Instructions

DO-400 Maintenance | 7
B-H86.0.21.DB214-1.0 19 / 29
NOTE
Read the following handling instructions before replacing batteries and follow them
step by step. If disregarded, the product could be damaged or the protection from
moisture could be diminished.
Description
Proceed as follows to replace the batteries.
Prerequisites
– The product is switched off.
Instruction
1. Unscrews the Phillips screws and remove the cover.
2. Carefully replace the two Mignon AA batteries. Ensure that the polarity is correct!
It must be possible to insert the batteries in the correct position without using
force.
3. The O-ring must be undamaged, clean and positioned at the intended depth. In or-
der to facilitate assembly and avoid damage, a suitable grease can be applied.
4. Fit the cover on evenly. The O-ring must remain at the intended depth!
5. Tighten the Phillips screws.
Outcome of an action
The product is now ready for use again.
7.3 Calibration and adjustment
7.3.1 Automatic calibration in the air
Description
The following steps describe how to calibrate the product automatically.
Prerequisite
– The product is switched on.
NOTE
Calibration takes place in air saturated with water vapour. The GCAL 3610 calibration
container or the storage bottle can be used for this purpose. The membrane of the
electrode must be dry for the calibration. Prior to performing the calibration of the
membrane, dab away water droplets from the membrane with a soft, dry cloth. The fol-
lowing must be observed when using the storage bottle:
Only insert the electrode far enough into the storage bottle that the membrane does
not come into contact with the water in the bottle.
Unscrew the lid of the storage bottle and only position it so that a small exchange of
air and pressure equalisation can take place
Instruction
1. Place the electrode in the calibration container. If necessary, wait until the temper-
ature has equalised and a stable value has been achieved.
2. Press the Function key for 4 seconds to open the Calibration menu. The display
shows (AL.
3. Release the Function key.
4. The product determines the correct value automatically.