TROUBLESHOOTING NO WATER AT THE GROUP
There are two main reasons there’s no flow coming from your group: a clog or a faulty brew valve. Have you been experiencing anything abnormal before the flow stopped? Low flow would likely indicate a clog, while strange noises would be more indicative of a faulty valve.
Have you checked the incoming water to the machine? Check the line coming out of the machine to the filter and to the wall. Make sure all of the valves are turned on.
Most espresso machines use solenoid valves to control the water flowing through the brew head. Engaging the group head causes these valves to open. Do you hear a distinct click when you push the brew button? If not your valve may be stuck closed or inoperable. You can check the solenoid tutorial to learn more about solenoids, and for some troubleshooting advice.
No water through the group head can also be caused by an obstruction, or clog, in the hydraulic system. Espresso machines have many water pipes that route water, and small metering jets called gigleurs to control the flow rate. Even with the best filtration systems, debris and buildup can block these tiny holes and cause water flow problems. Starting at one end of the system and checking for water flow can help you narrow down where the blockage may be.