I installed a new commercial HVAC system for a retail store. The system included a York 10-ton rooftop unit with a variable-speed compressor. I mounted the unit on the roof, connected the ductwork, and wired the control systems. I also installed a programmable Honeywell thermostat to improve energy efficiency. After installation, I charged the system with R-410A refrigerant and calibrated the thermostat. I ran multiple tests to ensure even cooling throughout the store, and verified the zoning system was functioning properly. The new system is now providing reliable heating and cooling for the business.