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® S,SA
BUNN
ST,STA
STF,STFA
DISCONTINUED VERSION
The information in this manual
is no longer current.
OPERATING & SERVICE MANUAL
BUNN-O-MATIC CORPORATION
POST OFFICE BOX 3227
SPRINGFIELD, ILLINOIS 62708-3227
PHONE: (217) 529-6601 FAX: (217) 529-6644
www.bunnomatic.com
29251.0000G 04/01 ©1998 Bunn-O-Matic Corporation
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WARRANTY Bunn-O-Matic Corp. (“Bunn”) warrants the equipment manufactured by it to be commercially free from defects in material and workmanship existing at the time of manufacture and appearing within one year from the date of installation. In addition: 1.) Bunn warrants electronic circuit and/or control boards to be commercially free from defects in material and workmanship for three years from the date of installation. 2.) Bunn warrants the compressor on refrigeration equipment to be commercia
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USER NOTICES (Continued) #00882.0000 #00656.0000 #02763.0000 #02765.0000 #02769.0000 29251 101598 Page 3
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ELECTRICAL REQUIREMENTS CAUTION - The brewer must be disconnected from the power source until specified in Initial Set-Up. Model 15 has an attached cordset and requires 2-wire grounded service rated 120 volts ac, 15 amp, single phase, 60 Hz. L2 RED WHITE WHITE 120V A.C. WHITE NEUTRAL 208 or NEUTRAL 100V.A.C. 120V.A.C. 240V.A.C. L1 BLACK L1 BLACK NEUTRAL 120V A.C. L1 BLACK P2185 P1841 P2185 P2193 Model 20 requires 2- Model 35 requires 3- “A" & "B” models re- "SDB” model requires wire, grounded se
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INITIAL SET-UP CAUTION - The brewer must be disconnected from the power source throughout the initial set-up, except when specified in the instructions. 1. Insert an empty funnel into the funnel rails. 2. Place an empty dispenser under the funnel. 3. Remove the front or rear panel and turn the thermostat knob to the “OFF” position and connect the brewer to the power source. 4. Fill the tank with water as directed: 4A. Models S & SA: Pour three pitchers of tap water into the screened area on top
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OPERATING CONTROLS Models S & SA: These models function without operating controls. Models ST, STF, STA & STFA: ON/OFF SWITCH Placing the "ON/OFF" switch in the "OFF" lower position stops brewing. Stopping a brew cycle after it has been started will not stop the flow of water into the funnel until the tank syphons down to its proper level. Placing the switch in the "ON" upper position supplies power to the brew station warmer and enables the brew circuit and on Models STF and STFA refills the
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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 personnel. • All electronic components have 120 volt ac and low voltage dc potential on their terminals. Shorting of terminals or the appl
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TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Brew cycle will not start (cont.) 3. ON/OFF switch Refer to Service - ON/OFF Switch (ST, STF, STA & STFA) for testing. See page 17 4. Start switch Refer to Service - Start Switch for testing procedures. See page 19 5. Timer Refer to Service - Timer for testing procedures. See page 22 or 24 6. Solenoid valve Refer to Service - Solenoid Valve for testing procedures. See page 18 7. Strainer/flow control (.222 (A) Direction of flow arrow mus
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TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Inconsistent beverage level in dis- 3. Syphon system The brewer must be level or slightly penser (cont.) lower in front to syphon properly. 4. Lime build-up Inspect the tank assembly for ex- CAUTION - Tank and tank compo- cessive lime deposits. Delime as nents should be delimed regularly required. depending on local water condi- tions. Excessive mineral build-up on stainless steel surfaces can ini- tiate corrosive reactions resulting in serio
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TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Dripping from sprayhead 1. Syphon system The brewer must be level or slightly lower in front to syphon properly. 2. Lime build-up Inspect the tank assembly for ex- CAUTION - Tank and tank compo- cessive lime deposits. Delime as nents should be delimed regularly required. depending on local water condi- tions. Excessive mineral build-up on stainless steel surfaces can ini- tiate corrosive reactions resulting in serious leaks. 3. Solenoid valve
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TROUBLESHOOTING (cont.) PROBABLE CAUSE PROBLEM REMEDY 3. Solenoid valve (ST, STF, STA & Beverage overflows dispenser Remove the Solenoid Valve and STFA) (cont.) clean any obstruction. Rebuild or replace the valve if necessary. See page 18 1. Filter type Weak beverage The BUNN® paper filter must be used for proper extraction. 2. Coffee grind A fine or drip grind must be used for proper extraction. 3. Sprayhead A six-hole stainless steel spray- head must be used for proper extraction. 4. Funnel lo
