I finally pulled the heat exchanger and had it repaired by a reputable radiator shop. I replaced the spring, rod, round plastic piece, and bolt that held rod in place. Reassembled everything.
When i turn the heater on thru the digital display I hear the "whoosh" and feel the heat radiating thru the top. Within 10 seconds or so I can hear the flame go out, water gurgling in the pipes in the heater. Then it lites up again this time not as forceful as the initial light up, heat comes from unit and within about 5 seconds shutsdown and relights in about seconds, repeatedly doing this. A error code doesn't show up in the display. I let it cycle like this for a minute or 2 hoping something will change on the next ignition but it doesn't.
Could there be something in the heater coil that is damaged that I cant see? Did I not install those replacement parts correctly? seemed straight forward. Did something occur from the heater it sat up for quite awhile? Could water in the gas line cause this?
Thanks for any input.