Cleaning The Instrument; Questions And Answers; Measuring Method - TESTO 835 Mode D'emploi

10.2 Cleaning the instrument

Only use weak, commercially available neutral/ household cleaning agents (e.g. washing-
up liquid) to clean the instrument. Do not use aggressive cleaning agents or solvent!
Wipe down the housing with a damp cloth (with detergent).
Clean the IR lens carefully with a cotton bud dipped in water or medical alcohol.

11. Questions and answers

Question
lights up.
lights up.
Instrument cannot be
switched on.
Instrument switches itself off.
If we have not been able to answer your question, please contact your local dealer or
Testo Customer Service. For contact details, please visit www.testo.com/service-
contact.
12. Information on IR measurement

12.1 Measuring method

IR measurement is a visual measurement
Keep lenses clean.
Do not carry out measurement with foggy lenses.
Keep the measuring range (the range between the instrument and the measurement
object) free of obstacles. There must be no particles of dust or dirt, no humidity (rain,
steam) and no gases.
IR measurement is a surface measurement
If there is dirt, dust, frost, etc. on the surface, only the outermost layer is measured, i.e.
the dirt.
For vacuum-packed food, do not measure at air pockets.
Where the values are critical, always measure separately with a contact thermometer.
Particularly in the food sector: measure core temperature with a
penetration/immersion thermometer.
Adjustment time
If the ambient temperature changes (change of location, e.g. measurement
indoors/outdoors), the instrument must be allowed to equalise for 15 minutes for
infrared measurement.
12.2 Emissivity
Materials have various emission levels, i.e. they emit various amounts of electromagnetic
radiation. The emissivity of the instrument has a default setting of 0.95. This is ideal for
the measurement of non-metals (paper, ceramic, gypsum, wood, paints and varnishes),
plastics and foodstuffs.
Possible causes
Batteries dead.
Measuring values outside
the measuring range.
Low battery.
Instrument switches off
automatically 2 minutes after
a key was last actuated.
11. Questions and answers
Possible solution
Change batteries.
Keep to the permitted
measuring range.
Change batteries.
Switch the instrument on
again.
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