My hot water heater John Wood installed in 2008 ,was flame out yesterday. I try to relite the pilot light many time but failed. The ignitor sparks are good but no gas flow out from the pilot gas line. I checked the TCO switches and they all closed , changed new thermalcoupling too . I didnot hear any sound of gas flow throught the pilot gas line when I depress the pilot button on the White Rogers gas control valve. Some thing wrong with the gas control valve ?? Thanks !!