Boiler corrosion concerns.

[Mike Lamb]

This is the underside of a cast iron steam boiler. The iron is corroded and rusting. The boiler was shut down for summer. Should this be evaluated further with the boiler running, or not so important? Peerless year 2012.

[Bill Kibbel]

It's not unusual for a steam boiler to fail very, very early.  You usually don't see a leak with a boiler —running hot or standing cold.  You would have to manually flood the boiler to find a leak.  Many leaks are first detected when steam turns to vapor emitting from the chimney flue.  I try to run the heck out of steam boilers, while going outside a few times to see the top of the chimney.  I've found many failures and one of them was only 8 years old.

Almost all of the newer boilers failing is mostly due to the near-boiler piping being incorrectly installed.  The piping has to be specifically configured to compensate for being so much smaller than the old steamers.  See: https://historicbldgs.com/steam_heat.html

Yes, the boiler needs to be checked out for possible failure.  It could be helpful if you can show us a pic of the piping. 

[Mike Lamb]

Thanks, Bill. No good pictures of the piping but your link on boilers is enlightening.

[Rob Amaral]

Back in 2007-8, during the 'loan crisis', I'd see hydronic cast iron sectional boilers that 'sat' with no pilot/heat for many months literally rust-themselves-apart and leak at the sections due to sitting cold in summer and sweating (with water in them)....  In-use boilers, especially those that double as DHW heat-source tend to 'make it' very well.. .just a thought.. .