The possibility of any hitch of a coffee maker must be revealed as soon as possible. The system of automatic diagnostics installed in some models of coffee makers provides a great help. Such machines are fit with sensors, indicators and special devices, which serve for notification of owners. Our troubleshooting table with error codes for bunn coffee makers below will help you to understand these notifications.
The NHBX coffee maker made by Bunn-O-Matic Corporation offers 4 to 10 five-ounce cups per batch. The model uses Bunn filters that are produced with a special grade of paper and have taller sides. It is also equipped with a patented ready-to-brew reservoir and an exclusive sprayhead designed to create the right amount of turbulence.
| Problem | Suggestions |
|---|---|
| Coffee not coming out | • Initial set up required • Make sure lid is closed. • Evaporation can occur over time - reservoir may need to be refilled. • Requires a minimum of 4 cups (20 oz) to begin brewing. • Check sprayhead holes, clean if necessary. |
| Brewed only partial decanter | • Evaporation can occur over time - reservoir may need refilled. • Some water is always absorbed by the coffee grounds and filter. You may need to adjust water input accordingly. |
| Funnel is overflowing | • Use BUNN paper filters. • Sprayhead is missing. • Decaffeinated, fine grind coffee or softened water is used. |
| Coffee is cold | • Plug in brewer and turn on vacation switch on side of brewer. Allow 15 minutes for water to heat to proper temperature. |
| Coffee is not staying hot | • Warmer switch should be in the “on” position. (BX, GRX, NHBX) • If using a BTX with thermal carafe, pre-heating will increase the time your coffee will stay warm. |
| Loud rumbling noise | • Normal while water is heating. • May be time to delime. |
| Waterflow begins before lid is closed | • Make sure lid is fully open. • Brewer is not designed to hold water in upper tray for an extended period of time. • Remove top lid to ensure rocker arm is snapped in place and rubber stopper area is thoroughly cleaned. |
| Deliming tool doesn’t go in all the way |
AXIOM is a series of coffee makers produced by Illinois-based manufacturer of coffee- and tea-making equipment Bunn-o-Matic Corporation. The series includes over 15 coffee machines ranging in capacity (up to 3 liters) and key features.
| PROBLEM | PROBABLE CAUSE | REMEDY |
|---|---|---|
| Temperature Too Low | 1. Water temperature in the tank does not meet the ready temperature. | A) Wait for the brewer to heat to the proper temperature. B) Disable the BREW LOCKOUT function. procedure. |
| Heating Time Too Long | 1. Tank Heater failure. 2. Control Board/Thermistor failure | Service required |
| Fill Time Too Long | 1. Water shut off to brewer 2. Supply line too small or obstructed 3. Inlet Solenoid failure 4. Control Board Failure 5. ON/OFF switch is OFF | Check water supply shut-off Replace or repair as needed Service Required Service Required Turn switch ON |
| Temp Sensor Out Of Range, Check For Bad Connections | 1. Temperature Sensor Probe wire(s) broken or not making connection | Service required |
| Temp Sensor Out Of Range, Check Wire For Shorts | 1. Temperature Sensor Probe wire(s) shorted to housing or to each other. | Service required |
| Equipment will not operate | 1. No power | Verify power cord is plugged into outlet. |
| 2. Incorrect voltage | Service required | |
| Water fl ows into tank continuously with power removed from brewer | 1. Refi ll valve | Service required |
| Brew cycle will not start | 1. No water | Check plumbing and shut-off valves |
| 2. Water temperature in the tank does not meet the ready temperature. | A) Wait for the brewer to heat to the proper temperature B) Disable the BREW LOCKOUT function. | |
| 3. "ENABLE BREW ON/OFF" switch not on. | Turn on | |
| 4. Brew switch | Service required | |
| 5. Brew valve | Service required | |
| 6. Control Board | Service required | |
| Spitting or unusual steaming from sprayhead or air vent. | 1. Lime buildup | |
| 2. Temperature probe | Service required | |
| 3. Control Board | Service required | |
| Inconsistent beverage level | 1. Lime buildup | |
| 2. Brew valve | Service required | |
| Dripping from sprayhead. | 1. Brew valve | Service required |
| Water overfl ows fi lter. | 1. Type of paper fi lter | BUNN paper fi lters should be used for proper extraction |
| 2. No sprayhead | Replace sprayhead | |
| Beverage overfl ows decanter | 1. Beverage left in decanter from previous brew | The brew cycle should be started only with an empty decanter under the funnel. |
| 2. Brew volume adjustment | Adjust the brew volume, calibrate sprayhead as required to achieve the desired volume for each brew cycle. | |
| Weak beverage. | 1. Type of paper fi lter | BUNN paper fi lters should be used for proper extraction |
| 2. Coffee | For coffee, a suffi cient quantity of fresh drip or regular grind should be used for proper extraction. | |
| 3. Sprayhead | A BUNN sprayhead should be used to properly wet the bed of ground coffee in the funnel | |
