My Analox O2 EII sensor is showing the following code L20.6 . Can you tell me what this means?



The symbol for a low battery warning is shown by 'L' on the display. 

When present, please change the battery before using the instrument. Please replace the battery with a 9V Alkaline (PP3) battery

Battery Replacement

a) Loosen the 4 screws located on the front cover. The gasket seal is designed to prevent water leaking into the O2 EII® as a result the seal may be tight. Loosen the seal by moving the lid from side to side, and then carefully lift the cover.

b) Slide the battery out of its holder and disconnect the lead.

c) Connect the lead to the new battery and slide the battery into its holder, under the battery clip

d) Replace the cover carefully taking care that the sensor locates properly and that you do not trap any wires. Screw down until you feel the gasket tighten; do not over tighten the screws