Bunn Axiom Series - Page 27

Bunn-O-Matic Corporation
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specication,reconnectthetwowirestotheblanket 
warmer.
• Ifresistanceisnottospecication,replacetheblanketwarmer.
50W-120V 288.0
50W-220V 968.0
WARMER RESISTANCE
1425W-120V 10.10
3500W-240V 16.46
1850W-240V 31.14
3500W-200V 11.43
3000W-240V 19.20
2268W-240V 6.35
HEATER RESISTANCE
TERMINAL TO SHEATH - INFINITE (OPEN)
2268W
Large Dia.
1425W
Small Dia.