We had an incident Monday that I thought might be worthy to post. One of our customers owns a large retail store. This past Sunday evening the local fire department began receiving calls overnight Sunday to Monday morning, reporting the smell of something burning in the area around the store. The fire department responded a number of times but could not locate the source of the smell. Around 8:30 AM Monday morning more calls were received and during the search the fire department went to the store's basement motor room which contained 3 hydraulic elevators. When they opened the door they were hit with a blast of heat, and immediately shutdown the elevator circuit breakers. One of the elevator tanks containing 150 gallons of oil was literally boiling. 3 hours later when our technician lifted the lid on the tank he had the use a piece of wood because the tank was still so hot you could not touch it.(See attached pics, at this point 3 hours after the unit was shut down the oil was still boiling, which you can see if you look closely) It had gotten so hot in the tank that the gauge on the valve had melted and the wires to the valve were stiff and brittle. We determined the cause of the problem to be a fused RU contactor, and while the computer generated a fault and took the system off-line, the contractor remained fused closed which caused the unit to continually run, we believe for 10 to 12 hours.
The reason the fire department did not find the source of the smell was that there was virtually no smoke and the machine room vent, which is very large, is located down an inaccessible gated alleyway between 2 large buildings.
There are working smoke and heat detectors along with a sprinkler system in the motor room yet none of these activated. We are still working through our initial investigation but I was wondering if anyone knew of a system that would shunt power based on oil temperature?
This system is relatively new (less than 10 years) yet this still occurred.