K Type thermometer accuracy

[Yirg]

Is the accuracy of K Type thermometers dependent on the probes or the display unit? How critical do you think is a calibration option? I just ordered a thermometer without it (that looks great otherwise) and am having second thoughts...

 

[mblanks2]

I work in the HVACR field where the K type thermocouples are used almost daily. We've been told +/- 2*F accuracy from 0*F to 200*F. Then this inaccuracy increases as the temperature rises. i.e. @ 400*F (+/- 2.9*F)

 

[Yirg]

+/- 2*F would be perfect, but I assume it's not dependent on the connector standard (K Type or otherwise), but rather on the quality of the probe and/or the display unit. Any thoughts on that?

 

[mblanks2]

http://www.priestassociates.com/uploads/How_Accurate_are_those_TCs.pdf

Here's a good read on accuracy and quality in TC's. This might answer your questions further.

 

[Temp81]

The accuracy will be based off the indicating device. The thermocouple really doesn't have a degree of error due to the way it operates. Thermocouples are made of 2 metals or alloys that are fused. When there is a temperature change the metals expand or contract at a specific rate for the type of metal. This difference causes a small voltage to be developed. That voltage is then interpreted by your readout device. In short the thermocouple operates by principles of physics and chemistry, therefore no measurable error.

 

[Yirg]

Thanks, this is exactly what I wanted to know.