Digitech QM7221

Inaccuarte readings – While teh concept is great the temperatures are 10% low with no capability of calibration. Not recommended like too any other Digitech products I have unfortunately purchased. No backup so not a brand I would recommend

Inaccurate – It was working well on day 1, on day 2 there were some inaccuracies. tested it by shaved ice in a little bit of water, was 9 degs out. Rubbish. Now i have to return it. waste of time..

Sensitivity to shiny surfaces makes it less useful than it appears – I bought a QM7221 to use for a number of jobs, and have mixed feelings about it. It is easy to use, the twin targeting "lasers" (assuming, as I have done, that they are accurate!) make it simple to see where you are measuring. Depending on the degree of accuracy required, the configuration menu can largely be left at the defaults, so the device is… Read more

more or less point and shoot.

Unfortunately these devices, and all such contact-less infrared thermometers, are very sensitive to the surface being measured. This is not the fault of the machine, it's just physics. After some initial readings that were not what I expected, I checked it by using a pan of boiling water and another thermometer. Knowing the barometric pressure I knew the theoretical boiling point of the water, and this agreed within a degree with the QM7221 and the second thermometer. However It was very noticeable that the readings from the QM7221 varied significantly depending on the surface it was aimed at. When given a suitable surface it was within 0.5C of the theoretical temperature, but on other surfaces it varied and wouldn't give a stable reading. I checked this by using a piece of steel in the barbecue, and a shiny polished area gives a completely different (MUCH lower) and often much less stable reading than a rusty or matt black painted area.

It must be said that the inability to deal with shiny surfaces is described in the manual, with the advice to paint shiny articles matt black. The manual also gives examples of the emissivity of different materials so that the machine can be adjusted to suit. Sadly, in the real world it is not always possible to paint things and the inability to measure what the manual describes as "shiny or polished metal surfaces (stainless steel, aluminium etc.)" is a significant failing as many of the things I am interested in (such as exhaust pipes) tend to be shiny metal.

I have rated the QM7221 as "OK". If you want to measure surfaces that aren't shiny metal it would probably deserve a better score than that, especially as the limitation is described in the manual and is simply down to basic physics. Unfortunately I have found that many of the things I want to measure do in fact turn out to be "shiny metal" and so the issue, whilst no fault of the machine, does limit its usefulness in the real world.

Inaccurate Rubbish – Checked 3 of these in the shop. 2 were within half a degree of each other and the third was reading 1.5 degrees cooler on the same target so I purchased one of the first 2 and thought I might have a chance of some accuracy. Drove the 4 km home and felt the front discs on my vehicle. Very hot to touch. Digitech thermometer read 41.8 C. Are you… Read more

kidding? Felt the exhaust pipe… Very hot. could only touch it for half a second and know the temp was at least 85 C. The Digitech read 40.6 C?

Drove back to the retailer for a refund. More Chinese made rubbish.