Upon arrival tech found system not running when set in cool mode. Tech found no voltage between Y wire and common at unit. Tech jumped out Y circuit and blew red cap fuse. Short was not big enough to cause thermostat to go blank but only reset. Tech replaced Y wire with Orange and tested. System would only come in when jumped out from outside or at thermostat. Tech replaced Trane XL824 thermostat with Focus Pro 5000 Honeywell and system came on with no challenges, back up and cooling. Will need to come back and replace with new Trane XL824 thermostat. Tech also found W1 and W2 wired in wrongs spots at t stat. No charge per customer satisfaction, system was just installed.