Found the system with burnt wires, blower relay smoked/failed, abnormal low voltage wiring (2 transformers wire in together on the low voltage side) and thermostat wire cut off due to recent floor work performed. Tech received approval from the homeowner to perform todays repairs.tech ran thermostat wire from the thermostat base to the furnace, corrected the wiring and replaced all the burnt high voltage terminals at the furnace. Costumer also invested into MPA (monthly premium agreement). Tech tested the system afterwards in cool and system operated without challenges. Mercury thermostat is encouraged to be replaced/upgraded. Tech also found 2 10inch crossover ducts (one measures 15-20 feet and the mother one measured 25 feet) in bad conditions. Costumer is aware and will consider to replace them when they are ready to replace the whole hvac system. Outdoor unit capacitor is rusted but was reading good(within specs). System is back cooling but will lack of airflow.