Installed 3 ½-ton Carrier gas system. Installed 2 Ecobee thermostats. Installed new supply plenum and zoning dampers. Installed new zone board. Installed a plywood overlay. Sealed all connections with mastic air lock. Installed SS2 safety switch. Built and insulated primary drain line. Cleared drain and verified operation. Replaced outdoor condenser pad. Ran both high and low voltage in protective Seal-Tite. Replaced breaker to match system specification. Pressure tested and pulled a vacuum on the copper line set. Weighed in refrigerant to meet specifications.