Control Board - Bunn FMD-3 Operating & Service Manual

SERVICE (cont.)

CONTROL BOARD

FIG. 7 CONTROL BOARD
Location:
The Control Board is located behind the lower front
access cover mounted on the component bracket.
Test Procedure:
Liquid Level Control Circuitry:
1. Disconnect the dispenser from the power source.
2. Disconnect the six pin connector from J3 of the
control board.
3. With a voltmeter, check the voltage across pins 5 &
6 of the six pin connector on the wiring harness.
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
Diagrams and check the dispenser wiring harness.
5. Reconnect the six pin connector of the wiring har-
ness to J3 of the control board.
6. Disconnect the four pin connector from J4 of the
control board.
7. With a voltmeter, check the voltage across pins 1 &
4 of the four pin connector on the wiring harness.
Connect the dispenser to the power source. The
indication must be:
a) 120 volts ac for two wire 120 volt models, three
wire 120/208 volt and 120/240 volt models.
b) 240 volts ac for two wire 240 volt models.
c) 230 volts ac for two wire 230 volt models.
8. Disconnect the dispenser from the power source.
If voltage is present as described, proceed to step 9.
If voltage is not present as described, refer to the Wiring
Diagrams and check the dispenser wiring harness.
9. Reconnect the four pin connector of the wiring
harness to J4 of the control board.
10. Disconnect the ten pin connector from J2 of the
control board.
11. Carefully connect a piece of insulated jumper wire
to pin 10 (top right) of J2 on the control board.
Keep the other end of this wire away from any metal
surfaces of the dispenser.
12. With a voltmeter, check the voltage across the
terminals of the inlet solenoid valve. Connect the
dispenser to the power source. The indication
must be:
a) 120 volts ac for two wire 120 volt models, three
P1637.40
wire 120/208 volt and 120/240 volt models,
b) 240 volts ac for two wire 240 volt models,
c) 230 volts ac for two wire 230 volt models, after
a delay of approximately 10 seconds.
13. Touch the free end of the jumper wire to the dis-
penser housing. The indication must be 0.
14. Move the jumper wire away from the housing. The
indication must, again, be:
a) 120 volts ac for two wire 120 volt models, three
wire 120/208 volt and 120/240 volt models,
b) 240 volts ac for two wire 240 volt models,
c) 230 volts ac for two wire 230 volt models, after
a delay of approximately 5 seconds.
15. Disconnect the dispenser from the power source
and remove the jumper wire.
If voltage is present as described, proceed to step
16.
If the voltage is not present as described, replace the
control circuit board.
16. Reconnect the ten pin connector of the wiring har-
ness to J2 of the control board.
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