Does the heater fire up at all? If the igniter is ticking that means that it is trying to fire. The problem can be as simple as a clogged pilot orifice. Otherwise the gas valve may not be opening due to a bad wire telling it to open, or the gas valve has failed.


Also, double check that the gas cutoff valves at the gas meter and the one next to the heater are open, valve handle in line with pipe. Closed, the handle is perpendicular to the pipe. They have been known to shut themselves!