Quick question about probe verification.
I would like to purchase a reference probe for the company and verify weekly temperatures with boiling and hot water comparing it to reference probe. Are there any requirements for a ref probe to be fulfilled (except the obvious that it must be calibrated and certified)?
Also, if we do verify the freezers temperatures with probes, what would be the temperature check to reaach the scope? freezer is approximately -18 and boiling water only 0. how to challenge the -18 temperature?
Actually the probe is only half the unit.
You omitted to mention what kind of thermometer you are purchasing.
The choice may also relate to yr intended usage / desired accuracy. I invested in one relatively expensive unit which I reserved as a "master" for internally "certifying" other "sub-master" units.
afaik most units are pre-calibrated/documented at melting ice temperature,
IMEX, for thermocouples, the accuracy across the range 0-100degC can depend on the cost. A unit with a resettable zero may be worthwhile
IMEX. measurements at ca -18degC will likely require having the unit separately certified at that temperature. (I attempted to prepare suitable reference solutions but ultimately concluded too much trouble). Professional calibration at specific temperatures is often not particularly expensive.
I personally found that using steam was operationally more reliable than boiling water. Just my opinion.