Water is spitting out of the chimney while the machine is brewing. This may mean that the machine only produces a little bit of espresso, or none at all. Solutions for each are below:
If water is spitting from the chimney and the machine isn’t producing coffee:
This is because the boiler o-ring is out of position; when this is the case, water escapes from the lower boiler and overfills the upper boiler, causing it to splash out of the chimney. This article explains how to resolve this, and how to prevent it happening again.
If water is spitting from the chimney and the machine is producing a full shot of espresso
This is another easy fix. If the machine is spitting water from the chimney and it’s producing a full shot of espresso, you just need to fill the boiler with a little less water; we’d recommend 110g instead of 120g.
Additional step, only applicable to older machines
If you have a very early machine with a serial number less than 323, this article has an additional step which can help resolve this. All machines with a serial number of 323 or greater have already had this treatment.