Thermocouple Testing?

[John-Peterson]

I used my heatermeter today and had a weird temp issue. I ran to the store and when I came back the dome was at 375 and the probe, which is clipped to the thermometer, was at 135. When I disconnected it and left it outside, it was reading the air temp correctly. I know the dome temp was correct. Not sure what happened but I need to test my thermocouple. What’s the best way to do this?

 

[Bryan Mayland]

That does sound like bad readings, that are possibly coming in as noise on the probe's shielding or something. If you're on a recent version (last 6 months or so) when you're logged in to the home screen in the webui, you can press "n" to bring up the noise graph. It should look like this, bouncing around between a two or three values, not a giant mess spanning many values.


You can also try powering the HeaterMeter off a 12V battery if you have one handy to see if the noise goes away, because usually it comes from a ground loop through the power outlet.

 

[John-Peterson]

Hi Bryan,

Thanks for the reply. I believe I am on and older version. The last time I updated was at least a couple years ago. I am on the original hardware with I believe a Pi2 or whatever came with a composite video jack. The alligator clip had a bunch of crude in it from the dome thermometer. I cleaned that out with a tooth pick but still got about the same reading.
I’ll see about updating and check for noise as you suggested.

 

[Bryan Mayland]

The current software is compatible with all HeaterMeters back to 4.0, which was the first that used a Raspberry Pi. Settings should retained through an upgrade but I can't guarantee that 100%, so make a note of your settings before upgrading just in case. That said, the defaults are pretty decent so even starting from a clean SD card isn't too torturous.