| 4. Funnel Loading | The BUNN paper fi lter should be centered in the funnel and the bed of grounds leveled by gently shaking. | |
| 5. Water temperature | Place empty funnel on top of an empty server (not in the funnel rails). NOTE: Do not remove sprayhead! WARNING: HOT WATER Press brew. Check water temperature immediately below the sprayhead with a thermometer. Recommended reading should be at least 195°F (90°C). | |
| 6. Incorrect recipe | Consider adjusting brew volume, and/or BREW METER. | |
| Brewer is making unusual noises. | 1. Solenoids vibrating | Service required |
| 2. Plumbing lines | Plumbing lines should not be resting on the countertop. | |
| 3. Water supply | The brewer must be connected to a cold water line. Water pressure to the brewer must not be higher than 90 psi (620 kPa). Install a regulator if necessary to lower the working pressure to approximately 50 psi (345 kPa). | |
| 4. Tank heaters | Service required |
Bunn CDBC is a range including over 25 automatic thermal carafe coffee brewers. There’re coffee makers of small, large, and extra-large capacity (up to 12 cups, or 25.77 liters in CDBCF15-TC). The space-saving models are 9’’ wide and boast SplashGard funnel helping to deflect hot water from your hands.
| PROBLEM | PROBABLE CAUSE | REMEDY |
|---|---|---|
| Will not fill or refill | 1. Power off to brewer | Press OFF/ON switch on control panel to determine if power is ON |
| 2. Water shut off | Make sure water is ON. | |
| 3. Display flashing | Brewer has shut down due to malfunction | |
| 4. ON/OFF Switch | Make sure ON/OFF Switch is "ON" and indicator is lit. | |
| 5. Lime build up on Probe | Remove the Level Probe and check for lime deposit on tip. Clean and reinstall. | |
| 6. Refill Valve or Control Board | Disconnect the brewer from the power source and remove wires from refill valve coil. Check for continuity across the terminals of the solenoid coil. If continuity is not present, replace the refill valve. If continuity is present, the coil may be stuck closed. Shut water off to brewer. Set the ON/OFF switch to the "OFF" position. Open the faucet and drain water down in the tank until flow stops or slows to a trickle. Attach a voltmeter to the terminals of the refill solenoid. Connect the brewer to the power source. Press the switch "ON". Within five seconds, voltage should be present at the solenoid terminals. | |
| Fill or refill does not shut "OFF" (ON/ OFF Switch "ON") | 1. Lime build up on probe | Remove Level Probe and check for lime deposits on tip. Clean and reinstall. |
| 2. Water Level Probe Sensing System | Disconnect the brewer from the power source. Disconnect the J3 connector from the control board. Check for continuity from the nut on top of the level probe to pin 1 of the plug, continuity should be present. Pull the temperature probe up about an inch from the grommet. Check for continuity from the outside surface of the temperature probe and pin 4 of the plug, continuity should be present. Connect the J3 plug to the control board and proceed to step 3. | |
| 3. Refill valve or control board | Press ON/OFF switch to "ON" (Indicator lamp should be lit). If water continuously flows out of air vent tube, disconnect the brewer from the power source. If water flow stops, replace the control board. If water flow does not stop, repair or repla | |
| Fill or refill does not shut "OFF" (ON/ OFF Switch "OFF") | 1. Refill valve or control board | If water continuously flows out of air vent tube, disconnect the brewer from the power source. If water flow does not stop, repair or replace the refill solenoid. If the valve closes when power is removed, replace the control board. |
| Water does not heat to proper temperature | 1. Display flashing | Brewer has shut down due to malfunction |
| 2. Water not touching temperature probe | Remove temperature probe and grommet. Look into hole on tank lid. Water must be within one inch from top of tank. | |
| 3. Water Level Probe Sensing System | Disconnect the brewer from the power source. Disconnect the J3 connector from the control board. Check for continuity from the tank mounting screw where the green wire mounts, to pin 2 of the plug, continuity should be present. Pull the temperature probe up about an inch from the grommet. Check for continuity from the outside surface of the temperature probe and pin 4 of the plug, continuity should be present. Connect the J3 plug to the control board and proceed to step 4. | |
| 4. Temperature Probe | Remove the probe from the grommet and submerge in a water bath of approximately 70°F(21°C). Connect an ohmmeter to pins 3 and 4 of the J3 connector. At 60°F(16°C) the reading should be 15.3k ±2k OHMS, at 70°F(21°C) the reading should be 11.8k ± 2k OHMS, and at 80°F(27°C) the reading should be 9.3k ± 2k OHMS. If the probe is within these parameters, reconnect the J3 plug to the control board. | |
| 5. Limit Thermostat | Disconnect the brewer from the power source. Check for continuity across the limit thermostat terminals. Continuity should be present. If not replace the limit thermostat. | |
