Arrived at location on 12/5/22 - Spoke to owner about issue and says pizza is not cooking correctly and he gets a reading of under 500 when set to 550 degrees. Checked manual for unit for a calibration and could not located it. Called middleby about issue. Did troubleshoot with tech support. Found thermocouple giving lower millivolts then needed. Will order a new thermocouple assembly for the unit. Will return. Returned to location on 12/19/22 - Top oven. Removed panels. Removed old temp thermocouple and installed new. Reassembled. Turned on blower and heat. Let heat to set temp of 550°. Temp is stable and not fluctuating. John said he’s not gonna run anything through until later and will let us know if there is still a problem. Back in service.