The 120 Heat Element needs replaced. IF it is bad. The usual fix is to replace the fuse on the Board and restart on 120 and let run for a few days. A Defective Heat Element sometimes will work and once it gets hot and has run for a few days, shorts out again. Some will have the short and will blow the fuse immediately when powered up. In your case, replace the fuse on the board. IF it blows again replace the Heat Element. 120 Elements either work or they do not, they do not work "partially". IF the AC current is too low it will show that code. You need to get a true reading of the actual 120 AC voltage and should NOT be below 108 volts. Doug