FA-92657 / HVAC thermostat control / Member archive

Degree-minutes integrate target minus supply · case 02

A cold supply drives DM positive and the compressor never starts.

Member previewVariant 2 · 3 implementations · 8 checks per implementation

Case contract

Hydronic heat pump degree-minute controller, one sample per minute of [supply_temp, target_supply] in whole F. Degree-minutes DM accumulate supply - target each minute and are clamped to [floor, 100]. The compressor starts when DM <= start_dm and stops when DM >= stop_dm. Auxiliary heat starts when DM <= aux_dm and stops when DM >= start_dm. Decisions use the DM value after this minute's update. Return [DM, compressor, aux] 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: long surplus	`[[-30, false, false], [-60, true, false], [-90, true, false], [-120, true, true], [-150, true, true], [-150, true, true], [-130, true, true], [-110, true, true], [-90, true, true], [-70, true, true], [-50, true, false]]`	`[[30, false, false], [60, false, false], [90, false, false], [100, false, false], [100, false, false], [100, false, false], [80, false, false], [60, false, false], [40, false, false], [20, false, false], [0, false, false]]`	Failed

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