| 6. Tank Heater | Disconnect the brewer from the power source. Check for continuity between the white terminal of the terminal block (or red terminal on 208/240volt models) and the black wire on the relay on the control board (Toggle Switch must be in 120/208-240V position on 208V & 240V models). There should be a low OHM reading. If no continuity is present, check for a wiring problem, then replace the tank heater if no wiring problem is found. | |
| Spitting or excessive steaming (cont.) | 1. Lime build up on temperature probe, tank or tank heater | Inspect probe and tank assembly for excessive lime deposits. Delime as required. |
| 2. Temperature Probe | Remove the probe from the grommet and submerge in a water bath of approximately 70°F(21°C). Connect an ohmmeter to pins 3 and 4 of the J3 connector. At 60°F(16°C) the reading should be 15.3k ±2k OHMS, at 70°F(21°C) the reading should be 11.8k ± 2k OHMS, and at 80°F(27°C) the reading should be 9.3k ± 2k OHMS. If the probe is within these parameters, reconnect the J3 plug to the control board. | |
| 3. Control Board | Set the temperature to 200°F(93°C). Let tank temperature stabilize. If temperature in tank is above temperature setting by more than 7°F, replace the control board. | |
| Brewer is making unusual noises | 1. Plumbing lines | Plumbing lines should not rest on the counter top. |
| 2. Water supply | The brewer must be connected to a cold water supply. | |
| 3. Lime build up | Remove the tank lid and clean inside of tank with a deliming agent, if necessary. | |
| Brew cycle will not start | 1. Display flashing | Brewer has shut down due to malfunction |
| 2. No water | Water lines and valves to the brewer must be open. | |
| 3. No power or incorrect voltage to the brewer | Check for voltage across the terminals at the terminal block. | |
| 4. ON/OFF switch not in the "ON" position | The indicator lamp must be lit | |
| 5. Low water temperature (Brew lockout is enabled) | Allow brewer to heat until ready lamp is lit, or disable the brew lockout feature. | |
| 6. Water not touching refill probe inside tank | Press ON/OFF switch (indicator must be lit). Brewer will refill until water touches probe inside tank. Water must be in contact with refill probe before brew cycle will start. | |
| 7. Switch panel | Disconnect the brewer from the power source. Disconnect the ribbon connector from the control board. Check for continuity between pins 1 & 2 (An arrow on the connector indicates pin 1). No continuity should be present. Press the BREW switch. Continuity should be present for as long as the switch is held down. If no continuity is present, replace the switch membrane decal. | |
| 8. Control board or dispense valve | If the switch panel is operating properly, proceed as follows. Attach a voltmeter to the terminals of the dispense solenoid. Connect the brewer to the power source. Turn on the brewer and press the BREW switch. Voltage should be present at the solenoid terminals. If voltage is present, check for continuity across the terminals of the solenoid coil. If continuity is not present, replace the solenoid. If continuity is present, the valve may be stuck closed. | |
| Consistently low beverage level in the dispenser or beverage overflows dispenser | 1. Brew volume NOTE: Volume adjustments must be made with sprayhead installed. | Set up brewer according to instructions in section Adjustments-Brew Volumes. Using a stop watch or second hand, time the length of the brew cycle. Record this time inside the top lid. |
| 2. Lime build up | Inspect the dispense valve and sprayhead for excessive lime deposits. Delime as required. | |
| 3. Dispense Valve | Remove dispense valve and clear any obstructions. Rebuild or replace valve if necessary. | |
| Dripping from sprayhead | 1. Lime build up | Inspect the tank assembly for excessive lime deposits. Delime as required. |
| 2. Dispense valve | Remove the dispense valve and clear any obstructions. Rebuild or replace the valve if necessary. | |
| Weak beverage | 1. Sprayhead | A clean sprayhead must be used for proper extraction. |
| 2. Water temperature | Place an empty brew funnel on an empty decanter beneath the sprayhead. Initiate brew cycle and check the water temperature immediately below the sprayhead with a thermometer. The reading must not be less than 195°F (91°C). Adjust the temperature setting to increase the water temperature. | |
| 3. Filter type | BUNN® paper filters must be used for proper extraction. | |
| 4. Coffee grind | A fine drip or grind must be used for proper extraction. | |
| 5. Funnel loading | The BUNN® paper filter must be centered in the funnel and the bed of grounds leveled by shaking gently. |
The G9 HD coffee maker is manufactured by the Bunn-o-Matic Corporation based in Springfield, Illinois. It caters for a wide audience, from the novice through to the experienced barista. Depending on your personal preferences the grind may be set from very fine to very coarse.
