BUNN ® OT & RT G IN RN WA ER RM WA DRY AT HE TER AY H AN AW HIG DEC ES IL IBL KS T BO UST RISUID NO MB LY DO P CO MP T LIQRD CO KEE ZA TO RE/HOHA E RE ILU FIR ILU FA FA S AND AS GL RNS BU ! OPERATING & SERVICE MANUAL BUNN-O-MATIC CORPORATION POST OFFICE BOX 3227 SPRINGFIELD, ILLINOIS 62708-3227 PHONE: (217) 529-6601 FAX: (217) 529-6644 10021.
CONTENTS Introduction ............................................................... 2 User Notices .............................................................. 3 Electrical Requirements ............................................. 4 Plumbing Requirements ............................................ 4 Initial Set-Up .............................................................. 5 Adjusting Brew Volumes ............................................ 6 Operating Controls.....................................
00656.0000 00688.
ELECTRICAL REQUIREMENTS CAUTION - Do not connect the brewer to the power source until specified in Initial Set-Up. L2 RED WHITE NEUTRAL L1 BLACK 120V.A.C. WHITE L2 RED 120V.A.C. 208 or 240V.A.C. NEUTRAL L1 BLACK RED 200 OR 240V.A.C. NEUTRAL L1 BLACK 100V.A.C. 120V.A.C. L1 BLACK MODELS OT15 & 20 require 2wire, grounded service rated 120 volts ac, 15 or 20 amp respectively, single phase, 60 Hz. Model 15 has an attached cordset.
PLUMBING REQUIREMENTS (Cont.) Plumbing Hook-Up Model OT15 has an attached water strainer, proceed to step 2. Models OT20, OT35, & RT35, proceed as follows: 1. Remove the rear panel and bottom pan. Run the long piece of tubing from the strainer (supplied) under the brewer and attach it to the water inlet fitting on the solenoid. Reinstall the bottom pan and rear panel. 2. Flush the water line and securely attach it to the 1/4" flare fitting on the strainer. 3. Turn on the water supply.
ADJUSTING BREW VOLUMES CAUTION - Disconnect the power source from the brewer prior to the removal of any panel for the replacement or adjustment of any component. NOTE: Prior to setting or modifying batch sizes, check that the brewer is connected to water supply, the tank is properly filled, and a funnel and server are in place. 1. Modifying batch sizes. To modify a batch volume, first check that the SET/LOCK switch is in the “SET” position on the circuit board. To increase a batch size.
MODELS OT & RT A. On/Off Brew Station Warmer Switch Placing the switch in the upper position supplies power to the brew station warmer and enables brewing. Placing the switch in the lower position cuts power to the brew station warmer and 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. E.
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 electric components have 120 volt ac voltage on their terminals.
TROUBLESHOOTING (cont.) Remedy Problem Probable Cause Brew cycle will not start. (cont.) 4. On/Off Brew Station Warmer Refer to Service - On/Off Brew Station Warmer Switch for testing proSwitch cedures. See page 19. 5. Start Switch Refer to Service - Start Switch for testing procedures. See page 25. 6. Brew Timer Refer to Service - Brew Timer for testing procedures. See page 13 or 14. 7. Solenoid Valve Refer to Service - Solenoid Valve for testing procedures. See page 24.
TROUBLESHOOTING (cont.) Problem Probable Cause Spitting or unusual steaming from 1. Control Thermostat sprayhead. 2. Lime build-up CAUTION: Tank and tank components should be delimed regularly depending on local water conditions. Excessive mineral build-up on stainless steel surfaces can initiate corrosive reactions resulting in serious leaks. Inconsistent beverage level in de- 1. Flow control canter. Remedy Refer to Service - Control Thermostat for testing procedures. See page 16.
TROUBLESHOOTING (cont.) Problem Probable Cause Remedy Beverage overflows decanter. 1. Beverage left in decanter The brew cycle should be started only with an empty decanter under the funnel. Weak beverage. 1. Type of paper filters BUNN® paper filters should be used for proper extraction. 2. Coffee A sufficient quantity of fine or drip grind coffee should be used for proper extraction. 3. Sprayhead B.O.M. sprayhead #01082.0000 should be used to properly wet the bed of ground coffee in the funnel.
