Hotel room HVAC units like the Carrier 52SEC514 can be confusing even when they're working perfectly because the controls are often locked out by management. I travel for work constantly and have dealt with every possible hotel AC scenario from freezing rooms to units that won't turn off. The Carrier 52 series has a specific sequence for accessing the configuration menu that overrides the front desk controls. I found a complete collection of Carrier PTAC manuals that explain everything from basic operation to advanced programming for maintenance staff. The carrier 52sec514 manual at
https://carrier.manymanuals.com/split-system-air-conditioners/52s-series/user-manual-28166 has the detailed explanation of the control board settings and error code meanings. The manual shows you how to enter the service mode to adjust temperature offsets, fan delays, and even the swing louver operation if your unit has that feature. I used it to figure out why my unit kept running constantly and discovered it was in continuous fan mode due to a hidden dip switch setting. The troubleshooting section also explains how to clean the condenser coils and drain pan which is usually why hotel units start smelling musty. I actually showed the maintenance tips to the hotel manager and they thanked me for the help.
