The unit is locked due to calibration / the use of heavy duty battery. If you find heavy duty batteries have some how crawled their way into your unit, take them out, put them in the naughty corner and replace them with alkaline batteries.
If you cant remember the last time you had your unit calibrated, this is probably the reason. If you or your mates have downed some whisky and blown straight away into the unit, this could also be the cause. This method of sampling saturates (drowns) the sensor in alcohol and renders it useless... We don't recommend this method of testing...ever.

The accuracy of Andatech breathalysers is +/- 0.01% BAC to +/- 0.005% BAC depending on model and sensor.  This means that on average the BAC (Blood Alcohol Content) reading will be within 0.01%BAC of your true BAC level.  Most of law enforcement official have an accuracy of +/- 0.005% BAC.

If your unit uses a semi conductor sensor the accuracy will be within +/-0.01% BAC (Not bad)
If your unit uses a fuel cell sensor the accuracy will be within +/-0.005% BAC (Awesome)

Alcohol is absorbed into your bloodstream primarily through the stomach and intestines.  The rate of absorption depends on many factors, including your weight, whether or not there is food in your stomach and your body’s metabolic rate.  Deep within your lungs there are tiny blood capillaries that interface with the air.  This is where the alcohol in your bloodstream is evaporated into your exhaled breath.  The alcohol breathalyser then determines the content of alcohol in your breath.

Any type of alcohol breathalyser depends on an alcohol gas sensor to measure the content of alcohol in your breath.  Most professional breathalysers use a fuel cell alcohol sensor, while most consumer breathalyser use a less expensive semiconductor sensor. The content of alcohol in your breath is assumed to be directly proportional to that in your blood.

Professional quality alcohol breathalisers contain a flow sensor that requires that you blow for a minimum amount of time at a minimum flow rate to assure that you expel enough air out of your lungs to get to the "deep-lung" air, where the most accurate alcohol breathalyser reading can be obtained.  The better quality consumer breathalysers also contain a flow sensor so that they can obtain a deep-lung sample.

Please visit http://www.alcosense.com.au/support/ for instruction on how to send your breathalyser back for recalibration.

For a typical user, around 10,000 uses which equates to around 5 years. Less for heavy drinkers. Please note that calibration service is still needed as set out in the specifications and user manuals to ensure ongoing accuracy

Depending on your car's configuration, it should take at least 20 minutes to install.

Er2 means the sensor is not warm enough or the breathalyser receive a cold breath sample. Please try to inhale and exhale the breath sample from lungs. 

The majority of the AlcoSense breathalyser range has passed and been certified to Australian Standard AS3547.  This means that the breathalysers have been tested for accuracy, reliability and has proven to perform better than other breathalysers that are in the market without it. Australian Standard breathalysers undergo extensive laboratory and field testing in order to get this certification. This also means the breathalyser is serviceable and well supported through a strict control process as a safety device.