La Marzocco Linea Classic User Manual

La Marzocco Espresso Machines Guideline
The La Marzocco espresso coffee machines work by forcing hot water under high pressure
through finely ground coffee held in a portafilter. The brewing process uses several key
components to accomplish this process.
Nearly every other espresso machine manufacturer uses a single boiler and heat exchanger
located inside the steam boiler. Water for brewing espresso is solely dependent on the
temperature of the single steam boiler and this creates inconsistent brewing and steaming
conditions, thus producing inconsistent drinks.
The La Marzocco espresso machine uses a unique two-boiler systems to isolate and perform
operations in the best possible conditions.
The rear boiler is dedicated to the steam and hot or tea water functions.
The front boiler has the sole purpose of providing brewing water at the correct temperature
and pressure for the coffee the barista is going to brew.
These temperature and pressure parameters are adjustable independently of any other
function of the espresso machine. They are also consistent though most any level of operation.
HOW DOES IT WORK?
Cold, filtered water enters the brewing boiler through a pump which raises the water pressure
to 9 bars to allow the water to flow through the finely ground coffee.
Then the water in the boiler is heated by a heating element, which is controlled by a
Temperature probe connected to a CPU which control and sends power to the element when
the water temperature is low and shuts off power to the element when the water is at
operating temperature.
This means the temperature of the coffee brewing water can be set precisely depending on the
operator's taste, the roast or blend of the coffee used.
When the barista puts the portafilter into the brewing group, it forms a watertight seal
between the portafilter and the group gasket.
When the user presses the brew switch, a solenoid valve opens and the pump generates
pressure to force the hot water from the boiler through the group and the diffusion screen and
screw, then into and through the ground coffee, producing the desired volume of espresso,
which is brewed into heated cups or shot glasses.
On automatic (AV) models, the water is measured by a flowmeter.

La Marzocco Linea Classic Specifications

General

Body Material	Stainless Steel
Steam Wand	Yes
Hot Water Dispenser	Yes
Boiler Material	Stainless Steel
Pump Type	Rotary
Power Requirements	Varies by model, please consult the official documentation
Power Consumption	Varies by model, please consult the official documentation
Water Tank Capacity	N/A (plumbed in)

Summary

Understanding Espresso Machine Operation

How Espresso Machines Work

Explains the fundamental process of forcing hot water through ground coffee using key components like boilers and pumps.

Key Espresso Machine Components

Boilers Explained

Details the function and operation of the two stainless steel boilers in La Marzocco machines.

Groups Explained

Describes the groups as brewing chambers and the importance of maintaining their temperature.

Group Valves

Explains the function of solenoid valves mounted under each group for water flow control.

Flowmeter Function

Details how the flowmeter measures water volume using an impeller and magnetic sensors.

Autofill System

Explains the system responsible for maintaining the correct water level in the steam boiler.

Vacuum Valve Operation

Describes the vacuum valve's role in preventing steam escape and ensuring accurate pressure readings.

Expansion Valve

Details the expansion valve's function in relieving front boiler pressure at approximately 12 bar.

Safety Relief Valve

Explains the safety relief valve's function to prevent the steam boiler from over-pressurizing.

Motor Pump

Describes the motor pump's role in increasing water pressure for brewing espresso.

Main Power Switch

Outlines the three positions of the main power switch: off, fill, and run.

Thermostat Operation

Explains how the thermostat controls the temperature of the front boiler using a bellows mechanism.

Heating Element

Details how heating elements in each boiler provide heat to the surrounding water.

Control Box Systems

Breaks down the control box into its constituent systems like power supply, autofill, and input.

Pressure Switch

Explains the micro pressure switch's role in controlling steam pressure and heating elements.

Espresso Machine Maintenance Procedures

Daily Group Head Cleaning

Step-by-step instructions for daily cleaning of espresso machine group heads and portafilters.

Daily Diffuser Screen Cleaning

Procedure for daily cleaning of diffuser screens and group heads using a cleaning solution.

Replacing Portafilter Gaskets

Detailed guide on how to remove old and install new portafilter gaskets correctly.

Relieving Group Airlock

Instructions on how to turn off power, remove panels, and loosen a bleeder screw to relieve an airlock.

Flowmeter Check (Authorized Tech)

Guidance for authorized technicians on checking the flowmeters of the espresso machine.

Group Valve Check (Authorized Tech)

Procedure for authorized technicians to inspect and check the espresso machine's group valves.

Inspect Brewing System for Leaks

Instructions on inspecting the brewing system for leaks, focusing on group valve and expansion valve.

Steam Valve Service (Authorized Tech)

Routine service recommendation for the steam valve, to be performed by an authorized technician.

Inspect Pump and Expansion Valve Pressures

Guide on inspecting and adjusting pump and expansion valve pressures for optimal performance.

Troubleshooting: Machine Doesn't Steam

Addresses issues when the espresso machine fails to produce steam, focusing on clogged steam tips.

Glossary of Espresso Machine Terms

Autofill System

Components for maintaining steam boiler water level: solenoid, probe, control box.

Ball Valve (Steam)

Valve to shut off steam flow to the steam valve assembly and wand for service.

Basket, Portafilter

Semi-permeable filter in the portafilter holding back coffee grounds.

Brain (Microprocessor)

Microprocessor controlling water volume on AV/espresso machines via menu pad.

Burrs, Grinding

Sharp plates that grind coffee to desired coarseness; flat or conical.

Button, Continuous Flow

Menu pad button for activating and deactivating continuous water flow.

Check Valve

One-way valve preventing hot water backflow into water supply lines.

Diffuser Screen

Spreads water flow evenly over espresso in portafilter insert.

Dose Weight

Weight of coffee dispensed into portafilter, typically 7 grams.

Element, Heating

Resistive coil inside boilers providing heat when electricity passes through.

Gasket, Element

Gasket sealing heating element to boiler end to prevent leaks.

Gasket, Portafilter

Gasket on group head underside for portafilter seal.

Grind

General description for the coarseness of ground coffee used for espresso.

Ground Connection

Provides ground reference for the autofill system.

Group Cap

Removable top cover on groups containing thermal limiter and bleed screw.

Group, Espresso Machine

Brewing head of the La Marzocco, filled with water for thermal stability.

Impeller, Flowmeter

Six-bladed wheel in flowmeter body with magnets for signaling the control box.

Impeller, Pump

Delicate graphite blades spinning rapidly to force water into the machine.

Keypad

Menu pad offering pre-programmed drink options and programming capabilities.

Portafilter

Handled device to hold ground, tamped coffee for brewing.

Pour Spout

Attachment at portafilter bottom directing espresso into cups.

Power Switch

Three-way switch applying power for dosing, filling, and heating elements.

Pressure Gauge, Double Scale

Measures steam and brewing pressure in bars.

Pressure, Tamping

Force applied to coffee in portafilter for desired shot time.

Scale

Dissolved mineral solid (calcium/lime) accumulating in machine, causing damage.

Sight Glass

Clear glass allowing operator to view water level in the steam boiler.

Solenoid Coil

Converts electrical energy into magnetic field to move valve plunger.

Solenoid Plunger

Rubber-sealed piston sealing valve seat to control water flow.

Tamper

Handheld device for applying pressure to ground coffee before brewing.

Thermostat

Device regulating temperature by controlling electricity to the brewing boiler element.

Tip, Steam Wand

Stainless steel nozzle used to direct steam into milk.

Valve, Expansion

Device that relieves excess pressure from the brewing system.