Ray Guns Victor VC305B LCD Handheld Non-Contact IR Infrared Thermometer Gun

Hi - We purchased many of these Ray Guns Victor VC305B LCD Handheld Non-Contact IR Infrared Thermometer Gun BUT when I tried to calibrate it against Ice Water & Boiling water it did not read as 0ºC & 100ºC as it should. Do you have calibration instructions?


Low-cost hardware such as this won’t have as many features as the few-hundred-dollar equivalents (such as calibration mode), though they are great for everyday use.

Ice + Boiling water might not be a great way to determine temperature. Ice can get much colder than 0ºC. On the other end of the spectrum, water turns to steam at 100ºC (though is instantly cooling the moment it mixes with atmosphere). I’d imagine there would be a mix of light energy bouncing back from steam and/or water molecules.

Hi Karen,

In the product manual it mentions the “emissivity” of objects being measured. Since the temperature is measured using infrared light, shiny, polished metal, or reflective surfaces will not give accurate temperature readings and the infrared bounces off. It recommends measuring from dull surfaces. If needed put a piece of tape on the object being measured, or apply a thin coat of black paint.

Water would be highly reflective and difficult for this device to measure.

Hi Guys

Thanks for your comments, they do make sense to me, I will try to reducing the emissivity.

The Ray Guns are being used to measure temperature of Cooked Food, chillers & freezer temperatures in the Food Industry. As part of the requirements we have to calibrate temperature reading devices to ensure they are accurate.

Stephen - you mention the “Product Manual”, where do I find this?

I think he would be referring to the chart

here https://core-electronics.com.au/victor-vc305b-lcd-handheld-non-contact-ir-infrared-thermometer-gun.html

Hi Karen,

I’m referring to the product manual: https://www.lion.co.il/site/HvDest/VC303B.pdf
This is the manual for the 303B, it’s essentially the same but with a smaller operational range. The manual for the 305B is only available in Chinese but if you compare the two they very likely say the same things.

Certainly the parts about emissivity would apply equally to both models though!

Sorry for the confusion! Hopefully that helps clear things up!

WOW - Stephen

Thanks so much for sending the manual, that will help a lot when we are audited.


Wishing you guys a great day!

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