### Asset Description:
AHU: Air Handling Unit: A device used to condition and circulate air as part of a heating, ventilating, and air-conditioning (HVAC) system.

### Conditions:
- Supply Fan Status = 1
- Subtype NOT MULTI or VAV
- Duct Static Pressure < 0.01 inH2O
- Air Flow < 100 CFM IF Reporting

### How long the conditions were met:
Met for 3 Hours

What underlying factor, as presented in the options, could explain the current asset state?
A. Relay from BMS to fan is broken
B. Check the command from the BMS
C. Dehumidification flow issue
D. Is the system overridden


# Answer

Answer: A. Relay from BMS to fan is broken

Guidance Rationale: 
 The Air Handling Unit (AHU) has a supply fan status of 1, indicating that the
fan is expected to be actively running. However, both the duct static pressure
is extremely low (below 0.01 inH₂O), and the airflow is under 100 CFM,
suggesting that no significant air movement is occurring. Given that the AHU
subtype is not MULTI or VAV, this behavior cannot be attributed to variable air
strategies. The discrepancy between the commanded status (on) and the actual
airflow behavior strongly points to a failure in the relay or communication path
between the Building Management System (BMS) and the fan hardware. 

Option A, "Relay from BMS to fan is broken," directly addresses this issue. Option B,
"Check the command from the BMS," is less likely because the fan status
indicates that the command is being sent correctly. Option C, "Dehumidification
flow issue," is irrelevant as the problem is with airflow, not humidity control.
Option D, "Is the system overridden," is unlikely because an override would
typically result in the fan status reflecting the override state. Since this
condition has been persisting for 3 hours, a transient control issue is
unlikely—indicating a hardware-level problem, such as a broken relay. Therefore,
the most likely explanation is: "Relay from BMS to fan is broken."