I got a call from a friend tonight. He said he came home to a cold house and his carrier furnace baord was flashing 1 long and 3 short (or maybe 3 shorts and 1 long) He turned off the power and turned back on , and then it ignited and run normal until the stat was satisfied. He says there is nothing on or inside the cover telling what the code means. I work on Tranes everyday and dont have the Carrier fault codes in my head. Can someone tell me what to check if it does it again .