Detector Problems:

Within the event which key temperature sensing instruments become inoperative, there are various alternate methods which might be used. A few applications utilize installed spare temperature detectors or dual-element RTDs. A dual-element RTD has two sensing elements of that only one is generally linked.  The second element might be used to gives temperature indication if the operating element becomes faulty.  A contact pyrometer (portable thermocouple) might be used to obtain temperature readings on those pieces of equipment or systems that are accessible if an installed spare is not utilized.

If the malfunction is in the circuitry and the detector itself is still functional, it might be possible to acquire temperatures through connecting an external bridge circuit to the detector. Resistance readings might then be taken and a corresponding temperature obtained from the detector calibration curves.