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. Component Access WARNING - Disconnect the brewer from the power source before the removal of any panel or the replacement of any component. The brew timer, and control thermostat are located behind the front panel, FIG.
SERVICE (cont.) If voltage is present as described, reconnect the polarized, three-pin connectors, and proceed to #6. If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring harness. Brew Timer (Early Models) 7. 2 1 3 .5 4 5 MINUTES BUNN-O-MATIC P/N 2235-120 VAC 6. 8. P1690 FIG. 2 BREW TIMER Location: The brew timer is located behind the front panel to the right of the tank, FIG. 2. Test Procedure: 1.
SERVICE (cont.) DIGITAL BREW TIMER (Late Models) J1 6. Disconnect the white/blue wire from terminal TL3 and the blue/black wire from terminal TL5. With a voltmeter, check for continuity across the two wires when the "ON/OFF" switch is in the "ON" position (upper) and the START switch is pressed. Connect the brewer to the power source. The indication must be: a) 120 volts ac for two wire 120 volt models. b) 200 or 240 volts ac for two wire 200 or 240 volt models and three wire 120/240 volt models.
SERVICE (cont.) DIGITAL BREW TIMER (Late Models)(cont.) 3. Remove all wires from the timer. 4. Attach all wires to the replacement timer board prior to installation to the component mounting bracket. Refer to FIG. 5 when reconnecting the wires. 5. Install new circuit board with spacers (as required) to the component mounting bracket. 6. Adjust the timer as described below.
SERVICE (cont.) Control Thermostat 5. The indication must be as described in step 2. Voltage must not be indicated across these terminals when the thermostat is turned "OFF" (fully counterclockwise). Disconnect the brewer from the power source. If voltage is present as described, the control thermostat is operating properly. If voltage is not present as described, replace the control thermostat. U N N HI B Removal and Replacement: 1. Remove both wires from the control thermostat terminals. 2.
SERVICE (cont.) 5. Warmer(s) OT: Brew Station & Upper RT: Left Rear, Left Front, Brew Station, & Right Front Check for continuity from the wire terminal of the white or red wire to the splice or indicator lamp using the chart b5ew FIG. 8 WARMERS FIG. 9 WARMERS Location: OT: One of the warmers is beneath the brew funnel and the other is on the top lid, FIG. 8.
SERVICE (cont.) If continuity is present as described, proceed to #5. If continuity is not present as described, refer to the Wiring Diagrams and check the brewer wiring harness. Warmer RT: Right Rear Three Heat 5. Check for continuity across the two outside terminals on the warmer. Then across one of the outside terminals and the center terminal. Finally, across the other outside terminal, and the center terminal. If continuity is present as described, the warmer is operating properly.
If voltage is present as described, proceed to #4. If voltage is not present as described, refer to the Wiring Diagrams and check the brewer wiring harness. SERVICE (cont.) Warmer Switch(es) OT: On/Off Brew Station & Upper RT: On/Off Brew Station ! ION ANT UT D DEC CA DISCAR 4. 5. ER IF: D CKE . CRAATCHED TY . SCRED DRY N EMP ME WHE FLA IC . BOIL TED HIGH CTR .
SERVICE (cont.) 3. Warmer Switch(es) RT: Left Rear, Left Front, & Right Front 4. WAR NI If voltage is present as described, the switch is operating properly. If voltage is not present as described, replace the switch.
SERVICE (cont.) 5. Check the voltage across terminals L1 and 2 with a voltmeter when the switch is in the "High" position. Connect the brewer to the power source. The indication must be as described in step 1. Voltage must not be present across these terminals in the "Off", "Low", or "Med" positions. 6. Disconnect the brewer from the power source. 7. Check the voltage across terminals N and 1 with a voltmeter when the switch is in the "Med" or "High" positions. Connect the brewer to the power source.
c) 100 volts ac for two wire 100 volt models. SERVICE (cont.) 4. Indicator Lamp(s) Disconnect the brewer from the power source. If voltage is present, the indicator lamp is operating properly. If voltage is not present, replace the indicator lamp. ! ION ANT UT D DEC CA DISCAR Removal and Replacement: 1. Compress the clips inside the housing and gently push the indicator lamp through the opening. 2. Remove the wires from the indicator lamp terminals. 3. Refer to FIG. 22 when reconnecting the wires. 4.