| Problem | Probable Cause | Remedy |
|---|---|---|
| Grinder will not start. | 1. Motor overload protector | Remove the cover plate located on the right side of the housing. Press the red “Reset” button. Listen carefully for a “click”. This resets the motor protection circuit and indicates that an overload may have been encountered by the motor. (An overload can occur when something other than coffee is inserted into the hopper for grinding.) |
| 2. No power or incorrect voltage | Check the voltage at the power cord with a voltmeter. Voltage must be: (A) 120 volts across the black and white wires for 120 volt models. (B) 240 volts across the black and red/black wires for 240 volt models. is not present, refer to the wiring diagrams and check the wiring harness. | |
| 3. Off/On/Start switch | (A) Momentarily place the switch in the “START” (right) position. (B) Off/On/Start Switch for testing procedures. | |
| 4. Timer | ||
| 5. Relay | ||
| 6. Motor | ||
| Grinder will not shut off. | 1. Off/On/Start switch | (A) Place the switch in the “OFF” (left) position. (B) Off/On/Start Switch for testing procedures. |
| 2. Timer | ||
| 3. Relay | ||
| Grinder starts, but will not dispense. | 1. Hopper | Begin each grind cycle by visually inspecting the hopper for an ample supply of whole bean coffee. |
| 2. Bottom of hopper | Foreign materials must not block the opening at the bottom of the hopper. | |
| 3. Shear plate | ||
| Incorrect amount of coffee. | 1. Timer adjustment | |
| Incorrect coffee grind dispensed. | 1. Burr adjustment |
Bunnespress ES2C (ES-2C) is an espresso machine brewing fine espresso and related beverages. The coffee maker manufactured by the U.S. Bunn-o-Matic Corporation is equipped with two group heads, so you may select any to make one of four different programmed amounts of coffee. It is a discontinued model.
| PROBLEM | PROBABLE CAUSE | REMEDY |
|---|---|---|
| Equipment will not operate | No power or incorrect voltage | Connect the brewer to the power source. Check for proper voltage. Check circuit breaker/fuse. |
| Power switch | Must be in the “ON” position. Power indicator will glow. | |
| No water | Check plumbing and shut off valves. | |
| Brew cycle will not start | Water treatment or strainer | Direction of flow arrows must be pointing toward the brewer. Remove the strainer and/or water softener and check for obstructions. Clear or replace. |
| Will not brew when any of the batch buttons is pressed. (Continuous brew works as well as automatic refill.) | Flowmeter | Check connections between the flowmeter and electronic control unit. Replace flowmeter. |
| Solenoid valve | Check voltage at terminals. If voltage is present when the dose switch is pressed, disconnect power supply, remove wires from coil terminals and check coil terminal continuity. If there is continuity replace solenoid. | |
| Pump | When start switch is pressed, pump should turn on immediately. If this does not happen, check voltage at terminal block on the pump. If correct voltage is present, use a flat-blade screwdriver to turn the motor shaft on the rear end of the motor to see if the pump is locked. If the shaft does not turn, replace pump assembly. | |
| Water is not hot or long recovery time. | Solenoid valve | Remove the solenoid valve and clear it of any obstructions. Rebuild or replace the valve if necessary. |
| Limit thermostat(s) | Disconnect power supply , remove all wires check across limit terminals for continuity. If no continuity, replace limit thermostat(s). | |
| Tank heater | Check tank heater terminals for correct voltage. If voltage is present and machine is not heating properly, replace tank heater. | |
| Short brew time(less than approximately 20 seconds per half-cup). Weak coffee. No crema. | Coffee ground too coarse | Check coffee grind |
| Coffee not fresh | Use fresh coffee | |
| Too little coffee used | Adjust amount to taste | |
| Coffee not tamped into filter basket | Use tamper to press coffee into basket |
The Bunn ES2SA (ES-2SA) model belongs to the range of Bunnespress espresso/cappuccino coffee makers. The currently discontinued model boasts a unique espresso extraction chamber that gives you a chance to brew beverages of exceptional quality. In case of a coffee maker issue refer to the table below.
