Arrived at location on 7/2/21 Spoke with caterers when I arrived and they told me the noise was coming from inside the box. I heard the noise the last time we were here and it was definitely coming from the condenser, which is when we re-strapped the run capacitor for the compressor. Looked inside evaporator and found ice in the drain pan, the bottom of the coil, and the distributor was a block of ice. Thawed everything with hot water. Ran five gallons of hot water down the drain to make sure the drain wasn’t slow or clogged. Went over electrical to make sure there weren’t any loose connections and checked evaporator motors/blades. Returned walk-in back into service and monitored pressures/temperatures. Found box satisfying at exactly 32 degrees. I believe the box set point was too low and when the humidity was high the evaporator wasn’t properly off cycle defrosting, causing the fan blades to strike ice. Adjusted thermostat and monitored operation. System is turning on at 35