a quick diagram to illustrate that a lot of the ‘extra bits’ that appear in the E61 diagram are not required with the lever, specifically a non-return valve on the feed out of the boiler into the thermosiphon is not required, and nor is an expansion valve as the water is coming in hot from the boiler & being cooled. simplicity = reliability
other things to note are the group does not mount directly to the boiler, unlike a dipper group (otherwise it would overheat)
the key message is that the pump does not run every shot. it only runs when the boiler hits the minimum level. it is a 2.3L boiler, so it is only like to run every 25 shots or so. in essence: you’ll hardly know it has a pump!
the words you can’t read (apologies) to the top left of the boiler are ‘solenoid inlet valve’
i hope the purists can see that we have kept it as simple as we can, whilst wanting to offer a lever machine that appeals to a much broader audience
to do that the focus is on a machine that is easy to obtain consistently exceptional shots from (assuming your grinder is up to the task)