Frozen Radiator, Need Help

jackreilly

The caretaker for an older woman who went to a nursing home in the winter of 2013/14 maintained background heat in a house with a closed, gravity feed system. One cast iron radiator, which we assume had an air embolism, froze and ruptured (photo attached).The mean outside temperature during this two-week period remained at 24°F; the outside temperature never reached 32°F. When the background heat was able to thaw the frozen radiator, the house flooded, causing approximately $25,000 in damage. A professional engineer maintains that the vacant house was completely unheated that winter and that once the radiator cracked, the pressure reducer valve opened, forced-out the ice and then flooded the house. The insurance claim was denied on grounds that the homeowner had been negligent in failing to provide any heat in the house.
I would greatly appreciate comments from experts in hot water heating systems who have dealt with houses that froze-up and suffered from ruptured radiators. I would like comment from anyone who has ever heard of a completely unheated house, in which the rupture of one radiator somehow caused flood damage without the radiator thawing out and without the rupturing of multiple radiators in sub-freezing weather.
Photographs will be greatly appreciated. From my experience with investigating 12 houses with frozen radiators over the past 37 years, it is my impression that most frozen radiators will crack at the bottom of the radiator, or near the bottom.
I am a home inspector who has hands-on experience of installing only five residential boilers in my life, but I have also inspected approximately 8000 hydronic systems during my career. For more than 25 years I have had a friendship with a principal of All Steamed Up, a company in Baltimore Maryland that deals exclusively with hydronic systems. When I find myself a little uncertain at analyzing a problem with a hydraulic system, the guys at All Steamed Up are always an invaluable help.
Attached are photos of the cracked radiator and the radiator in the next room that was plumbed the same way but did not fail.
Jack

Jamie Hall

Pity there wasn't an "air embolism" -- had there been, it might not have cracked.

There are many possible failure scenarios here, of course -- but the bottom line is that a) the house at that specific location got cold enough for whatever reason that the radiator froze and cracked and that at some subsequent time b) the temperature in the immediate area rose enough so that the ice melted, or enough of it melted and then c) the water line to the boiler wasn't shut off and when the pressure dropped due to the leak, the water line fed water into the system through the PRV. And kept on feeding until someone noticed it.

The structure does not have to be unheated for this to happen; all that is necessary is that the heat is turned down low enough (or turned off long enough) for that one location to freeze.

And yes, I've seen that happen. Not often, but often enough -- and if the total damage claim is as you say, you got off easy. I know of at least one instance where a half million dollar house was a total loss...

For those reading this -- the bottom line is that if you are going to leave a house vacant, you have two choices: turn the water off and drain all the piping -- all of it, including the heating system -- or have someone reliable check the house at least daily to ensure that everything is as it should be (water leaks, gas leaks, popped circuit breakers, broken windows and so on etc.). If you are trusting a wi-fi device, then be sure that it is fail alarm; that is, if anything goes wrong including a glitched wi-fi signal, it sends an alarm and someone checks it out.

JUGHNE

Proof that the heat was on might be shown with the gas bills or oil consumption for that time period.

Granted that maintaining low temps would use less fuel than when she lived there, but should show that some heat/fuel was being used. You could compare HDD fuel consumption from previous seasons and allow for lower set temps.

It should show that the statement of "completely unheated" would be false. Also how did the ice thaw as Hat states.
A completely unheated house might not warm up for a long time. Once that cold, it stays cold a long time waiting for solar gain to reheat it.