Graphic Says Auto — But Something Else Owns the Point
The graphic shows Auto/Run, yet the fan or valve ignores the BAS. Walk the control chain from the HOA and VFD faceplate through safeties and the BACnet priority array before rewriting logic.
Operator or graphic shows Auto (or a run/speed command), but the equipment stays off, runs full speed, or won't follow the BAS speed/position command. Callbacks often sound like "BAS isn't working."
• Go physical first — find the real HOA, VFD keypad, and bypass selector (mezzanines and behind ductwork count). Photograph as-found positions.
• VFD faceplate: Local vs Remote/Auto, speed source, faults, min/max clamps.
• Bypass package: DRIVE / BYPASS / OFF — if Bypass is active, "30% command" can still mean across-the-line full speed.
• Safeties and proofs: freezestat, smoke, HP/LP, door interlocks, AUX/DP proof when commanded.
• Clamp-meter reality check: if BAS says RUN but amps are ~0 A, the block is upstream of the motor.
1. Compare commanded value → controller output → electrical signal → actuator/starter → mechanical movement → proof feedback (Field Kit control chain).
2. Read the BACnet Priority_Array and Relinquish_Default. Anything written above the program slot wins; clear leftover Manual_Operator / force values to Null, not just zero.
3. Confirm schedules, holidays, smoke/freeze supervisory modes, and global min-speed floors aren't asserting control.
4. Audit graphic binding — legacy jobs sometimes point pretty tags at retired objects. Expose Proven On beside Command.
5. Trend 10–15 minutes after a test start: catch min-off timers, lockouts, and oscillations a snapshot misses.
• Panel HOA not in Auto, or VFD left in Local
• Bypass contactor pulled in (manual or auto-bypass after a drive fault)
• Open proof/interlock chain (AUX, DP, freezestat)
• Higher BACnet priority write still active
• RS-485 noise near VFD leads making "Auto" look unresponsive (commands never land)
• Min-speed clamp / safety floor in supervisory logic
Want the rest? Members get every scenario.
• Restore HOA to Auto and VFD to Remote/Auto; return bypass selector to DRIVE after clearing drive faults.
• Clear higher priority slots to Null; confirm program has authority.
• Command → Feedback → Proof: start the fan, watch current rise, verify status closes.
• Remove temporary forces/jumpers; document photos, amps, PA slots cleared, device IDs.
• Retest the original complaint and leave breadcrumbs in the work order.
Worksheet A (Service-Call Intake), Worksheet B (Baseline Snapshot), Worksheet C (Diagnostic Log), Worksheet H (Point-to-Point Checkout). Field Kit §01 control chain and §09 Priority Trap.