La Marzocco GS3 Product User Manuals & Instructions PDF

Welcome to the world of espresso craftsmanship with the La Marzocco GS3 Espresso Machine. Designed and manufactured in Florence, Italy, by one of the most renowned names in espresso machine engineering, the GS3 represents the pinnacle of performance, precision, and style.

Product Resource Details

Espresso Machine Installation, GS/3

  1. Fill Water reservoir with Water. Remove the drain tray and slide the water reservoir until the water reservoir fill cover is accessible. Remove the cover and fill water reservoir with filtered water. Replace the fill cover and slide the water reservoir to the operating position and replace the drain tray. (See GS/3 Installation Guide for addition instructions)
  2. Connect Espresso Machine to Power Supply. Connect the espresso machine to a power supply that is rated in accordance with the serial plate on the espresso machine.
  3. Filling the Boilers with Water. Once the espresso machine has been unpackaged, placed on a hard surface, and the water reservoir full, it will be necessary to fill the boilers with water. Complete the following steps to properly fill the boiler tanks:
  4. Steam Boiler. Turn the main switch to position “1” or ON, the automatic steam boiler level system will be switched on, activating the auto-fill solenoid valve and the water pump. This will fill the steam boiler to a predetermined level and will shut off when full. NOTE: It may be necessary to re-fill the water reservoir during this process. Check to see if the “Water Tank Empty” error message is present on the display before continuing.
  5. Coffee Boiler. The water flows inside the coffee boiler directly when the water pump is activated. When the GS/3 is turned on the electronics will activate the water pump to fi ll both boilers. Since the infl ow of water will compress the air in the boiler it will be necessary to remove or “bleed” the air from the coffee boiler. All air must be removed in order to completely “saturate” the coffee boiler/group assembly. To remove the air from the boiler (“bleed the groups”) remove the group cover from the top of the group head. Then loosen the bleed screw (see picture) to allow air to escape until water f l ows from below the screw head. It may be necessary to activate the brew process by pressing button #5 (the continuous button) to force the air out of the group. Tighten the screw to stop the water from fl owing. Over tightening can cause damage to the sealing washer and the group cap. If this sealing washer is damaged replace washer with one included in accessory kit. Once all air is removed from the coffee boiler, reinstall the group cover. For more detailed instruction please refer the GS/3 Installation Guide. NOTE: It may be necessary to re-fi ll the water reservoir during this process. Check to see if the “Water Tank Empty” error message is present on the display before continuing.
  6. Verify filling of Boilers. The installation is now complete and the espresso machine should be heating to the operating temperatures.
  7. Waiting for the Espresso Machine to Heat to Operating Temperature. During this time, it may happen that the pointer of the coffee boiler pressure gauge reaches as high as 12 bar. This may happen anytime that the heating element is in the on condition. If the pressure exceeds 12 bar then it will be necessary to adjust the expansion valve in such a manner that the pressure never exceed 12 bar. In normal operating conditions, the coffee boiler pressure gauge can read anywhere from 0-12 bar. When brewing, the pressure should be set to approximately 9 bar. When the espresso machine is ready to operate all lights on the keypads will light.
    NOTE: As the steam boiler reaches operating temperature you may hear air and steam escaping from the boiler. This is a normal sound. As the water boils, air in the boiler is replaced by steam and exits through the vacuum breaker. As the boiler get closer to operating temperature the vacuum breaker closes and the steam is no longer able to escape. This process allows the air in the steam boiler to escape and to be replaced by water vapor.
  8. Adjusting the Expansion Valve. The expansion valve is a component that limits the maximum pressure in the coffee boiler. Heating the coffee boiler causes the water within to expand. Since the coffee boiler is completly saturated, the expanding water causes an increase in pressure within the boiler. Without a safety device the increase in pressure could cause a rupture in the boiler. The pressure in the coffee boiler should never exceed 12 bar. To increase pressure rotate the expansion valve clockwise. To decrease pressure rotate the expansion valve counter clockwise (See the following diagram).
  9. Adjusting Water Pump Pressure. The water pump is factory set at 9 bar pressure. If it becomes necessary to change the pressure please use the following procedure:
  • Remove the left side cover assembly.
  • Locate the water pump adjustment screw and loosen the lock nut.
  • Adjust the water pump pressure to the desired measurement.
  • Rotate Clockwise to increase pressure and counter clockwise to reduce pressure.


La Marzocco
From top of the line home espresso machines to a wide range of commercial options, La Marzocco delivers. The Italian espresso authority was founded in 1927 in Florence, and has been a premier manufacturer of high-end espresso machines since the very beginning. Classic designs and construction meet incredibile innovations in espresso brewing to build a catalog of beloved machines.

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