Lewis K. Redmond of Plainfield, Illinois, asks:
"We have an Adler/Barbour cold machine refrigerator, which is air-cooled with a small vertical evaporator. The ground wire and its retaining screw on the PCB board somehow were burned black. The technician’s guess was that something must have been thrown across the terminals to have caused this burnout. What measures would you suggest to prevent this from happening again?
Any other ideas on what might have caused this ground wire and retaining screw to be burned black? The 15-amp circuit breaker on AC panel at the dock never tripped. I’m fairly sure this did not occur while sailing, but rather at the dock. Would an ELCI/RCBO device have prevented this short and damage?"
Nigel Calder replies:
Michael Adler, the founder of Adler Barbour, tells me there have been too many changes over the years in basic compressor design and operating systems, plus many changes in the control electronics designs and functions, to give a definitive answer as to what went wrong. However, the problem could have been caused by an internally shorted compressor winding. Michael suspects the external electronics are also fried.
He suggests: A) checking the entire electrical harness with reference to the manual and schematic originally supplied; B) measuring the pin-to-pin compressor resistances per the manual’s trouble-shooting section to see if the compressor has failed; and C) replacing the electronic component, usually called the “module.”
An ELCI likely would not have prevented this damage. An ELCI measures small imbalances in the incoming hot and neutral lines, and trips the circuit if these occur. If it is the compressor that has failed, there will be no imbalance in the AC feed to the electronic module that runs the compressor, as the problem is on “the other side” of this module.