There are a multitude of problems that can arise in espresso machines. Espresso machines are diverse pieces of machinery from the most complex machines that operate with bluetooth functionality to simple machines that operate with 3 primary components. The secret to circumventing issues with any espresso machine is fully understanding the functions and how to properly maintain it.
Coffee Not Dispensing
This can occur for a myriad of reasons including such issues as a clogged shower screen, clogged filter basket, the grind being too fine, a clog within the water circuit, not enough pressure building in the group, the recommended heat capacity not being reached, or a solenoid being clogged to name a few.
Start by checking your filter basket and shower screen. You can remove the shower screen by either removing the screw that holds it in place or removing the gasket that keeps it seated. Hold the shower screen up to the light and check to see that the holes are clear of coffee build-up. If not, replace the shower screen with a properly fitting new one. While the shower screen is removed, you can check the flow by releasing water through the group with a receptacle beneath it.
You can check the filter basket the same way. Coffee oils and residue can fill the holes making it difficult for coffee to permeate through the medium. If the filter basket has clogged holes, replace the cup or clean the old one by soaking it in espresso machine cleaner like Cafiza. Run water through the empty portafilter to see that cleaning or replacing this component corrected the problem.
Check the grind size by adjusting the grinder to a coarser setting and see that the permeability rate is up to par along with the crema formation. Every grinder is different, so ensure that you understand your grinders capabilities; you may need to replace the burrs within your grinder to attain the optimal grind quality.
A clog within the water circuit is a far more intensive troubleshooting method that involves testing the motor, pump, all lines within the circuitry, and boiler system. This may be something that you want to have a professional determine, as this takes a higher level of understanding of the safety precautions that need to be taken to safely troubleshoot these issues.
Pressure within the group is extremely important for the best shot pulling capacity. The pressure in the group includes the piping that feeds the group. Something as simple as a hairline fracture may lead to a poor shot by the shear factor that the pressure will not hold well enough to push the water through the coffee grounds in the filter basket, nor the shower screen.
Heating within the system is a common issue originating by many components; the heating element may have gone bad, corrosion within the piping may be leading to a reduced heat capacity, and incorrect metal alloys can also be the reason for issues in coffee not being hot enough.
A clogged solenoid is one of the most common issues with coffee not extracting properly. Solenoids are valves that determine when coffee is allowed to be released from the line to the next stage in the water circuit. It is essentially an open and close valve that works much like a water faucet.