Water heater igniter continuously attempts to light after burner lit

[Hendrick2448]

I have an American 50 gallon Nat Gas water heater that is about 11 years old. It heats well and does not leak, but recently it started making a noise that I identified as the igniter trying to light after the burner flame is already lit and heating. So when I use hot water, the igniter lights the burner, I have good flame immediately but the igniter continues to attempt to light rapidly in succession, perhaps 5-10 times in a few seconds making a fairly loud clicking sound, then will stop for a random interval before attempting to light again, despite the flame being present and the flame sensor in contact with the flame. I removed the flame sensor and cleaned with steel wool, it was not in bad shape to start with but worth a try, did not resolve the issue.

Anyone experience this sort of issue / know how to resolve? Or should I just replace the whole unit as it is getting towards the end of its service life?

Any advice is appreciate, thanks!

 

[breplum]

I don't know the model you have, but more than a few times on gas furnaces, the flame sensor rod needed more than steel wool before starting to behave again.
Back edge of a pocket knife or back edge of a wood chisel to scrape oxidation away.
For sure, time to seriously considering replacing the WH is anode rod was not replaced at intervals appropriate.