Cold junction gauge calibration..

[ccsmith51]

I am getting ready to replace my single EGT and CHT gauges with a dual EGT /CHT Westach meter. When reading the installation instructions, it says that the gauge is calibrated at 75? F for the cold junction, which is where the probe wires connect to the pins on the back of the gauge.

It says that for every degree that the cold junction is above 75? the gauge will read one degree low. Conversely, for for every degree that the the cold junction is below 75? the gauge will read one degree high.

I was not aware of that possible discrepancy, and thought others might not be aware, either. When flying in very cold or hot environments, that might make a noticeable difference in what we see compared to true temps. Probably not an issue with EGT, but perhaps with CHT? I assume all mechanical gauges have this error.

Do glass systems have this issue, or do they have a sensor on the unit that can compensate for ambient temperatures?

[mburch]

Originally Posted by ccsmith51

Do glass systems have this issue, or do they have a sensor on the unit that can compensate for ambient temperatures?

Typically, a modern engine monitor will have automatic cold junction compensation built in. I know the one in my airplane does.

mcb