Calibrating pyrometers

G

grizzled gizzard

Joined
Aug 31, 2010
Messages
726
I got an Omega HH503 a while back, and I think it's out of whack. :D

Has anyone ever (for instance) drilled a hole through their Evenheat door, just large enough to get the probe through, to double check things?

You gentlemen probably have better solutions. I need one.

Thanks
 
So, you think your Omega is off and your Evenheat is ok? How much do you think it is off? Do you have it set for the proper TC type? Connections good, battery fresh?

At work we use a third party calibrated "calibrator". It is plugged into the pyrometer/controller TC socket: you set it for TC type and temperature. The calibrator sends a signal equal to what a "perfect" TC would deliver at that temperature - if the unit in question is indeed off then you reprogram it with offsets.

If the unit is proven good then you can test the TC. Use boiling distilled water and its boiling temperature at your elevation as your "standard" for the low end (for oven applications) temperature.
 
I'm pretty sure I have my pyrometer set correctly. Both units are new. When I first got the pyrometer, I measured my burner heat in the forge, and with a reducing flame it was in the 2100 range. I checked it again a few days later, and I wasn't getting near that hot. After I had run the oven up for some blades, I snuck the probe into the forge, and onto the sensor in the oven. After a while, when I thought things should be acclimated, the pyrometer was about 210 degrees lower at around the 800* mark. I kept the pparts together, and as they cooled down, the readings got closer, but by the time the oven hit 400, the pyrometer said about 270.
 
Recheck the setting for TC type, ie, K vs J. If the TC has screw type connectors (either in a removable connector or terminal block) make sure they are tight and there is good contact. Did you kink the TC wire? They are not stranded wire and will break. Are there extension wires on the TC now that weren't originally there? Make sure they are the same material type as the TC. Any of these things will screw you: mixing wire types creates additional voltage and changes the signal. Damaged wires/loose connections add resistance and create a voltage drop and change the signal. Not matching unit setting to TC type means that the offsets and measurement ratio are wrong.

Then again, the unit might have just pooped the bed.
 
Put the couple in the boiling water and you will se how much it is off. Don't forget to correct to your altitude.
 
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