FA-92763 / HVAC thermostat control / Member archive

Optimal start has no maximum lead time · case 03

After a very cold night the system starts recovering many hours before occupancy.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Optimal start for a heating setback, sampled per minute from minute 0; rate is the recovery rate in tenths F per hour. While not recovering, required minutes = ceil(max(0, occ_sp - temp) * 60 / rate); recovery starts (and latches) when minutes left until occupancy <= required, but never more than 180 minutes early, and in any case at occupancy. Return the active setpoint per minute.

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: lead limit	`[700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700, 700]`	`[600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 700, 700, 700, 700, 700]`	Failed

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