SERVICE (cont.) 4. Limit Thermostat Check for continuity across the limit thermostat terminals. If continuity is present as described, the limit thermostat is operating properly. If continuity is not present as described, replace the limit thermostat. Removal and Replacement: 1. Remove both wires from the limit thermostat terminals. 2. Carefully slide the limit thermostat out from under the retaining clip. 3. Carefully slide the new limit thermostat into the retaining clip. 4. Refer to FIG.
4. SERVICE (cont.) Solenoid Valve 5. Check the solenoid valve for coil action. Connect the brewer to the power source, place the On/Off brew station warmer switch in the upper position, press and release the start switch. Listen carefully in the vicinity of the solenoid valve for a "clicking" sound as the coil magnet attracts and after the approximate setting on the brew timer dial, repels the plunger. Disconnect the brewer from the power source.
SERVICE (cont.) If continuity is present as described, reconnect the wires, the switch is operating properly. If continuity is not present as described, replace the switch. Start Switch ! ION ANT UT D DEC CA DISCAR Removal and Replacement: 1. Remove all wires from the switch terminals. 2. Compress the clips inside the housing and gently push the switch through the opening. 3. Push the new switch into the opening and spread the clips to hold the switch captive in the housing. 4. Refer to FIG.
SERVICE (cont.) Tank Heater FIG. 30 TANK HEATER Location: The tank heater is located on the tank lid, FIG. 30. Test Procedure: 1. Check the voltage across the black and white or red wires on the tank heater with a voltmeter when the control thermostat is turned "ON" (fully clockwise). Connect the brewer to the power source. The indication must be: a) 120 volts ac for two wire 120 volt models. b) 200 or 240 volts ac for two wire 200 volt or 240 volt models and three wire 120/240 volt models.
SERVICE (cont.) Thermal Cut-off Location: The thermal cut-off is located on the tank heater, FIG. 32. Test Procedures: 1. Disconnect the brewer from the power source. 2. Disconnect the thermal cut-off from the tank heater terminal and the wiring harness. 3. Check for continuity across the thermal cut-off terminals using an ohmmeter. If continuity is present, the thermal cut-off is operating properly. If continuity is not present as described, replace the thermal cut-off. Removal and Replacement: 1.
SCHEMATIC WIRING DIAGRAM OT L1 N GREEN BLK LIMIT THERMOSTAT L2 (FAUCET OPTION ONLY) THERMAL CUT-OFF SW. & THERMOSTAT BLU BLK BLK TANK HEATER WHI (OT15 & 20) RED (OT35) WHI WHI "KEEP WARM" HEATER BLK BLK P3 WHI BLK WHI P2 WHI UPPER WARMER BLK WHI BLK BLK WHI BREW STATION WARMER BLU BLK BLK P3 P1BLU/BLK WHI/BLU BLK P1, P2, & P3 ARE PINS OF A POLARIZED THREE-PIN CONNECTOR.
SCHEMATIC WIRING DIAGRAM OT L1 L2 GREEN SW. & THERMOSTAT LIMIT THERMOSTAT BLK N 3500W BLK BLU 50W WHI RED TANK HEATER WHI "KEEP WARM" HEATER BLK BLK P3 WHI 130W BLK P2 UPPER WARMER BLK BLK WHI WHI 130W BLK WHI WHI BREW STATION WARMER BLU BLK BLK P3 P1 BLU/BLK WHI/BLU BLK T1 T5 T3 BREW TIMER SELECTOR CONTROL BOARD 1/3 2/3 F PNK TAN BLK WHI/GRN T4 T2 GRY PNK TAN GRY GRN YEL RED SOL WHI P2 WHI P1, P2, & P3 ARE PINS OF A POLARIZED THREE-PIN CONNECTOR.
