199M with ssu-60 indirect water heater, two Heat Controller fan coils, glycol system 30%, concentric venting 8 feet above ground on 2 story wall. From reading all the previous posts, I seem to be extremely fortunate on two fronts. Proper installation and venting. No annual maintenance since it was installed 7 years ago (to my shame). The control card just failed, where the relays clicked on and off continuously in one second intervals. Replaced it with a 926 card but noticed the post purge of over a minute seems to cool the boiler output water by 10 F. from when the burner shuts off. Can the post purge be shortened ??? so as not to waste too much heat. The local distributor doesn't keep spare parts so it was going to take over 5 days to get the control card. Fortunately, the winter has been mild here and I was able to get one online from the US within 3 days. During those three days I cleaned the hx and unplugged the condensate drain. Fortunately the boiler was slightly tilted to the back to the drain so only the bottom third of the rear ceramic target wall was water damaged, dropped from the threaded stud but leaning against the rear boiler wall. The washer and nut was buried in the ceramic material. I replaced the rear ceramic target wall but am worried washer and nut will loosen off again. With annual maintenance, this may not be an issue. The drain was plugged solid with coffee ground type material a couple inches above the trap. It would slowly drip but was able to squeeze and tilt the trap downward where after 15 minutes of working it, the rinse water in the hx finally pushed the material out. Rinsed the hx with fresh water from a small pressure hose and was able to flush out all the solids. (7 years worth). It took a few sessions with CLR and nylon brush to clean the hx. But after two days it looks good as new. I cleaned the dust off the burner, cleaned the flame sense probe and ignitor probe. Noticed the burner gasket was slightly loose and will replace it shortly. Should I replace the probes as well, for peace of mind??? The outside sensor failed 5 years ago and was replaced. So in summary, I am very satisfied that the boiler worked fine without any annual maintenance for 7 years but I am very dissatisfied with lack of spare parts in a timely manner. Therefore, the neutral rating. Since the boiler has been manufacture discontinued in 2011, how long will spare parts be available?? Are any components being used in new boilers?? Any further suggestions on what spare parts I should buy and replace based on the 7 year track record?? What is the failure rate of burners, gas valves and blower motors after 7 years? Any other advice would be greatly appreciated. Thanks for all the previous posts. I will keep this boiler and properly maintain it. I would never have guessed that the installation and maintenance of these condensing boilers would be so critical. But that's progress, where the consumers have more due diligence to shoulder. Hopefully, that doesn't sound too bitter.