We attended this site to repair broken down MT coldroom. The system had electrical fault and communication faults from diagnosing. The ambient air probe had lost calibration & the live mains in contact was faulty. We replaced probe whilst making adjustments upon live in to control panel. We also established a expansion valve had been located in the wrong place causing problems from vibration of fan motor, but more so system low on charge because flare upon expansion valve was leaking. System decommissioned to return with necessary components for repair.