Bunn FMD-4 - Manual (Page 21)

21
SERVICE (cont.)
16. Reconnect the ten pin connector of the wiring
harness to J2 of control board #1.
17. Gently pull the liquid level probe out of the tank lid
and inspect for corrosion. Replace it if necessary.
18. Place the probe so that neither end is in contact
with any metal surface of the dispenser.
19. Check the voltage across the terminals of the inlet
solenoid valve with a voltmeter. Connect the dis-
penser to the power source. The indication must
be 120 volts ac for two wire 120 volt models, three
wire 120/208 volt models, three wire 120/240 volt
models after a delay of approximately 10 seconds.
20. Move the probe’s flat end to the dispenser hous-
ing. The indication must be 0.
21. Move the probe’s flat end away from the housing.
The indication must, again, be 120 volts ac for two
wire 120 volt models, three wire 120/208 volt
models, three wire 120/240 volt models after a
delay of approximately 5 seconds.
22. Disconnect the dispenser from the power source.
If the voltage is present as described, re-install the
probe. The liquid level control circuitry is operating
properly.
If the voltage is not present as described, check the
pink probe wire and green tank wire for continuity.
CONTROL BOARD (CONT.)
Hopper Motor Control Circuitry (Stations 1-3, Control
Board #1 & Stations 4-5, Control Board #2):
1. Disconnect the dispenser from the power source.
2. Disconnect the six pin connector from J3 of the
appropriate control board.
3. Check the voltage across pins 5 & 6 of the six pin
connector on the wiring harness with a voltmeter.
Connect the dispenser to the power source. The
indication must be 24 volts ac.
4. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to step 5.
If voltage is not present as described, refer to the
wiring diagram and check the dispenser wiring har-
ness.
5. Reconnect the six pin connector of the wiring
harness to J3 of the control board.
6. Check that the rinse/run switch is in the run
position.
7. Check the voltage across the red (+) terminal and
the black (-) terminal of the auger motor with a
voltmeter. Connect the dispenser to the power
source. Press and hold the appropriate dispense
switch. After a delay of about .6 seconds, the
indication must be between +4.0 and +24.5 volts
dc.
If the voltage is present as described, the hopper
motor control circuitry is operating properly.
If the voltage is not present as described, replace the
control circuit board.
35135 012103