4 sourced reports, with what to check before you buy. Each one links to the page it was reported on.
Costly or dangerous
Three-way solenoid valve clogs with scale, stalling flow through the group head
The manufacturer's own service guide lists the three-way solenoid valve clogging as the leading cause of flow problems on the Classic Pro.
What to check. Expect the group head to lose flow over time as scale builds up; cleaning the solenoid valve requires opening the machine (roughly 30 minutes). Buyers should plan regular descaling (about every 90 days) or budget for a solenoid service.
A Home-Barista owner replaced the pump after noticing intermittent delays from hitting brew to achieving flow through the puck.
What to check. Pump failure shows up as slow or delayed flow; replacing it means opening the machine and risks breaking the plastic pump-mount tower. Budget for a pump service if flow delays appear.
Over-pressure valve ships set at about 12 bar instead of 9
A Home-Barista member reports the OPV is factory-set at 12 bar and that lowering it to 9-10 bar improved shots.
What to check. The factory OPV setting is higher than the usual 9-bar espresso standard, which can make shots run fast or bitter; adjusting the OPV is a known first tweak.
These reports come from the pages linked under each item: owner forums, repair guides and workshops. They are not a diagnosis of any one unit, and a careful check of the one you are buying still applies.
Text from the Kriko Espresso & coffee machines catalog, version 0.1.1, under the CC-BY-SA-4.0 license.