SCHEMATIC WIRING DIAGRAM OTA L1 L2 GRN/YEL BLK LIMIT THERMOSTAT SW. & THERMOSTAT BLU RED/BLK BLK TANK HEATER BLK BLK P3 BLK RED/BLK BLK RED/BLK P2 RED/BLK UPPER WARMER BLK RED/BLK RED/BLK BLK BLK BREW STATION WARMER BLK BLK 240 VOLTS AC 2 WIRE SINGLE PHASE 50-60 HZ BLU P1 BLU/BLK WHI/BLU P3 BLK SOL P1, P2, & P3 ARE PINS OF A POLARIZED WHI/GRN THREE-PIN CONNECTOR T1 T5 T3 T4 BREW TIMER T2 WHI P2 RED/BLK 10282.
SCHEMATIC WIRING DIAGRAM OT25B READY INDICATOR BLK BLU L1 SW. & THERMOSTAT LIMIT THERMOSTAT BLK BLK BLU BLK BLK K1 P3 BLK RED K1 RED RED TANK HEATER N.O K1 N.O RED BLK BLK N GRN/YEL BLK RED P2 RED UPPER WARMER RED BLK BLK BLK RED BREW STATION WARMER BLK BLK 100 VOLTS AC 2 WIRE SINGLE PHASE 50-60 HZ 10635.0000B BLU P1 BLU/BLK P3 WHI/BLU BLK SOL P1, P2, & P3 ARE PINS OF A POLARIZED WHI/GRN THREE-PIN CONNECTOR.
SCHEMATIC WIRING DIAGRAM OT35B READY INDICATOR BLU BLK L1 LIMIT THERMOSTAT BLK L2 GRN/YEL SW. & THERMOSTAT BLK BLU RED TANK HEATER BLK BLK P3 BLK RED RED BLK P2 RED UPPER WARMER BLK BLK RED BLK RED BREW STATION WARMER 200 VOLTS AC 2 WIRE SINGLE PHASE 50-60 HZ BLU P1 BLU/BLK BLK BLK P3 WHI/BLU BLK SOL WHI/GRN P1, P2, & P3 ARE PINS OF A POLARIZED THREE-PIN CONNECTOR. T1 T5 T3 10637.
SCHEMATIC WIRING DIAGRAM RT L1 N GREEN BLK (FAUCET OPTION ONLY) THERMAL CUT-OFF SW. & THERMOSTAT LIMIT THERMOSTAT L2 BLU BLK BLK RED TANK HEATER WHI WHI "KEEP WARM" HEATER BLK BLK WHI BLK WHI WARMER BLU BLK BLU/BLK WHI/BLU P3 BLK P1 BLK P1, P2, & P3 ARE PINS OF A POLARIZED THREE-PIN CONNECTOR. SOL WHI/GRN T1 T5 T3 T4 BREW TIMER T2 WHI P2 WHI OPTIONAL FLASHING INDICATOR SYSTEM GRY WHI/RED 4 INDICATOR 3 TIMER 2 1 L.E.D.
SCHEMATIC WIRING DIAGRAM RTA L1 L2 GRN/YEL SW. & THERMOSTAT LIMIT THERMOSTAT BLK BLU BLK RED TANK HEATER RED BLK RED BLK BLK WARMER BLU BLK BLU/BLK WHI/BLU P3 BLK P1 SOL BLK T1 T5 T3 P1, P2, & P3 ARE PINS OF A POLARIZED WHI/GRN THREE-PIN CONNECTOR.
SCHEMATIC WIRING DIAGRAM RT25B READY INDICATOR BLK BLU L1 LIMIT THERMOSTAT BLK N GRN/YEL SW. & THERMOSTAT BLU BLK BLK BLK K1 RED K1 RED TANK HEATER N.O RED K1 N.O BLK BLK RED BLK RED WARMER BLU BLK BLU/BLK WHI/BLU P3 BLK P1 BLK T1 T5 T3 SOL P1, P2, & P3 ARE PINS OF A POLARIZED WHI/GRN THREE-PIN CONNECTOR.
SCHEMATIC WIRING DIAGRAM RT35B READY INDICATOR BLK BLU L1 LIMIT THERMOSTAT BLK L2 GRN/YEL SW. & THERMOSTAT BLU BLK RED TANK HEATER BLK BLK RED BLK RED WARMER BLU BLK BLU/BLK WHI/BLU P3 BLK P1 BLK T1 T5 T3 SOL P1, P2, & P3 ARE PINS OF A POLARIZED WHI/GRN THREE-PIN CONNECTOR.
