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FA-92386 / HVAC thermostat control / Open access

Safety fault waits for the compressor minimum on time · case 01

A high-pressure or overload fault keeps the compressor running until its minimum run time expires.

Verified by executionVariant 1 · 8 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The safety stop is folded into the normal stop test that is gated by minimum on time.

THE FAILURE

The safety stop is folded into the normal stop test that is gated by minimum on time.

Unsuccessful approach: Acting on the safety fault only while demand is still present ignores faults after the call ends.

Case contract

Compressor protection sampled per minute; calls is a list of [demand, safety_ok]. After power-up the compressor may not start before minute startup_delay. Once started it runs at least min_on minutes even if demand ends; after stopping it stays off at least min_off minutes. A safety fault stops it immediately regardless of minimum on time, and that stop also starts the minimum off time; it cannot start while the safety is faulted. Return the compressor 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.

1 / The failure

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(min_on, min_off, startup_delay, calls):
    running = False
    on_at = None
    off_at = None
    out = []
    for minute, (demand, safety_ok) in enumerate(calls):
        if running:
            if (not demand or not safety_ok) and minute - on_at >= min_on:
                running = False
                off_at = minute
        elif demand and safety_ok and minute >= startup_delay:
            if off_at is None or minute - off_at >= min_off:
                running = True
                on_at = minute
        out.append(running)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [3,
    3,
    4,
    [[False, False],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True]]],
   [False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 2',
   [5,
    3,
    0,
    [[True, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True]]],
   [True, True, True, False, False, False, True, True, False, False, False, False, False, True]],
  ['regression: scenario 3',
   [3,
    4,
    0,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [True, True, True, True, False, False, False, False, True, False, False]],
  ['control: scenario 4',
   [5,
    5,
    4,
    [[True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, False]]],
 [['regression: scenario 3',
   [3,
    4,
    0,
    [[True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [True, True],
     [False, True],
     [False, True]]],
   [True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True]],
  ['regression: scenario 7',
   [2,
    3,
    2,
    [[True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, False]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['control: scenario 1',
   [5,
    3,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False, False, False, False, False, True, True, True, True, True, True, True]],
  ['control: scenario 2',
   [2,
    5,
    4,
    [[False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True]]],
   [False, False, False, False, False, True, True, True, False, False, False, False, False, False]]],
 [['regression: scenario 2',
   [2,
    4,
    0,
    [[False, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True]]],
   [False,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 18',
   [3,
    3,
    0,
    [[False, True],
     [False, True],
     [True, True],
     [False, False],
     [True, True],
     [False, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, True]]],
   [False, False, True, False, False, False, False, True, True, True, False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [2,
    5,
    2,
    [[True, False],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, False],
     [True, True]]],
   [False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False]],
  ['regression: scenario 3',
   [2,
    5,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True]]],
 [['regression: scenario 10',
   [5,
    3,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, False],
     [False, True]]],
   [False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 32',
   [2,
    4,
    4,
    [[False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [5,
    4,
    2,
    [[False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True]]],
   [False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    False]],
  ['control: scenario 2',
   [2,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, False]]],
   [False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    False]]],
 [['regression: scenario 15',
   [3,
    4,
    0,
    [[True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, False]]],
   [True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 31',
   [2,
    4,
    2,
    [[False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [True, True],
     [True, False],
     [True, True]]],
   [False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    True]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['control: scenario 1',
   [3,
    4,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [False, True]]],
   [False, False, False, False, True, True, True, False, False, False, False]],
  ['control: scenario 2',
   [2,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True]]],
   [False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    False]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: safety during min on[True, True, True, True, True, True, True][True, True, False, False, False, True, True]Failed
regression: scenario 1[False, False, False, False, False, True, True, True, True, True, False, False, False, False, True, True, True, False, False, False, False, False][False, False, False, False, False, True, True, True, True, True, False, False, False, False, True, True, False, False, False, False, False, False]Failed
control: min on and off[False, False, True, True, True, False, False, False, False, False, True][False, False, True, True, True, False, False, False, False, False, True]Passed
control: safety then quick recall[True, True, False, False, False, False, True][True, True, False, False, False, False, True]Passed
control: exact min on[True, True, False, False, False, True, True, False, False, False, True, True][True, True, False, False, False, True, True, False, False, False, True, True]Passed
regression: scenario 2[True, True, True, True, True, False, False, False, False, False, False, False, False, True][True, True, True, False, False, False, True, True, False, False, False, False, False, True]Failed
regression: scenario 3[True, True, True, True, False, False, False, False, True, True, True][True, True, True, True, False, False, False, False, True, False, False]Failed
control: scenario 4[False, False, False, False, False, False, False, False, False, False, False, False, False][False, False, False, False, False, False, False, False, False, False, False, False, False]Passed

