There is no calibration for the count per liter you just need to put in a value pour and see what you get then repeat until it is right. start with 7000 and go from there
To help quicken the calibration process, if you know the number of pulses used to fill a know volume, you can quickly calculate the pulses/gal your flow meter generates.
(EDIT: You can also see the pulse count in phpmyadmin under the 'pours' table and you would have no need to alter the Config.py)
First you would have to change the Config.py as
@RandR+ has recommended when trying to troubleshoot and change these two lines to True
config['flowmon.debug' ] = True#False
config['dispatch.debug' ] = True#False
In the Rpints.log you will see the actual pulse count generated on your pour.
When you pour, pour into a metered or graduated vessel. As an example, I pour in a 0.5L pint glass. What is important is that you know the volume of your pour.
Set your taps to 7000 pulses/gal as RandR+ recommends.
Pour your beer to a given volume
Converting. 0.5L is 16.91oz
My flow meters generate 830 pulses to generate 16.91oz (That was my average after 3 pours)
830pulses / 16.91 oz =
49.08 pulses/oz
(128oz in a Gallon) =
6282 pulses/gal
Set that tap at 6282 pulses/gal. In theory, Maintaining your variables such as pressure, line length, and meter orientation can keep that pulses per gallon pretty true.