Technical Trade SchoolBAS-100 foundation-series
BAS-104
Concept reading and source route

BAS-104 Reading Guide

How to use this reading guide

This is the concept-review layer for a 100% online course. Read each module before its lesson, complete the retrieval prompts without looking, then use the linked authoritative sources to verify project-specific editions, requirements, and manufacturer procedures.

Online evidence is not OJL: browser simulations, document cases, and isolated remote equipment build reasoning and documentation skill; supervised field performance is recorded separately.

Module 1

Device-to-process mental model and source hierarchy

Why it matters: A device is not selected by point type alone; process, range, dynamics, environment, installation, integration, service, and source authority all matter.

Vocabulary and working scope

Process variable; point requirement; sequence; schedule/submittal; model; range; accuracy; output; power; environment; location; access; authority; replacement equivalence.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A duct sensor model meets range but not insertion depth, environment, or replacement-access requirements.

Calculation: Calculate requirement coverage, range utilization, accuracy impact, and unresolved source conflicts.

Retrieval prompts

Module 2

Temperature sensors and representative placement

Why it matters: A precise sensor in an unrepresentative location creates precise bad evidence.

Vocabulary and working scope

Thermistor/RTD/transmitter awareness; room/duct/pipe/immersion/averaging/outdoor; range; accuracy; response; radiation; stratification; conduction; wells; insertion; airflow; calibration.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A space sensor sits on an exterior wall above equipment and reads warm while the occupied zone is cool.

Calculation: Calculate sensor error/offset, averaging, response comparison, insertion/coverage from supplied criteria, and control impact.

Retrieval prompts

Module 3

Humidity, CO2, IAQ, light and occupancy sensing

Why it matters: Sensor output depends on technology, location, maintenance, time, and context; project ventilation and health decisions require governing sources and qualified review.

Vocabulary and working scope

RH/dew point; CO2 as ventilation indicator; VOC/PM awareness; occupancy/presence; light; drift; contamination; warm-up; placement; outdoor-air reference; calibration; limitations.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A wall CO2 sensor near a door reads outdoor air while occupants report stuffiness in the room center.

Calculation: Calculate ppm difference, percent outside band, dew-point margin from supplied data, calibration offset, and sampling/occupancy timing.

Retrieval prompts

Module 4

Pressure, differential pressure, airflow pickups and tubing

Why it matters: A transducer measures the pressure relationship delivered to its ports, not necessarily the intended airflow or filter condition.

Vocabulary and working scope

Static/differential pressure; low/high ports; reference; pitot/crossflow pickup; KMC SSS awareness; tubing material/route/slope; kinks/leaks/condensate; zero; range; square-root relationship; location.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A hybrid VVT box reads high airflow because high/low tubes are reversed and the pickup is installed near a disturbance.

Calculation: Calculate DP polarity, airflow from supplied K-factor/equation, percent-of-range, error propagation awareness, and tubing/elevation reasonableness.

Retrieval prompts

Module 5

Flow, level, current and equipment-proof devices

Why it matters: Proof must match the consequence: current may show energized load but not airflow, rotation, belt condition, or delivered capacity.

Vocabulary and working scope

Air/water flow switches/transmitters; current switch/transducer; differential proof; level; pulse; contact state; threshold; deadband; time delay; mounting; false proof; independent evidence.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A fan current switch proves while a broken belt leaves airflow near zero.

Calculation: Calculate threshold/margin, analog scaling, delay, false-positive/negative coverage, and command-to-proof timing.

Retrieval prompts

Module 6

Valves, actuators and hydronic final control elements

Why it matters: Command and displayed position do not prove valve travel, flow, seat closure, or heat transfer.

Vocabulary and working scope

Two/three-way valve; equal-percentage/linear awareness; fail position; close-off; actuator torque/force; stroke; linkage; command/position; leakage; authority awareness; isolation/balance; coil response.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A heating valve reports 100 percent while linkage slips and coil delta T remains near zero.

