Atwood water heater problem

When you replaced the Board, you got a set of clean edge contacts. What about the multi-contact connector that slips onto it? With power OFF, look at the contacts and see if they're all "springy." Just thinking you might not be getting full functionality. Probably a long shot, but I know the connector causes problems with Atwood water heaters not lighting. Don't know if it can cause your specific issue.

Make sure the small round flame spreader has not broken off the end of the burner. This happens fairly often, and the lp doesn't really hit the electrodes then.

Excuse me I replaced the circuit board not the beaker. That's when I got the spark back. Will try replacing electrode and let you know. Thank you so much for your help.

Circuit breaker has nothing to do with spark/ignition on that water heater.
Circuit breaker would be for 120V AC---electric element if you have a combo water heater

Spark/ignition/propane flow are all 12V DC

IF you have SPARK and if you have GAS FLOW but no ignition:
1)Poor electrical ground....Green wire above T&P and Black wire behind gas valve
2)Electrode assembly mounting screw...provides ground and if electrode is sparking to it then no ignition ---adjust electrode
3)Dirty electrode......clean with emery cloth
4)Electrode NOT engulfed in main flame...should glow red
5)Flame spreader on end of burner tube not 'square' with tube..gas doesn't spared out correctly and spark can't light it

IF main flame is good strong and blue when you light it off with BBQ lighter then:
Good 12V DC voltage supply..........good grounds.....correct placement of a clean electrode should resolve issue