Abstract: A system is provided for detecting a seal fault in units which include sealed gaseous portions. The system includes an electro-negative tracer gas inserter for inserting an electro-negative tracer gas within the sealed portion of the unit, a gas sampler for sampling a flow of gas proximate the object containing the tracer gas and an electron capture detector connected to the gas sampler for monitoring the gas for the presence of the electro-negative test gas. The system thereby determines a presence or absence of the seal fault in the sealed portion of the unit.