A.O. Smith 110-310-510 – ERROR CODE 510[510 (T-D2)], SIX FLASHES/51 [110 (T-KJR2), 310 (T-K4)] ABNORMAL GAS VALVES


Driving circuit fault for the main or solenoid gas valves.

1) If the hot water is shut off, but flames are still visible through the sight glass, immediately shut off gas and power to the unit and contact the Technical Service Department.
2) Check the wire connections to the gas valve assembly for burns or cuts.
3) If the unit was recently rebuilt, make sure that each gas valve wire is plugged into the proper place.
4) Verify that the supply gas pressure is within the specified limits. Too high of an inlet gas pressure may cause the main gas valve to jam or could be damaged.