### Asset Description:
PIU: A Powered Induction Unit (PIU) is an HVAC terminal installed at the zone level that mixes conditioned primary air from the central system with induced secondary (recirculated) air, using an internal fan and often including a heating coil

### Conditions:
- Parent AHU Running
- Zone Temp > Zone Temp Cooling Setpoint + 4 °F

### How long the conditions were met:
Met for 4 Hours

Review the listed conditions and identify which option MOST accurately accounts for them.
A. Thermostat out of calibration
B. Chilled water valve could be stuck closed or stuck open or stuck some where in between
C. Too many CRAC units are running for the amount of load
D. Vanes at wrong angle


# Answer

Answer: A. Thermostat out of calibration

Guidance Rationale: 
The Powered Induction Unit (PIU) is designed to maintain
zone comfort by mixing conditioned primary air with recirculated secondary air,
using internal controls that typically respond to thermostat input. In this
case, the parent AHU is running, but the zone temperature has remained more than
4 °F above the cooling setpoint for a sustained period of 4 hours. This
prolonged deviation suggests that the system is not effectively responding to
the cooling demand in the zone. 

While a stuck chilled water valve (Option B) could affect cooling, it would likely cause a 
more immediate and drastic temperature change rather than a sustained deviation. Too many CRAC units
running (Option C) would typically result in overcooling rather than
undercooling. Vanes at the wrong angle (Option D) might affect airflow but would
not explain the consistent temperature deviation over such a long period. The
most plausible explanation is that the thermostat is out of calibration,
resulting in inaccurate zone temperature readings and ineffective control
responses from the PIU or associated actuators. Therefore, the most accurate
explanation for the observed behavior is: "Thermostat out of calibration."