BAS-207 Visual Aid Library
Figure-use rule
Each figure is an orientation and reasoning aid, not a project drawing. Learners must pair it with the current sequence, point list, wiring/piping documents, manufacturer instructions, and as-found evidence.
Normal-rule anchor
A passed graphic test does not prove wiring, calibration, equipment safety, or complete sequence.
Case overlay
A project record says the point was checked but records only that the graphic changed.
Calculation/evidence callout: Reconcile required point tests, evidence levels, witnesses, and open claims.
Normal-rule anchor
No checkout begins because a screen is available; readiness and authority are test prerequisites.
Case overlay
A live AHU serves occupied space and the plan has no smoke/freeze interface owner or override register.
Calculation/evidence callout: Calculate test duration/window, target coverage, expected response tolerances, and restoration checklist counts.
Normal-rule anchor
Testing without explicit expected values and states can only prove that something changed.
Case overlay
A binary proof is reversed and an analog range differs between submittal, controller, and graphic.
Calculation/evidence callout: Calculate expected raw/engineering values and tolerances; reconcile all identity/type/range fields.
Normal-rule anchor
A simulated or electrical input proves only the tested path and condition; it may not prove sensing placement or process accuracy.
Case overlay
Room temperature looks correct while the sensor is biased and the input scale offsets it in the opposite direction.
Calculation/evidence callout: Calculate signal conversion, offset/error, tolerance, and reasonableness across low/mid/high or open/closed cases.
Normal-rule anchor
Never jump safeties or power circuits; an interposing relay is tested in the approved control circuit, not a motor power leg.
Case overlay
A fan BO changes and relay clicks, but starter is in Hand and proof remains stale.
Calculation/evidence callout: Calculate response/timeout and reconcile active priority, contact state, equipment proof, and process change.
Normal-rule anchor
A command percentage is not output signal, position, equipment effect, or process result; each layer needs evidence.
Case overlay
A valve command changes 20-80%, feedback follows, but discharge temperature does not respond.
Calculation/evidence callout: Calculate expected signal, command-feedback deviation, stroke/settling time, and reasonable process direction/magnitude.
Normal-rule anchor
Every screen value/action is a claim about source, time, quality, authority, and physical meaning.
Case overlay
A graphic shows Normal because stale status is hidden and a schedule writes at a higher priority than the test.
Calculation/evidence callout: Reconcile priorities, units/enums, freshness, history interval, alarm timing, and schedule precedence.
Normal-rule anchor
Replacing devices or forcing values before preserving evidence destroys the path to root cause.
Case overlay
An input reads zero after renovation; possible causes include process condition, power, open loop, wrong landing, scale, or object binding.
Calculation/evidence callout: Compare predicted outcomes for each hypothesis and quantify which test eliminates the most causes within safety/authority.
Normal-rule anchor
A fixed point with an active override, disabled alarm, connected jumper, or wrong equipment mode is a failed checkout.
Case overlay
The point passes after a scale change, but OOS remains true and a temporary schedule override persists.
Calculation/evidence callout: Reconcile every temporary state and calculate pass/retest/regression/restoration completeness.
Normal-rule anchor
Checkout supports decisions; it does not grant authority or erase unresolved safety, process, documentation, or recovery risk.
Case overlay
Most points pass, but one safety interface, two command/proof contradictions, and an untested restart case remain.
Calculation/evidence callout: Calculate coverage and pass rates without averaging critical failures; reconcile open risks and owners.