Raypak pool heater restarting

[21inguns]

My raypak 336 digital heater, was having issue with high limit switch 1, (unitherm governor is relatively new also is the bypass spring) when I checked the switch was faulty and corrosion on it. I easily installed a new high limit switch (well replaced both to be safe ) but after I restored power and turned unit on, it started restarting the unit. And not like a fire up run for a moment shut down with a code. When I turn it on, it will do normal startup on screen. Show pool water temp, then the set temp, I hear the click for the pilot light to start and the little fire symbol will display for a second, then the display will reset and do the whole thing again. As if I turned the power switch off and back on. If i quickly lower the set temp to below the water temp the display stays on, but the moment I raise it just 1 degree above, it started the cycle... hear the click see the flame then off and back on. It will do this non stop. Has anyone experienced this? Should I assume faulty board?