User Manual

6 Using the product
38
6.2. Measuring
NOTICE
Damage to the infrared detector by measuring high scene
temperatures.
> testo 875i without high-temperature filter: do not direct the
thermal imager at areas > 500°C / 932°F.
> testo 875-2i with high-temperature filter: do not direct the
thermal imager at areas > 800°C / 1472°F.
testo 875-2i: When measuring temperatures > 350°C or
> 662°F, always install the high-temperature filter, see
Mounting/removing high-temperature filter (testo 875-2i
only), page 19, and adjust the high-temperature
measurement range, see Measuring range, page 28.
With the high-temperature measuring range (350.0 -
550.0 °C or 662.0 - 1022 °F) activated, the stated accuracy
specifications are not valid for readings below 350 °C or
662 °F as this range is not calibrated.
Important framework conditions
Please observe the following framework conditions in order to
obtain significant measurement results.
Humidity measurement (only testo 875-2i):
• Pivot radio humidity probe or separate humidity measuring
instrument slightly to shorten the adjustment time. (e.g.
breathed air).
Building thermography, investigating the building shell:
• Considerable temperature difference between inside and
outside required (ideal: > 15 °C/> 27 °F).
• Consistent weather conditions, no intensive sunlight, no
precipitation, no strong wind.
To ensure the highest level of accuracy, the imager requires an
equalization period of 5 minutes after being switched on.
Important settings
Before recording an image, check whether the protection glass
option is set correctly to prevent corruption of the measurement
results, see Optics..., page 34.