Diagnosis
Using Process of Elimination for Intermittent Faults
Intermittent faults, where an appliance works normally most of the time but fails unpredictably, are among the most challenging to diagnose because the fault may not be present during the actual inspection visit. A structured process of elimination approach helps in these cases, starting by gathering detailed information about the conditions surrounding each occurrence, such as time of day, weather conditions, or whether other appliances were running simultaneously, looking for a pattern that might not be obvious from a single incident description alone. Checking components known to be sensitive to specific triggers, such as testing capacitor values under simulated load conditions or monitoring voltage during peak electrical demand periods when the fault is reported to occur more often, can sometimes reproduce the fault under controlled conditions rather than waiting for it to occur naturally.
Data logging devices, which record electrical readings like voltage and current over an extended period, can capture conditions at the exact moment a fault occurs even when no technician is present, providing objective evidence rather than relying solely on the customer's recollection of symptoms. When a suspected component tests normal under standard conditions but the fault continues to recur, considering less common causes, such as a marginal connection that only fails under specific thermal expansion conditions, becomes necessary rather than repeatedly retesting the same obvious suspects.
