When i push the on button the unit makes a clicking noise for about 5 sec and then the display shows error code HF which my manual says is a flame fault failure and to replace the igniter. However, I unscrewed the bracket for igniter and pulled out from under heater. I can clearly see the spark across the electrodes when i push the start button . I verified that gas valve was in open position and also took off the nozzles and cleaned some spider webs out.
Any suggestions on what direction to go now.