Operation Manual

3
4 A large, powerful motor..
5 ..spins the rotary pump which pushes water into and through the machine. A factory-set, adjustable bypass
valve built into the pump regulates the pressure which the pump delivers for optimal performance. The
pump is activated whenever the user is extracting espresso, and it can activate automatically whenever the
machine needs to refill the steam boiler.
6 Just after the pump is a pressure relief valve. This valve serves two purposes. Except when the brew lever is
lifted to open the group, the brew boiler and its related plumbing are a sealed system. When water is heated
in a sealed container it expands with great force and the pressure which is created must be released. The
valve operates as an expansion valve during those times, venting the extra pressure into the drip tray.
The valve also acts as a safety valve. Although the pump regulates brew pressure on its own, this relief
valve is located as a safety device in case there is a problem with the pump. If the pressure becomes exces-
sive the valve opens and vents the excess water into the drip tray. It’s factory setting is around 14 BAR, well
above the normal pressure used to make espresso.
7 Depending on the current circumstances, a solenoid-operated valve decides whether water can be sent to
the steam boiler or not. Water enters the brew boiler through the preheating tube, through the steam boiler,
and fills the brew boiler by displacement. The brew boiler is always 100% full.
8 The steam/hot water boiler (which will be referred to from this point forward as the “steam boiler”) holds
steam as well as hot water. It is the pressure of the steam in this closed chamber and not the action of the
pump that dispenses hot water from low in the boiler. If the pump runs while dispensing hot water it is only
refilling the boiler and not actually pumping hot water.
9 Steam is dispensed off the top of the boiler. The pressure of the steam pushes the steam out of the boiler. If
the pump runs while you are releasing steam it is only refilling the boiler and not pumping steam.
10 Hot water for brewing espresso is held in a separate, smaller boiler which is used exclusively for brewing
espresso. Only the water from this boiler passes through the E-61 brewgroup. We will refer to this boiler as
the “brew boiler” from this point forward.
11 Steam is sent to the steam valve through a copper pipe.
12 Hot water is sent through a separate copper pipe to the hot water valve.
13 Two large-diameter pipes carry water to the brewgroup. These supply water to the group for brewing, but
they have another function. While the machine is idling (on, but not being used), water flows through these
pipes by convection currents to keep the group hot and ready to brew. The hottest water rises to the top of
the brew boiler and into the group. As it heats the group and loses some of its thermal energy, it becomes
slightly more dense (heavier) and flows out of the bottom of the group and back to the bottom of the brew
boiler and the cycle continues like this until you start a brew cycle at which time both pipes supply hot water
to the group.