Truth is in the Details ™

The Case of the Cool Cabin

Synopsis:
Ben Franklin’s “A penny saved is a penny earned” needs to be tempered with Pliny the Elder’s “taken with a grain of salt”. In this case a furnace was falsely accused of failure with disastrous results.

Background:
A lake cabin in a northern climate had been unoccupied for six weeks when the owner arrived for a mid-winter stay. The cabin was found encased in ice up to three feet thick in places.
 

 

 

 

 

 

Analysis:
TI was requested to determine the cause of the damage. The $600k cabin was a total loss and the owner blamed the damage on a malfunctioning furnace. Upon investigation, TI found that the cabin was heated with a high efficiency propane-fired furnace which sent exhaust gas to the outside through PVC pipe which exited the cabin at ground level. While searching the base of the glacier in the area where the PVC exited the cabin, a small opening in the ice was found which was an open passage back to the end of the PVC pipe. The absence of furnace fault codes and the exhaust passage demonstrated that the furnace had been continuously in operation during glaciation. Further, the interior of the first floor was ice free while the water that flowed out into a screen porch quickly froze.
 

Next, TI analyzed the heating system and layout of water pipes in the cabin. The thermostat was located centrally in the first floor and thus was in the warmest part of the cabin. Upon investigation of the plumbing layout, there were second story water pipes located behind a knee wall in a bathroom whose ceiling was pitched parallel to the roof. The burst pipes were located behind the knee wall. It was found that the thermostat was set to 40°F, its lowest setting, and that the low temperature alarm setting on the cabin’s security system was set at 36°F. During an interview, the owner admitted that the low thermostat and security system settings were in order to save propane cost. TI’s conclusion was that the furnace had operated continually through the loss event and kept the first floor thermostat satisfied and the first floor ice free. TI also found that the location of the second floor plumbing was such that, with the thermostat set at minimum on the first floor, the pipes located behind the knee wall on the second floor readily froze and burst. TI conclusively showed that the loss was due to a combination of isolation of water pipes behind the knee wall and the owner’s failure to properly maintain sufficient heat within the cabin. Subrogation against the furnace manufacturer was not pursued.

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