Here's a challenge for any Plumber, HVAC tech, Scientist, Physicist, Forensic Investigator, or anyone here with some kind of idea as to what happened -- I'm racking my brain, can't sleep trying to figure it out, and I'm getting nowhere.
The Scene: a 1930's, 2-bedroom, 2-story house with basement, in Northeastern Ohio. Heating System: hot-water heat and radiators by gravity feeding (no pump is involved), automatic water filling, and what I believe to be an "expansion tank". The residence is occupied sporadically by a close family member. Temperature setting: 55F while away.
The family member returned to the house after a cold snap (sub-zero temps). The whole house was freezing cold, and nearly every surface had a layer of ice on it: walls, windows, doors mirrors, inside closets, and mostly in the basement (icicles where all over the place in this area).
The hot water boiler had failed at some point and clearly vented a large amount of steam into the house. It looks like it started at or near the boiler unit (it was converted from a coal-fired system, to natural gas in the 50's). The water bill reflects a large amount of water used in roughly 2-weeks.
The Mystery: 2 of the 7 cast iron radiators had a chunk blown out of the side...
These things weigh a LOT, and are as strong as they are heavy. You couldn't do that with a sledgehammer.
This is the part that has me stumped. Even the plumber and HVAC guy (an old-timer in the biz) said that they had never seen or heard of anything like it -- both the radiator blow-out, and the steam-to-ice incident.
Investigation: I visited the place tonight. The clean-up crew and sub-contractors had installed a high-efficiency, forced-air (natural gas) burner, and placed a temporary duct into the basement. Future vent holes have been cut in the floor to let the heat rise, and thaw the ice. "Moldy" is an understatement. Even light fixtures in closets were dripping wet. All the carpet had to be removed (it was crunchy with ice when first found).
Theory: The boiler cracked (perhaps the exansion tank) and expelled a large amount of steam and hot water into the basement. As it rose, the steam permeated every room, closet, and the attic. The system compensated by adding more water to the system and kept the steam process going until...
The point at which the boiler failed entirely is a mystery. It's a simple system of "open gravity flow", heat, and water. It completely quit, and froze-up the house.
How did the radiator burst? The weakest point is a small valve to bleed air from the line, at the top of each rad. What blew, was the opposite side, at the top.
Could excessive line pressure do it and force more steam into each of the 2 rooms? Did the water not return after failure and it turned to solid ice, expanded, and ruptured the iron? If the expansion tank fails, the system fills with steam instead of water, does not have adequate return and calls for the feed line to provide fresh water. What prompted the system to quit? Perhaps the steam damaged the thermostat, or the circuit to engage the system. The pilot light could have extinguished, forcing a shut-off of gas via thermocouple
3rd Party Testimony: No solid ice was reported in the radiators. The boiler was dismantled and recycled -- no report on its condition, other than "covered in ice". It had to be removed to install a temporary furnace until the replacement was installed -- to begin the thawing process. The house is nearly thawed, and will be de-humidified, and repaired. In the meantime plumbing and electrical components are being replaced.
I can't seem to get a straight theory out of anyone. All they know is that the boiler cracked (or component), the house was steamed-up, the heating system failed, the condensed steam turned to ice, and the place was wrecked.
Luckily I moved a bulk of antiques and family heirlooms back to KC last summer. That was a task! But it's sad to see the place in such a state. I always remembered it as very well maintained and organized.
So, that's the mystery. The biggest things I'm trying to figure is 1) how the heck did a solid piece of cast iron bust 2) what exactly failed and spewed steam; and 3) at what point did the boiler say, "Enough is enough"?
RH77