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TROUBLESHOOTING (cont.) PROBLEM PROBABLE CAUSE REMEDY Brewer is making unusal noises 3. Water supply (A) The brewer must be connected (ST, STF, STA & STFA)(cont.) to a cold water line. (B) Water pressure to the brewer must not exceed 90 psi (620 kPa). Install a regulator if necessary to lower the working pressure to ap- proximately 50 psi (345 kPa). 4. Tank heater Remove and clean lime off the tank heater. See page 20 Automatic refill will not operate 1. No water Check plumbing 2. Strainer/flow
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SERVICE This section provides procedures for testing and replacing various major components used in this brewer should service become necessary. Refer to Troubleshooting for assistance in determining the cause of any problem. WARNING - Inspection, testing, and repair of electrical equipment should be performed only by qualified service personnel. The brewer should be unplugged when servicing, except when electrical tests are re- quired and the test procedure specifically states to plug-in the
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OFF BUNN SERVICE (cont.) CONTROL THERMOSTAT Test Procedures: 1. Disconnect the brewer from the power source. 2. Locate the blue wire on the control thermostat. 3. Check the voltage across the blue wire on the control thermostat and the white insert on two pole 100 or 120 volt terminal block or three pole 120/240 volt terminal blocks and the red insert on two wire 200 volt or 240 volt terminal block with a voltmeter. Connect the brewer to the power source. The indication must be: a) 120 volts
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OFF BUNN SERVICE (cont.) NOTE - The capillary tube must be clear of any electri- CONTROL THERMOSTAT (cont.) cal termination and not kinked. Removal and Replacement: 7. Models S & SA: Using two #8-32 screws secure 1. Remove wires from control thermostat leads. the control thermostat inside the rear inspection 2. Remove the thermostat capillary bulb by firmly panel. pulling-up on the capillary at the tank lid. This will Models ST, STA, STF & STFA: Using one #8-32 disengage the grommet from the tan
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SERVICE (cont.) LIMIT THERMOSTAT Removal and Replacement: 1. Remove all wires from limit thermostat termi- nals. 2. Carefully slide the limit thermostat out from under the retaining clip and remove limit thermo- stat. 3. Carefully slide the new limit thermostat into the retaining clip. 4. Refer to FIG. 5 when reconnecting the wires. BLK to Tank BLK to BLU Lead from P1586 Heater Switch Control Thermostat FIG. 4 LIMIT THERMOSTAT Location: The limit thermostat is located on the rear of tank assembl
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SERVICE (cont.) 5. With the black wire removed, remove from the lower terminal the white/red wire for the lower ON/OFF SWITCH (Models ST, STA, STF & STFA) warmer switch, the brown/black wire for the top front warmer switch or the blue/black wire for the top rear switch. 6. Check for continuity across the center and lower terminal with the switch in the "ON" position. Continuity must not be present when the switch is in the "OFF" position. If continuity is present as described, reconnect the blac
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SERVICE (cont.) 6. Check the solenoid valve for coil action. Connect SOLENOID VALVE (Models ST, STA, STF & STFA) the brewer to the power source. With "ON/OFF" switch in the "ON" upper position press start switch and listen carefully in the vicinity of the solenoid valve for a" clicking" sound as the coil magnet attracts. 7. Disconnect the brewer from the power source. If the sound is heard as described and water will not pass through the solenoid valve, there may be a blockage in the water line
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SERVICE (cont.) START SWITCH (Models ST, STA, STF & STFA) Removal and Replacement: 1. Remove the WHI/YEL and WHI/ORA wires from the start switch. 2. Compress the clips inside the hood and gently push the switch through the opening. 3. Push new switch into the opening and spread the clips to hold the start switch in the hood. 4. Refer to FIG. 11 when reconnecting the wires. WHI/YEL to Brew Timer TL3 WHI/ORAto Brew Timer TL5 P1589 FIG. 10 START SWITCH Location: P1591 The START switch is located fa
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SERVICE (cont.) TANK HEATER c) 200 to 240 volts ac for two wire 200 or 240 volt models. d) 100 volts ac for two wire 100 volt models. 3. Disconnect the brewer from the power source. If voltage is present as described, proceed to #4 If voltage is not present as described, refer to the Wiring Diagrams and check wiring harness. 4. Disconnect the black wire and the white wire or red wire from the tank heater terminals. 5. Check for continuity across the tank heater termi- nals. If continuity is pres
