Heating Help

Anybody see a boiler do this sitting idle?

This boiler decided to crack in two. Sitting off in 90 degree weather. One hundred and fourteen thousand gallon of water went into the basement.
   Any ideas what would cause it?

mysterious boiler failure

could this boiler have a hot water coil, and be in a building infrequently occupied? maybe the boiler was turned off, and leaked dry with a malfunctioning LWCO. when the owners came in the summer, and wanted hot water; turned on the boiler, and it dry-fired.--nbc

Not dry

This boiler was in a three story apartment building with separate water heaters. A 114 thousand gallons of water filled the basement. I know cold water was coming back to it. But you would think that would cause it to break while it was running.

Thermal shock

The boiler may have been subjected to thermal shock.  If the cracked section was on the end where the return was connected, I'd bet on it. Make sure the next boiler has either a Thermic valve or bypass with thermometers so that no thermal shock can occur.

Thermal shock

Do you think that the cold water coming back created micro cracks and it just decided to let go sitting there.
    The new one has a thermostatic valve and primary/secondary pumping.

Water still up in the system

When it was discovered the owner turned the water main off. I had him close the system valves. When I went in it took well over 2 hours for the system to drain down. We broke the section up there didn't appear to be any discoloring or scale to indicate uneven heating from the inside. It did have a lot of coating on the fireside from soot sticks. When i first worked on this boiler someone had put a full box of soot sticks inside the chamber. I had to use a drill to get the sections open. Uneven heating and cold return water probably stressed it. But you would think it would have broke during a stress period.
    Mark

Is that a Peerless?

I've installed hundreds of them. Taken out quite a few too. Never saw it crack like that when being used for hot water. Even with steam its a hard boiler to crack. How do you know how many gallons dumped out? Was there a meter on it? Was all that system water?

Pressure

Replace one in an apartment building 6 years ago where someone had replaced the weeping relief valve with a 75# relief. It also failed during the summer. Perhaps the relief was blocked and the expansion tank was waterlogged?

Clue

I believe from the fuzzy pictures that your answer may be in the color of the metal.
It may have been cracked and weeping for years. The inside of the crack surface should indicate that.
Metal can be installed under stress, pressure and torque on bolts and pipes will created expansion and contraction over time, eventually molecular bond fails and snap, tension is relieved and all stress is transfered from the metal to the owner to deal with. Tension can even start in the casting and uneven curing of the metal.