SERVICE (cont.)
Electronic Controls (cont.)
Temperature Control Flow Charts (cont.)
H10X THERMOSTAT
PROBLEM: Boils Excessively - Fills Cup
If the indicator was on or blinking, the temperature sensor is operating properly, proceed to #7.
If the indicator was off, check the sensor connection on the electronic control circuit board and/or replace the temperature sensor and the electronic control as- sembly.
NOTE - Each temperature sensor is calibrated to an electronic control assembly. Both components MUST
Drain cup
Retry
Heater Light On While
Boiling
?
No
Yes
Replace Steam Sensor
be replaced as a set.
7. Check the voltage across the tank heater terminals |
with a voltmeter. Connect the dispenser to the |
power source. The indication must be 200 to 240 |
volts ac for 200 to 240 volt models while the red |
Disconnect Blue Wire From
Control Board Pin 7
Retry
Still Boiling
?
No
Finished
Yes
Replace Control Assembly
indicator on the circuit board is on or blinking. |
8. Disconnect the dispenser from the power source. |
Still Boiling
?
No
Yes
Replace Triac Assembly
Check For Split
Tank Heater
If voltage was present as described, the temperature control of the system is operating properly.
Replace Control Assembly
Temperature Control Test Procedure
1.Disconnect the dispenser from the power source.
2.Check the voltage across terminals 3 & 4 of the electronic control circuit board with a voltmeter. Connect the dispenser to the power source. The indication must be 200 to 240 volts ac for 200 to 240 volt models.
3.Disconnect the dispenser from the power source.
If voltage was present as described, proceed to #4.
If voltage was not present as described, refer to the Wiring Diagram and check the dispenser wiring har- ness.
4.Connect the dispenser to the power source .
5.Observe the red indicator on the electronic control circuit board.
6.Disconnect the dispenser from the power source.
If voltage was not present as described, contact Bunn-
9.Replace the electronic control assembly and tem- perature sensor.
NOTE - Each electronic control assembly is calibrated to a temperature sensor. Both components MUST be replaced as a set.
10.Check the voltage across the tank heater terminals with a voltmeter. Connect the dispenser to the power source. The indication must be 200 to 240 volts ac for 200 to 240 volt models while the red indicator on the circuit board is on or blinking.
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