Performed maintenance on 2 of the 4 systems. The office unit was in a lock out involving the outdoor unit. I rebooted the condenser only and the code cleared. The system is now operational and we will monitor it from the office. There is another system having an issue and it involves the integrity of the flue pipe. We need to return to address to make minor repairs to flue pipe. The only systems needing maintenance are the mini split and the system that is shut down.