FTL is a 12-key Sentry controller error message that means “Firing Too Long.” FTL can appear during either heating or cooling segments. FTL means the temperature has stalled.
FTL will appear when the temperature change is slower than 27°F/60°C per hour and the firing time is four hours longer than the current segment was programmed to fire. If FTL appears during a heating segment, it is usually due to a worn or burned out element, defective relay, low voltage, or a defective thermocouple.
If FTL appears during a cooling segment, it is usually because the segment was programmed to cool faster than the kiln’s natural cooling ability. To solve the problem, slow down the cooling rate.
Example: FTL appears during a segment that is programmed to cool from 725°F down to 75°F. The rate is 570°F per hour.
To eliminate the FTL message, try a cooling rate of 100 instead of 570. Or you could remove the segment altogether. The kiln will cool only as fast as its natural cooling ability anyway. So the cooling segment mentioned above serves no purpose.