The meter is delivered complete, with a 9V battery. Open the battery compartment cover on the back. Uncertain the battery respecting the good polarity.
Always remove the electrode protection before use.
PH measurement: In the event that the electrode was left dry, immerse it (up to 2.5cm) for a few minutes in pH 7.01 liquid to reactivate it - Choose PH mode -

You can measure
EC / TDS measurement: Immerse the probe - Choose mS / cm mode. Leave the probe submerged for a few seconds before taking a measurement, so that the temperature sensor has time to balance information.
After use: You should clean the probe and replace the wet sponge with storage liquid.

PH calibration: At one point (PH 7.01)
Immerse the electrode in an envelope of pH7.01 calibration liquid - Turn on in PH mode and wait for the data to stabilize.
With the black PH7 calibration button, adjust the data to 7.0
EC Calibration: At One Point (EC1413)
Immerse the electrode in an EC1413 calibration liquid envelope - Turn on in mS / cm mode and wait for the data to stabilize.
Using the black EC / TDS calibration button, set the data to 1.41

The calibration of both must be repeated at least every month.
Battery replacement of the combo PH and EC meter MW802
As soon as the battery is empty, the meter will turn itself off.
The battery change can only be done in a safe place (not dangerous) and placing a 9V Alkaline battery.
Turn off the meter, insert the battery in its compartment. Make sure the poles are still in contact with the battery and replace the cover.