SHA-256 / c9405c2cd138e26689f1a12758629c8a9dc225df74bbf16d5c7eb9299feea533

2 / The unsuccessful fix

Exit 1
"""Failure Map reference implementation. Python standard library only."""
import json

N = 1
observations = []
def solve(min_on, min_off, startup_delay, calls):
    running = False
    on_at = None
    off_at = None
    out = []
    for minute, (demand, safety_ok) in enumerate(calls):
        if running:
            if not safety_ok and demand:
                running = False
                off_at = minute
            elif not demand and minute - on_at >= min_on:
                running = False
                off_at = minute
        elif demand and safety_ok and minute >= startup_delay:
            if off_at is None or minute - off_at >= min_off:
                running = True
                on_at = minute
        out.append(running)
    return out
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
fixtures = [[['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [3,
    3,
    4,
    [[False, False],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True]]],
   [False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 2',
   [5,
    3,
    0,
    [[True, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True]]],
   [True, True, True, False, False, False, True, True, False, False, False, False, False, True]],
  ['regression: scenario 3',
   [3,
    4,
    0,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [True, True, True, True, False, False, False, False, True, False, False]],
  ['control: scenario 4',
   [5,
    5,
    4,
    [[True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True]]],
   [False, False, False, False, False, False, False, False, False, False, False, False, False]]],
 [['regression: scenario 3',
   [3,
    4,
    0,
    [[True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [True, True],
     [False, True],
     [False, True]]],
   [True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True]],
  ['regression: scenario 7',
   [2,
    3,
    2,
    [[True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, False]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['control: scenario 1',
   [5,
    3,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False, False, False, False, False, True, True, True, True, True, True, True]],
  ['control: scenario 2',
   [2,
    5,
    4,
    [[False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True]]],
   [False, False, False, False, False, True, True, True, False, False, False, False, False, False]]],
 [['regression: scenario 2',
   [2,
    4,
    0,
    [[False, True],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True]]],
   [False,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 18',
   [3,
    3,
    0,
    [[False, True],
     [False, True],
     [True, True],
     [False, False],
     [True, True],
     [False, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, True]]],
   [False, False, True, False, False, False, False, True, True, True, False]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [2,
    5,
    2,
    [[True, False],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, False],
     [True, True]]],
   [False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False]],
  ['regression: scenario 3',
   [2,
    5,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, False],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True]]],
 [['regression: scenario 10',
   [5,
    3,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [False, True],
     [False, False],
     [False, True]]],
   [False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 32',
   [2,
    4,
    4,
    [[False, True],
     [False, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [False,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['regression: scenario 1',
   [5,
    4,
    2,
    [[False, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True]]],
   [False,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    False]],
  ['control: scenario 2',
   [2,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [False, True],
     [False, False]]],
   [False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    False]]],
 [['regression: scenario 15',
   [3,
    4,
    0,
    [[True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [True, False],
     [True, True],
     [False, True],
     [False, True],
     [False, False]]],
   [True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    False,
    False]],
  ['regression: scenario 31',
   [2,
    4,
    2,
    [[False, True],
     [True, True],
     [True, False],
     [True, True],
     [True, False],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, False],
