FA-92724 / HVAC thermostat control / Member archive

DCV damper closes past its target · case 04

When CO2 drops the damper keeps closing below the minimum ventilation position.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

CO2 demand-controlled ventilation per sample; samples are [co2_ppm, occupied]. Unoccupied target is 0%. Occupied: min_pos at or below co2_low, max_pos at or above co2_high, and linear in between rounded half up to whole percent. The damper moves toward the target by at most 10 percentage points per sample in either direction. Return the damper position per sample.

Why this case matters

Residential and light-commercial thermostats make these decisions sample by sample; each defect changes equipment calls in a way that shows up as short cycling, comfort complaints or equipment stress.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: scenario 1	`[10, 20, 30, 40, 50, 60, 50, 40, 50]`	`[10, 20, 30, 40, 50, 60, 60, 50, 60]`	Failed

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