As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SEA FLIGHT NR 2160 ON TAXI OUT, HAD TO PULL OVER TO WAIT OUT AN ATC DELAY, WITHIN MINUTES AFTER START, NR 2 FUEL TEMP WENT INTO THE RED. MAINTENANCE CONTROL AGREED TO RETURN TO GATE. MAINTENANCE REPLACED THE NR 2 FUEL HEATER THERMAL ELEMENT IAW QX MTC 9730002. OPERATIOONAL CHECK GOOD. AIRCRAFT RETURNED TO SERVICE.