Brew pressure
A fixed valve, and no gauge
This machine has no pressure gauge and no pressure adjustment. The pump is rated 15 bar. A fixed black plastic valve on the pump's outlet limits the pressure at the coffee and sends the surplus back to the tank through the second tube.
Gaggia gives owners no way to check or change it, and the sources do not agree on what the factory figure is. They are listed below so you can see the spread.
What owners do: a different spring
Gaggia's manual does not cover this, and its safety booklet says repairs are only for a service centre authorised by Gaggia. The booklet also forbids modifications, and the retailer Whole Latte Love says none is required or recommended and that modifying the machine voids the warranty. What follows is what owners do, as two owner blogs and the UK retailer Shades of Coffee describe it for the 2019 machine onwards.
- Unplug, let the machine go cold and take the top cover off.
- Pull the valve's return tube up out of the tank.
- Put a rag under the valve.
- Undo the brass nut at the valve's outlet anticlockwise, check the rubber valve seat stays in place, and swap the spring.
- Reassemble and load the circuit.
Shades of Coffee sells 9, 6.5 and 5 bar springs and says they read 1 bar higher against a blind filter, so 9 shows 10. It reports that the 6.5 bar spring can let steam pressure leak past the valve unless seated carefully, and that the 5 bar spring makes steaming harder. If only one tube shows in your tank, it says its kit with an extra pipe is needed.