G3

Overview

The BUNN G3 is a commercial bulk coffee grinder for grinding whole beans at the point of service. Its single hopper holds up to 3 lb (1.36 kg) of regular, decaf or specialty coffee beans. A grind selector provides a range of grind choices, making the unit suitable for coffee service that uses different brew methods, including drip, pour over, French press or espresso.

The grinder uses a bag sensor to prevent operation unless a bag is positioned behind the dispense chute or the brew cup is in place. Its Off/On/Start switch controls the grind cycle, and a cleaning lever helps clear coffee residue from the grind chamber after grinding.

Key Features

• 3 lb single hopper: Holds regular, decaf or specialty coffee beans.
• Adjustable grind selection: The selector allows the operator to choose among a wide range of grinds. The operating guide states that each setting provides the same grind each time it is selected.
• Bag and brew-cup sensor: Prevents grinding unless the bag is behind the dispense chute or the brew cup is in place. The manual cautions operators not to bypass this safety device.
• Cleaning lever: Helps clear coffee left from the previous grind from the grind chamber.
• Grinding burr warranty: BUNN lists a four-year warranty on grinding burrs. The service-manual warranty text specifies four years or 40,000 lb of coffee, whichever comes first.

Specifications

• Product: BUNN G3 commercial bulk coffee grinder
• Hopper count: One
• Hopper capacity: 3 lb (1.36 kg)
• Bean types: Regular, decaf or specialty coffee
• Dimensions: 27.2 in. high x 7.4 in. wide x 16.64 in. deep
• Weight: 56.24 lb
• Voltage: 120 V
• Phase: 1
• Amperage: 11 A
• Wattage: 1,320 W
• Plug: NEMA 5-15P
• Controls: Grind selector and Off/On/Start switch
• Safety feature: Bag/brew-cup sensor

Installation & Requirements

The G3 operating guide says to keep the grinder disconnected from its power source until the manual's Initial Set-Up instructions call for connection. Electrical service must be provided by an electrician and must meet applicable local and national codes. The listed electrical details for this G3 are 120 V, single phase, 11 A and 1,320 W, with a NEMA 5-15P plug.

The guide's CE requirements state that the appliance must be installed where trained personnel can oversee it, at an ambient temperature between 5°C and 35°C, and tilted no more than 10° for safe operation. It also states that the appliance must not be cleaned with a water jet or immersed for cleaning. These requirements do not replace the manual's model-specific setup instructions or applicable electrical codes.

Operation

Selecting a grind and grinding coffee

• Turn the selector knob until its arrow aligns with the desired grind setting. The guide notes that a selected setting provides a consistent grind each time it is used.
• Open the top lid, add whole-bean coffee and close the lid.
• Position the back of a bag behind the dispense chute or insert the brew cup so the sensor is activated. The grinder will not operate unless the sensor is activated.
• Press the Start switch to begin grinding. The Off/On/Start switch has three positions: Off/Stop stops the grinder; On is the resting position to which the switch returns after a grind cycle begins and remains after grinding stops; Start is momentary and initiates grinding when the sensor condition is met.
• Allow the bag to rest on the screen beneath the chute while grinding, as directed in the operating guide.

The sensor is a safety device. Do not try to bypass it. Use the grind selector to choose a setting for the coffee being prepared rather than changing or adjusting internal burr components as part of routine operation.

Cleaning & Maintenance

Cleaning the grinder

Disconnect the grinder from power before removing any panel or grind-chamber housing parts. To clear beans and loose grounds before disassembly, empty the hopper, reconnect the grinder, place an empty bag behind the dispense chute or the brew cup in position, and run a few cycles until coffee remaining in the grind chamber has been dispensed. Then disconnect power and remove the bag or cup. Unplug the grinder again before cleaning the grind chamber.

1. Wipe exterior surfaces with a damp cloth and mild, non-abrasive liquid detergent. Avoid abrasive materials that could scratch the grinder.
2. Remove the two screws holding the dial plate and take off the dial plate and selector-knob assembly.
3. Slide the burr auger rotor and spring assembly off the motor shaft and disassemble it for cleaning.
4. Remove the two screws securing the stationary burr to the grind chamber.
5. Remove the four screws at the top of the chute and take off the chute. Use pliers to remove the C-clips securing the flapper arm, then carefully remove the flapper pins. Note where each flapper spring is located.
6. Wash removed parts in a mild detergent solution with hot water, using a stiff, non-metallic bristle brush. Rinse thoroughly and let the parts air-dry before reinstalling them.
7. Clean the grind chamber, dial plate assembly, chute opening and dial plate opening with a dry, stiff, non-metallic bristle brush. Wipe with a clean cloth soaked in mild detergent and hot water.
8. Reinstall the spring and rotor with burr on the motor shaft. Align the motor-shaft slot with the rotor, reinstall the shear plate, then reinstall the rotor cup and grind-selector dial plate on the burr housing.

Do not clean the machine with a water jet or immerse it. The operating guide directs that preventive maintenance be performed at regular intervals by a qualified service technician. It lists weekly cleaning plus replacement of the dechaffer assembly at six months. At one year, it calls for checking and cleaning slide plates on grinders equipped with them, inspecting and cleaning or replacing burrs and the grind chamber if necessary, and adjusting burrs and grind time to the required particle size and throw weight. The guide warns that replacement parts or service resulting from failure to perform required maintenance are not covered by warranty.

Troubleshooting

If the grinder does not start, first check the operating condition described in the manual: the bag must be behind the dispense chute or the brew cup must be in place to activate the sensor. The Start position is momentary, and the grinder is not intended to operate when the sensor is inactive. Do not bypass the sensor. If cleaning or inspection requires removing panels or grind-chamber parts, disconnect the grinder from power first. The manual says a damaged power cord must be replaced by the manufacturer or authorized service personnel with the special cord available for that purpose. For technical service, the manual lists BUNN at 1-800-286-6070.

Applications

The G3 suits commercial coffee stations that need to grind beans for different coffee preparations. The manual supports choosing a grind setting for each coffee, while the product listing identifies regular, decaf and specialty beans for the hopper. Operators can select an appropriate grind for service such as drip coffee, pour over, French press or espresso, then grind into a bag or brew cup as supported by the sensor and dispense arrangement.