E24 - Meaning
Occurs when the thermocouple does not reach its final temperature within 1 minute
Possible reasons:
Aged thermocouple
Thermocouple wire insulation damage and shorting to metal chassis.
Problems with chimney or room air inlets (insufficient air circulation)
Unstable pilot flame (i.e. wind, insufficient thermocouple couple position)
Contaminated pilot, giving poor flame that heat thermocouple (see section on pilot)
Incorrect position of Ceramic parts (i.e. coals, logs or matrix)