| Problem | Probable cause | Remedy |
|---|---|---|
| Equipment will not operate | No power or incorrect voltage | Connect the brewer to the power source. Check the contactor terminals for proper voltages. Check circuit breaker/fuse. |
| Contactor | When on/off toggle (master) is turned on , pilot lamp on base should light up and the contactor should energize and pull in. If contactor does not pull in, unplug brewer and check coil for continuity. If open, replace contactor. | |
| Toggle switch (Master on/off) | Must be in the on position. Pilot lamp will light. | |
| Brew cycle will not start | No water | Check plumbing and shut off valves. |
| Water strainer or filter | Direction of flow arrows must be pointing toward the brewer. Remove the strainer and/or filter cartridge and check for obstructions. Clear or replace. | |
| Start switch | Disconnect power supply and check terminals of switch for continuity (semi-automatic version) | |
| Solenoid valve | Check voltage at terminals. If voltage is present when the start switch is pressed, disconnect power supply and check coil terminal for continuity. If there is continuity, solenoid is defective. Replace solenoid. | |
| Pump | When starting switch is pressed, pump should turn on immediately. If this dies not happen, check voltage at terminal block on the pump.. If correct voltage is present, use a flat-blade screwdriver to turn the motor shaft on the rear end of the motor to see if the pump itself is locked up. If the shaft dies no turn, replace pump assembly. | |
| Start switch | Switch must make and break contacts. Check with ohmmeter for continuity. | |
| Water is not hot or long recovery time. | Limit thermostat | Check continuity of limit with ohmmeter. Disconnect power supply and check across limit terminals. If no continuity, replace limit thermostat. |
| Tank heaters | Check tank heater terminals for correct voltage. If voltage is present and machine is not heating properly, replace tank heater. A good tank heater will show continuity. |
PHASE BREW is a one-cup coffee maker boasting Heat and Release technology. The whole brew cycle is 10 minutes long. It includes the 6-minute heating phase and the 4-minute brewing phase. The Bunn-o-Matic Corporation appliance can be fixed with the help of the chart below.
| problem | suggestions |
|---|---|
| Brewer does not turn on | • Make sure brewer is plugged into a working outlet. • Press the On/Off Button to begin brew (red light will be illuminated). |
| Coffee is not brewing | • Make sure brewer is plugged into a working outlet. • Make sure brewer is filled with water. A minimum of 4 cups (20oz) is needed to begin brewing. • Make sure brewer clock is set. • Press the On/Off Button to begin brew (red light will be illuminated). • Check to see if Auto-Start time was programmed accurately. |
| Brew time is longer than usual | • Check Sprayhead holes for debris. Clean Sprayhead and perform Brewer Maintenance |
| Brew funnel overflows | • Be sure Brew Funnel is properly inserted. • Use BUNN paper filters – they are taller to prevent overflow. • Be sure Sprayhead is in place. • If overflow continues, contact BUNN for a Flow Restrictor Sprayhead. |
| Warmer plate stays on after brewing phase | • Warmer plate automatically shuts off after 2 hours. To shut off manually, push the On/Off Button (red light will turn off). |
| Programmed Auto-Start did not work | • Make sure AM/PM was accurately selected. • Reprogram for Daylight Savings Time or a power outage if needed. • Make sure Auto-Start button is illuminated. |
| Digital display flashes between time and ‘CLEA’ | • Perform Brewer Maintenance |
| Water drips through prior to completing Heating Phase or before programmed time | • Lime or mineral build-up may prevent the valve between the Top Tank and Sprayhead from properly closing. Perform Brewer Maintenance |
| Rumbling noise | • Normal while water is heating. • Will occur if you pour fresh water into unit immediately after brewing. • Will occur if you pour fresh water into unit when the warmer is still on from previous brew. |
| Off taste is detected | |
| Water heats but will not release | • If you are in a high altitude environment (over 4,000 feet), you will need a model with “D’ designation as the thermostat has been preset for high altitude environments. |
| Carafe is leaking from Pour Spout | • If you have a Carafe with a plastic Pour Spout, it is easy for coffee oils to build up on the shiny polished area. These coffee oils are difficult to see and can impact the pour. To clean the Pour Spout, use a small amount of mild detergent on the polished, shiny area. Use a soft cloth to scrub the shiny area of the Pour Spout until the film is gone. When finished, thoroughly rinse carafe and lid with clean water. |