Bunn U3A service manual Troubleshooting, Problem, Probable Cause

Models: U3A U3

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TROUBLESHOOTING

A troubleshooting guide is provided to suggest probable causes and remedies for the most likely problems encountered. If the problem remains after exhausting the troubleshooting steps, contact the Bunn-O-Matic Technical Service Department.

Inspection, testing, and repair of electrical equipment should be performed only by qualified service person- nel.

All electronic components have 120 volt ac and low voltage dc potential on their terminals. Shorting of terminals or the application of external voltages may result in board failure.

Intermittent operation of electronic circuit boards is unlikely. Board failure will normally be permanent. If an intermittent condition is encountered, the cause will likely be a switch contact or a loose connection at a terminal or crimp.

Solenoid removal requires interrupting the water supply to the valve. Damage may result if solenoids are energized for more than ten minutes without a supply of water.

The use of two wrenches is recommended whenever plumbing fittings are tightened or loosened. This will help to avoid twists and kinks in the tubing.

Make certain that all plumbing connections are sealed and electrical connections tight and isolated.

This brewer is heated at all times. Keep away from combustibles.

WARNING – • Exercise extreme caution when servicing electrical equipment.

Unplug the brewer when servicing, except when electrical tests are specified.

Follow recommended service procedures

Replace all protective shields or safety notices

PROBLEM

PROBABLE CAUSE

REMEDY

Brew cycle will not start

1.

No water

 

2.

No power or incorrect voltage to

 

the brewer

Water lines and valves to the brewer must be open.

(A1) Check the terminal block for

120 volts ac across the red and white terminals and the black and white terminal on three wire 102/208 volt or 120/240 volt models.

(A2) Check the terminal block for 208 volts ac, 230 volts ac or 240 volts ac on "A Series" brewers across the red and black terminals on two wire single phase 208 volt, 230 volt and 240 volt models.

(A3) Check the terminal block for 208 volts ac, 240 volts ac, 380 volts ac across the black and blue terminals, the blue and red and the black and red terminals on three wire three phase 208 volt, 240 volt and 380 volt models.

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Bunn U3A service manual Troubleshooting, Problem, Probable Cause