Bunn Hot Water Dispencer HW 2

Disconnect the dispenser from the power source

Disconnect the thermistor from J5 on control board

Loosen the set screw and the two screws securing the two half blocks together. Remove thermistor assembly from overflow tube

Install new thermistor on tube and slide down until it contacts the flared end. NOTE: It's critical that the thermistor be centered directly under the tube opening

Snug the set screw so the block assembly does not move around easily

Connect the thermistor to J5 on control board

NOTE: DO NOT TEST OPERATION WITH PANELS REMOVED, AS AIR MOVEMENT CAN HINDER PROPER READINGS ON THERMISTOR

Sign off on the steam sensor replacement

Warning: Disconnect the dispenser from the power source before starting the test

Voltage across terminals 3 & 4 of the electronic control circuit board within the correct range

Voltage across the tank heater terminals within the correct range

Was voltage present as described in the first test?

If voltage was not present as described, contact Bunn-O-Matic to order an electronic control board and temperature sensor for evaluation and proceed to next step

Replace the electronic control board

Voltage across the tank heater terminals within the correct range after replacing the electronic control board

Was voltage present as described in the second test?

If voltage was present as described, the temperature control of the system is operating properly. Return the new electronic control board or temperature sensor to Bunn-O-Matic for credit

Warning: Disconnect the switch harness from CBA before starting the test

Continuity present when switch is pushed in?

Connect ohmmeter red lead to the red wire (+) and black lead to tan wire (-)

Select the resistance/continuity or diode scale

Does the LED glow from the meter's battery power source?

Sign off on the dispense switch test

Remove all wires from the electronic control board terminals

Remove the six 6-32 screws holding the electronic control board to the component bracket

Disconnect the temperature sensor, overflow tube temperature sensor, and indicator wires from the electronic control board

Attach the temperature sensor, overflow tube temperature sensor, and indicator wires to the electronic control assembly

Fasten the new electronic control board to its bracket

Upload a photo of the reconnected wires

Refer to Fig 2 when reconnecting the wires

Review the initial set-up procedures on page 6

Sign off on the electronic control replacement

Warning: Ensure the dispenser is unplugged before starting the procedure

Both wires removed from the thermostat terminals

Top lid removed from the dispenser

Two #6-32 screws removed from the thermostat

New thermostat fastened to the mounting bracket

NOTE: Make sure that the capillary tube is away from any electrical termination and is not kinked

Grommet slid to the red mark on the capillary tube

Bulb inserted through the hole in the tank and grommet pressed firmly