Hello fellow Baristi

I work with a 4 months old la Marzocco Linea PB. Since we have been using a Rwandan single origin (red bourbon), a group head has been having problems with the flow meter. When pouring a shot the alarm flashes on the message display and led buttons, and the message that appears is FLOW METER NO PULSE. The shot has to be stopped manually. Technicians have came in but they don't seem to resolve the problem. The grind, espresso brewing ratio is the one recommended by the roaster, and the shot taste great. I think the Rwandan coffee has to many fines after being grounded, and those fines migrate and clog the filter baskets pores. The grinder is a 4 months old Mazzer. With the Guatemalan and Kenyan single origin used before, there weren't any issues with the flowmeter. Any thoughts? Thanks you

Sounds like the flow from the portafilter might be too slow at the beginning of the shot. The programming is made to check to be sure there is coffee flowing after the brew button is pressed. If the shot is very slow then the machine may thing there is no water being pushed through the coffee and trigger the flow alarm

BillC