FA-92569 / HVAC thermostat control / Member archive

Blower starts with the burner and blows cold air · case 04

At the start of every heating call the occupants feel a draft of unheated air.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Thermostat G (blower) output per minute; samples are the equipment call per minute (None, heat or cool). Cooling runs the fan immediately and keeps it on 2 minutes after the call ends. Heating starts the fan only from the second minute of a heat call (heat exchanger warm-up) and, if the fan had started, keeps it on 3 minutes after the call. Fan mode on forces the fan on. Circulate mode ensures at least 20 fan minutes per clock hour (minutes 0-59, 60-119, ...), counting all fan minutes, by running the fan once the remaining minutes in the hour equal the remaining requirement. Return the fan state 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 1	[false, false, false, false, false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false]	[false, false, false, false, false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false, true, true, true, true, true, true, true, true, true, true, true, true, true, true, true, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, false, true, true, true, false, true, false, true, true, true, true, false, false, false, false, false, false, false, false]	Failed

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