A systematic BAS diagnostic methodology — field value vs. front-end value, controller and communication status, programming logic, and manual overrides — applied to the common failure modes every controls technician eventually encounters, plus the documentation and escalation practices that make troubleshooting an institutional capability.
Faced with a zone that will not hold temperature, the instinctive move is to start changing something and see if the symptom clears — a habit that works often enough to be tempting and fails often enough to be dangerous. This module builds a systematic, four-step methodology that separates correlation from causation before a fix is applied: verify the point value at the field device against the front end, check controller and communication status, review programming logic against the actual sequence of operation, and explicitly check for manual overrides that are invisible to the program's own logic.
By the end of this module you should be able to distinguish a stuck actuator from a failed sensor even when both produce the identical symptom, recognize a scattered multi-equipment fault pattern that actually traces to one communication trunk device, and know when a finding should escalate immediately rather than continue on trial and error — closing the loop this program opened in Module 13 on integration and Module 14 on commissioning.