Tech assured the power was off to the carrier systems due to renovation. Symbio system - found compressor 2 proving and compressor contactor 1 failure faults. Tech acknowledged the faults and tested the system from the app and operated compressor 1 for 10 seconds and then shut off due to contactor failure fault. Compressor 2 was operating only. Faults were acknowledged and checked pressure switches and Discharge temperature sensor and checked good. Pressures were good when compressor 1 was bypassed for testing purposes. Compressor contactor 1 is recommended to be replaced due to the Normally open switch being a challenge at intermittent times. Tech went over the testing process based on Trane website, for proving compressors and it led back to the compressor contactors. Office will be informed of the findings and would need to return with 2 compressor contactors to be safe. Tech acknowledged the faults and had both compressors operating prior to departure and showed the manager on sit