Calculation: Calculate signal-to-position scaling, stroke time, command/feedback error, supplied close-off/torque margin, and heat-transfer response.

Retrieval prompts

Module 7

Dampers, actuators and airside final control elements

Why it matters: An actuator shaft turning does not prove blades move or air changes; listed smoke/fire assemblies and testing have separate authority.

Vocabulary and working scope

Blade/linkage; opposed/parallel awareness; outdoor/return/exhaust/terminal/fire-smoke boundaries; fail position; torque; rotation; stroke; end stops; leakage; command/feedback; mechanical binding.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

An economizer actuator drives while a disconnected linkage leaves outdoor-air dampers closed.

Calculation: Calculate rotation/position, stroke timing, supplied torque margin, outdoor-air fraction, and expected airflow/temperature change.

Retrieval prompts

Module 8

Relays, current switches, contact interfaces and safeties

Why it matters: BAS relays belong in approved control interfaces, not motor-power legs, and BAS logic does not replace hardwired/listed safety function.

Vocabulary and working scope

Coil/contact; SPDT/DPDT; interposing relay/RIB; contact rating; dry/wet; starter/VFD control; current proof; pressure/temperature limits; hardwired safety; BAS monitoring; bypass prohibition.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A boiler enable relay is correct, but its proof point is mapped to the command contact rather than burner status.

Calculation: Build truth tables, calculate coil/load and contact-rating margin from supplied data, and compare command/proof timing.

Retrieval prompts

Module 9

Power, signals, grounding/reference, shielding and termination

Why it matters: Common, ground, reference, and shield are not interchangeable; correct signal type with wrong reference is still wrong.

Vocabulary and working scope

24 Vac/dc; resistance; 0-10 V; 4-20 mA; binary; pulse; polarity; common/reference; earth; shield/drain; isolation; terminal conductor range; strip/torque process; noise; VFD proximity.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A 0-10 V pressure sensor drifts whenever a VFD runs because its reference and shield are misapplied.

Calculation: Calculate voltage drop, loop scaling, source/load VA/current, expected readings, and noise/error comparisons.

Retrieval prompts

Module 10

Calibration, verification, uncertainty and changed failures; Device diagnosis, documentation and OJL handoff

Why it matters: Adjustment is not automatically correction; first establish reference quality, installation, range, repeatability, tolerance, and process impact. Online mastery supports preparation, not a false field qualification; document both evidence and limits.

Vocabulary and working scope

Calibration versus functional check; reference standard; traceability awareness; as-found/as-left; offset/span; multi-point; environment; tolerance; uncertainty; nonadjustable devices; replacement; retest. Complaint; physical/process evidence; signal; object; command; proof; device/mechanical/wiring/tubing/database hypotheses; next safe test; issue/retest; redline; photos; as-left; OJL.

Source-to-result trace

  1. Locate the controlling requirement and establish authority.
  2. Identify the physical and digital boundaries.
  3. Preserve as-found state and timestamps.
  4. Trace the initiating condition through logic, interfaces, equipment, and process response.
  5. Compare expected and actual evidence.
  6. Calculate with units and stated tolerance.
  7. Record action, result, restoration, uncertainty, and owner.

Worked thinking prompt

A sensor is adjusted at one point to match a questionable handheld reference and becomes worse across its operating range. Changed case: A zone is hot with normal sensor value, full cooling command, no actuator feedback, and a kinked pneumatic-style tubing remnant near a retrofit device.

Calculation: Calculate error, percent span, offset/slope from supplied points, tolerance/uncertainty stack awareness, and pass/fail coverage. Calculate evidence coverage, response timing, error/range, test discrimination, artifact completeness, and temporary-state closure.

Retrieval prompts

Required and deeper reading

Adoption note: Standards, codes, project requirements, owner criteria, manufacturer instructions, and employer safety programs control. Confirm the adopted edition and authority before applying a numeric requirement.