i have a Weil-Mclain ultra series 2. It has the cast aluminum heat exchanger. It was installed when my home was built 12yrs ago. I have infloor hydronic heat. The boiler has been a fair amount of trouble. The fan was replaced under warranty 3yrs into its life. A tune up kit and cleaning of the heat exchanger was done last year. And every year...About 3 weeks ago I was giving me the fail too Ighnite code, so I replaced the Ighniter. Runs for a while a d says same error code. The aluminum heat exchanger gets a lot of black gritty stuff in water condensation drain tube but when I was serviced a ton more came out, seems odd that that much stuff would be junking up the guts of the boiler. Can a aftermarket stainless exchanger be put in place or not worth it. 3 weeks of no heat. A service tech has also tried increasing the amount of gas let in on the valve. No luck. Do I need a new boiler?