Below is a blog post that Gennady responded to recently regarding how important maintenance is for boilers.

https://forum.heatinghelp.com/discussion/185121/my-clients-heat-exchanger-got-blowed-up#lastest

Original poster - heat exchanger blew up:

It even blew the bolt heads off. We found it like this during a recent heavy rain. The flue was full of water. The condensate neutralizer was draining too slowly. I think they should rewrite the manuals to show flue piping terminating with one-two 90s. Many show a straight-up, open termination.

Gennady’s response:

I think the boiler was working for a while with a compromised gasket and/or studs.

We caught a similar problem on 2 million BTHU boilers during maintenance, done for the first time in 10 years after installation. Lucky client, these heat exchanger covers were about to fall off.