BAS-309 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
The work order defines the assigned problem and authority; it does not prove the cause or permit every technically possible action.
Case overlay
A customer reports that the west wing is hot and asks the technician to force cooling immediately.
Calculation/evidence callout: Reconcile requested, authorized, completed, deferred, and open work counts; the categories must balance.
Normal-rule anchor
Technical ability is not authorization; access must be named, least-privilege, time-bounded, logged, and closed.
Case overlay
A shared administrator credential is offered for a quick remote check of a production supervisor.
Calculation/evidence callout: Compare session start/end, reservation window, authorized target count, and access-closure evidence.
Normal-rule anchor
Ask for time, place, operating mode, impact, and recent changes before asking the customer to agree with a technical theory.
Case overlay
Three occupants say the room is always cold, but the complaint occurs only during Monday morning warm-up.
Calculation/evidence callout: Build a timestamped event line and compare complaint windows to schedule, occupancy, weather, and system-mode windows.
Normal-rule anchor
A screenshot without point identity, timestamp, units, mode, source, and revision is an illustration, not sufficient diagnostic evidence.
Case overlay
A graphic looks wrong after a recent controls upgrade, but the technician has an old point list and no change record.
Calculation/evidence callout: Reconcile document revision dates and trend time bases; calculate clock offset before comparing events.
Normal-rule anchor
The as-found condition must be recorded before a test, reset, override, restart, cover removal, or setpoint change can alter it.
Case overlay
The technician arrives to find a panel door open, a VFD in HAND, and an unrecorded alarm inhibit.
Calculation/evidence callout: Count and reconcile every temporary/manual/open state before and after work; zero unaccounted states is required.
Normal-rule anchor
A professional update states what is known, unknown, being tested, affected, and expected next without guaranteeing an unproven outcome.
Case overlay
An initial one-hour visit becomes a multi-trade investigation after the BAS evidence points toward a mechanical restriction.
Calculation/evidence callout: Compare planned and actual elapsed time, interruption duration, and next-update commitment with stated assumptions.
Normal-rule anchor
Escalation is a professional technical action when the next test belongs to another qualified role or exceeds assigned authority.
Case overlay
A manager asks the BAS technician to bypass a freezestat so the air handler can run for a demonstration.
Calculation/evidence callout: Use a risk matrix with severity, likelihood, detectability, and reversibility; any life-safety boundary overrides convenience scoring.
Normal-rule anchor
Closing the software window is not restoration; the physical, controller, network, alarm, schedule, and access states must be proven.
Case overlay
A test override fixes the complaint, but the technician cannot identify the original priority source.
Calculation/evidence callout: Reconcile all commands, forces, jumpers, test modes, open enclosures, temporary accounts, and alarms to an explicit as-left state.
Normal-rule anchor
The record distinguishes evidence from inference and states both the confirmed cause and what remains unknown.
Case overlay
The immediate comfort issue is corrected, but a recurring network dropout remains unproven and requires follow-up.
Calculation/evidence callout: Check that planned actions equal completed plus deferred plus cancelled, and that every open item has one owner and due date.
Normal-rule anchor
A service visit is not complete because the customer is temporarily comfortable; it closes only with truthful evidence, restoration, ownership, and communication.
Case overlay
A technician is pressured to report a sensor replacement as complete before the failed reference check is repeated.
Calculation/evidence callout: Reconcile labor, material, test, retest, and open-item records; critical evidence cannot be averaged away by a high overall score.