wrong setpoint during unoccupied periods. The way to fix it is to address both sensor accuracy and the control schedules: recalibrate or replace sensors so their readings reflect actual temperatures, and review and update the commissioning data and schedules so that the unoccupied setpoint is defined correctly and enforced at the right times. This often involves validating that the controller switches to the intended unoccupied setpoint, and removing any conflicting rules or overrides in the logic. Power supply fluctuations typically cause intermittent or broader faults rather than a steady drift in the unoccupied setpoint, display misalignment affects only what you see on the interface, and a firmware update might change behavior but isn’t the direct, common cause of drift.