### 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:
- AHU Running
- OAT < 68 °F
- Economizer Mode = 0
- POK:OAT > 38 °F and OAT < 68 °F
- ARC:OAT > 40 °F and OAT < 68 °F
- RTP:OAT > 40 °F and OAT < 68 °F
- BMT:OAH% between 27 and 55
- AUS: Enthalpy < 24
- Enthalpy < 26 IF Reporting

### How long the conditions were met:
Met for 2 Hours

If you were to advise the operator, which option should they prioritize, based on the conditions?
A. System is in a manual mode
B. CRAC units with the chilled water valve is closed indicates a problem with controls wires from the valve to CRAC unit could be off
C. Filters clogged
D. Check the logic in the BMS to see how it is set up


# Answer

Answer: D. Check the logic in the BMS to see how it is set up

Guidance Rationale: 
 The Air Handling Unit (AHU) is currently running, and the outside air
temperature (OAT) is in the range of 38 °F to 68 °F, a range that typically
qualifies for economizer operation. However, Economizer Mode is reported as 0,
indicating it is not active, despite multiple site-specific logic conditions
(POK, ARC, RTP, BMT, AUS) that all suggest economizer mode should be engaged.
Additionally, the enthalpy is below 26, and in some cases below 24, further
supporting that the outside air is suitable for free cooling.

While option A (System is in a manual mode) could explain why the economizer is not active, it
does not address the underlying issue of why the system is in manual mode in the
first place. Option B (CRAC units with the chilled water valve is closed
indicates a problem with controls wires from the valve to CRAC unit could be
off) is specific to CRAC units and chilled water valves, which may not be
relevant to the AHU's economizer function. Option C (Filters clogged) is a
common maintenance issue but does not directly relate to the economizer mode not
being engaged. Therefore, the most likely cause is a configuration or control
logic issue within the Building Management System (BMS), making option D (Check
the logic in the BMS to see how it is set up) the most appropriate action to
prioritize.