FA-92674 / HVAC thermostat control / Member archive

Compressor start resets the degree-minute integral · case 04

The compressor stops within minutes of starting because the integral was zeroed.

Member previewVariant 4 · 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: scenario 4	`[[-26, false, false], [-49, false, false], [0, true, false], [-27, true, false], [-55, true, false], [-75, true, false], [-103, true, false], [-124, true, false], [-150, true, false], [-170, true, false]]`	`[[-26, false, false], [-49, false, false], [-72, true, false], [-99, true, false], [-127, true, false], [-147, true, false], [-175, true, false], [-196, true, false], [-222, true, false], [-242, true, false]]`	Failed

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