Well assuming thermocouple. Ancient small kiln with simple T/C feeding analogue ammeter. Ammeter seems ok , 1.6mA reads 600 deg C on the scale,
2.7mA reads 900 degC. The original T/C broke at the weld. Control of the heater is just by timer. Got some new T/Cs which seem to work ok in themselves, rising to about 8mV on DVM-V for 300 deg C hot air. But try them with the ammeter and no observable movement of the needle, either way round . The metal of the conductors on the original is much larger diameter of 1.5mm each, than the new ones both contained within 1.5mm stainless sheath, that type is Nc/Na, not matching original type? which would have been ? Original has different patination on each conductor so dissimilar metal is as far as I know. The ammeter, should anyone have any info is HOYT D4735P-1 measuring about 10.3 ohms across the terminals with nothing connected to it. Furnace is Jelenco or Jelrus, New Hyde Park, model LFC or LFCSP- posted
9 years ago