     [False, True],
     [False, True],
     [True, False],
     [True, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [True, True],
     [True, False],
     [True, True]]],
   [False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    False,
    False,
    False,
    False,
    False,
    True]],
  ['control: min on and off',
   [3,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, False],
     [True, True]]],
   [False, False, True, True, True, False, False, False, False, False, True]],
  ['regression: safety during min on',
   [5,
    3,
    0,
    [[True, True], [False, True], [False, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, True, True]],
  ['control: safety then quick recall',
   [2,
    4,
    0,
    [[True, True], [True, True], [True, False], [True, True], [True, True], [True, True], [True, True]]],
   [True, True, False, False, False, False, True]],
  ['control: exact min on',
   [2,
    3,
    0,
    [[True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True]]],
   [True, True, False, False, False, True, True, False, False, False, True, True]],
  ['control: scenario 1',
   [3,
    4,
    0,
    [[False, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [False, True],
     [True, True],
     [False, True],
     [False, False],
     [False, False],
     [False, True]]],
   [False, False, False, False, True, True, True, False, False, False, False]],
  ['control: scenario 2',
   [2,
    4,
    2,
    [[True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True],
     [False, True],
     [False, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [True, True],
     [False, True]]],
   [False,
    False,
    True,
    True,
    True,
    False,
    False,
    False,
    False,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    True,
    False]]]]
for label, args, expected in fixtures[N-1]:
    check(label, solve(*args), expected)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)
Boundary fixtureActualExpectedOutcome
regression: safety during min on[True, True, True, True, True, True, True][True, True, False, False, False, True, True]Failed
regression: scenario 1[False, False, False, False, False, True, True, True, True, True, False, False, False, False, True, True, True, False, False, False, False, False][False, False, False, False, False, True, True, True, True, True, False, False, False, False, True, True, False, False, False, False, False, False]Failed
control: min on and off[False, False, True, True, True, False, False, False, False, False, True][False, False, True, True, True, False, False, False, False, False, True]Passed
control: safety then quick recall[True, True, False, False, False, False, True][True, True, False, False, False, False, True]Passed
control: exact min on[True, True, False, False, False, True, True, False, False, False, True, True][True, True, False, False, False, True, True, False, False, False, True, True]Passed
regression: scenario 2[True, True, True, False, False, False, True, True, False, False, False, False, False, True][True, True, True, False, False, False, True, True, False, False, False, False, False, True]Passed
regression: scenario 3[True, True, True, True, False, False, False, False, True, False, False][True, True, True, True, False, False, False, False, True, False, False]Passed
control: scenario 4[False, False, False, False, False, False, False, False, False, False, False, False, False][False, False, False, False, False, False, False, False, False, False, False, False, False]Passed

SHA-256 / fb0fe3ad1f47b3700f4055f2bc2b7fb1eb24153faef9352d6d893c12e7806034

HELD IN THE MEMBER ARCHIVE

The verified repair and its recorded checks are member-only.

This mechanism has 8 recorded checks per implementation. The open-access tier publishes the failure and the unsuccessful fix; the repaired source that passes every check, and the observations that prove it, are available to members.

Every case sharing this mechanism uses the same contract and the same repair, so this one record is held back for all of them.

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Verification & scope

A deterministic bounded teaching model of one thermostat or HVAC controller decision evaluated per sample. Temperatures are integer tenths of a degree Fahrenheit unless stated otherwise. The contract is a stipulated toy convention, not a claim of conformance to any manufacturer, ASHRAE guideline or code. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.

Observations recorded using Python 3.12.14 at 2026-09-29T14:51:45.175473+00:00.

Case digest / 829b82c00f03626b58335620a3fc277c65cb7fdbbef1133839255c320e2be15d