TESTO 540 - Product description; First steps; Basic settings (configuration mode)

Maintaining the product16
Maintaining the product
Changing batteries:
1 To open the battery compartment, push the battery cover
down.
2 Remove used batteries and insert new batteries
(2x 1.5 V type AAA). Observe the polarity!
3 To close the battery compartment, push the battery cover
back on.
Cleaning the housing:
Clean the housing with a moist cloth (soap suds) if it is dirty.
Do not use aggressive cleaning agents or solvents!