Bunn Axiom Series - Page 26

AXIOM
®
Training Manual
26
Temperature Probe
The temperature probe is inserted through the tank lid assembly.
Test Procedures:
1. Connect the brewer to the power source.
2. With a DC voltmeter, check voltage across the two wires at J9 on control
board (Blackprobe to black wire, red probe to white wire. The indication should
be aproximately between 4vdc cool to 1vdc at ready temperature.
3. Disconnect the brewer from the power source.
• If voltage is present as described, circuit is working correctly, check high
limit thermostat (and TCO on 230V models).
• If voltage is not present as described, proceed to #4.
4. Disconnect temperature probe from J9 on control board. Check the
resistance across the two terminals of the temperature probe. The indication should be approximately between 10.5K
cool to 870 at ready temperature.
• Ifresistanceistospecication,replacethecontrolboard.
• Ifresistanceisnottospecication,replacethetemperatureprobe.
High Limit Thermostat
The limit thermostat is located inside the top cover on the front side of the
tank.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the wires from the limit thermostat.
3. With an ohmmeter, 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.
RellValve
Therellvalveislocatedinsidethefrontofthebrewer.
Test Procedures:
1.Enterprogramminglevel2,scrollto“ServiceTools”thenscrollto“RellValve”.
2.Brieyactivatetherellvalveinthetestmode.Withavoltmeter,checkthevoltageacrossthecoilwires.
3. The indication must be 120 volts ac for two wire 120 volt models and three wire 120/208 -240 volt models or 230
volts ac for two wire 230 volt models.
• If voltage is present, proceed to # 4.
• If voltage is not present, refer to Wiring Diagrams and check main
wiring harness. If harness checks ok, replace control board.
4.Checktherellvalveforcoilaction.Brieyactivatetherellvalveinthe
testmodeandlistencarefullyneartherellvalvefora“clicking”soundas
the magnetic coil pulls the plunger in.
• If the sound is heard as described and water will not pass through the
 rellvalve,theremaybeablockageinthewaterlinebeforetherell
valve or, the solenoid valve may require inspection for wear, and
removal of waterborne particles.
• If the sound is not heard as described, proceed to # 5.
5. Disconnect the brewer from the power source.
6.Checkforcontinuityacrosstherellvalvecoilterminals.
• Ifcontinuityisnotpresentasdescribed,replacetherellvalve.
• If continuity is present as described, there could be some debris in the valve.
Flow Control Body
Flow Control Washer
Strainer