TESTO 400 - Rechargeable Battery LED Status; Mains Operation; Switching the Testo 400 on and off

8 Commissioning
16
8.1.2 Rechargeable battery LED status
LED status Description
Lit up green Instrument is supplied with power
(battery fully charged)
Flashing green (rapidly) Instrument is on and being supplied
with power (battery is charging)
Flashing green (slowly)
Ready for operation in battery mode
Flashing green/red
Instrument is off and being supplied
with power (battery is charging)
Flashing red
Internal error, please restart. If the
error has still not been rectified,
please carry out a factory reset (see
Section 10.3.7). If the problem
persists, contact Testo Customer
Service.
8.1.3 Mains operation
1
Connect the USB mains unit to the USB interface/mains unit socket of
the testo 400 (see Section 7.2).
2
Connect the mains plug of the mains unit to a mains socket.

The measuring instrument is powered via the mains unit. The battery
charges.
8.2 Switching the testo 400 on and off
Current
status
Action Function
Instrument off
Press and hold down the
button (> 3 sec)
Instrument is switched on