Bunn Axiom Series Technical Training Manual page 27

Tank Heaters
The tank heaters are located inside the tank and secured to the
tank bottom.
Test Procedures:
1. With a voltmeter, check voltage across the white wire (120V
Models) or red wire (120/208-240V Models) from the terminal
block and black wire from the control board. Connect brewer to
the power source. The indication must be 120 volts ac for two
wire 120 volt models or 208-240 volts ac for three wire 120/208-
240 volt models (during a heating cycle).
2. Disconnect the brewer from the power source.
• If voltage is present as described, proceed to #3.
• If voltage is not present as described, refer to the Wiring
Diagrams and check wiring harness. If harness checks
ok, replace control board.
3. Disconnect the wires from the tank heater terminals.
4. Check resistance value across tank heater terminals and compare to chart.
• If resistance is present as described, reconnect the wires, the tank heater is ok.
• If resistance is not present as described, replace the tank heater.
NOTE- If any resistance is read between sheath and either terminal, remove and inspect heater for cracks in the
sheath.
Blanket Warmer
The blanket warmer is wrapped around the tank assembly.
Test Procedures:
1. Disconnect the brewer from the power source.
2. With a voltmeter, check voltage across the two wires at the warmer ele-
ment with the "ON/OFF" switch in the "ON" position. Connect the brewer to
the power source. The indication must be 120 volts ac for two wire 120 volt
models and three wire 120/208 and 120/240 volt models, or 230 volts ac for
two wire 230 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 Wiring Diagrams and check
wiring harness.
4. Check the resistance across the two terminals on the blanket warmer. Refer
to chart below.
• If resistance is to specification, reconnect the two wires to the blanket
warmer.
• If resistance is not to specification, replace the blanket warmer.
2268W
Large Dia.
HEATER
1425W-120V
3500W-240V
1850W-240V
3500W-200V
3000W-240V
2268W-240V
TERMINAL TO SHEATH - INFINITE (OPEN)
WARMER
50W-120V
50W-220V
Bunn-O-Matic Corporation
1425W
Small Dia.
RESISTANCE
10.10
16.46
31.14
11.43
19.20
6.35
RESISTANCE
288.0
968.0
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