Bunn STA, STFA, SA service manual Troubleshooting

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 personnel.

•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 (ST, STF,	1. No water	Water lines and valves to the brewer
STA & STFA)		must be open.
	2. No power or incorrect voltage to	(A1) Check the terminal block for
	the brewer	120 volts across the black and
		white terminals on two wire 120
		volt brewers.
		(A2) Check the terminal block for
		120 volts across the red and white
		terminals and the black and white
		terminal on three wire 120/240
		volt brewers.
		(A3) Check the terminal block for
		200 volts on Model STFB brewers
		or 240 volts on "A Series" brewers
		across the red and black termi-
		nals.
		(A4) Check the terminal block for
		100 volts on Model SDB brewers
		across the white and black termi-
		nals.
		(B) Check circuit breakers or fuses.
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