Night setback that never happened

Background

A distribution warehouse uses an overnight setback schedule for its heating, ventilation and air conditioning. The schedule is intended to reduce demand during the quieter period. Our monitoring follows the electrical feeds to the HVAC equipment so the team can see how the equipment actually runs through the night.

The problem

The automation schedule reports that setback is active. The electrical trace shows a different pattern, night after night. Because the setting still appears to be in place, the team has little reason to revisit it from the schedule alone. The missing reduction stays hidden until actual demand is compared with the expected overnight behaviour.

How we found it

We use current transformers on the main HVAC feeds and follow demand at minute resolution. The trace shows whether the expected change occurs when the schedule calls for setback. Overnight baseline alerts draw attention to demand that remains above the expected level, giving the team a particular night and period to investigate.

What changed

The setback schedule is restored, reducing the overnight electrical load. Its effect is now measured as well as scheduled. The team can follow the demand trace after the change and receive an alert when the expected overnight pattern fails to appear, rather than relying on the control setting as confirmation.

The lesson

Check the schedule against actual electrical demand. Use the overnight baseline to confirm that setback continues working after changes to the schedule or equipment.