Liquid Level Board And Level Probe - Bunn SRUA Operating & Service Manual

SERVICE (cont.)

LIQUID LEVEL BOARD AND LEVEL PROBE

FIG.10 LIQUID LEVEL BOARD AND
LEVEL PROBE
Location:
The liquid level board is located behind the lower
front access panel, to the right of center on the
component bracket. The level probe is located on the
right front of the upper component bracket.
Test Procedures:
1. Disconnect the brewer from the power source.
2. Disconnect the blue wire (T1) and the pink wire
(T4).
3. Check for 230 volts ac across terminals (T2) and
(T3) with the ON/OFF switch in the "ON" position.
4. Disconnect the brewer from the power source.
If voltage is present as described, proceed to #5.
If voltage is not present as described, refer to wiring
diagram and check the brewer wiring harness.
5. Reconnect the blue wire to T1 on the liquid level
board.
6. Carefully connect a piece of insulated jumper wire
to T4. Keep the other end of this wire away from
any metal surface of the brewer.
7. Touching the free end of the jumper to the brewer's
frame simulates a "FULL" condition, preventing
jumper from touching the brewer's frame simu-
lates "NEED WATER" condition. Connect the brewer
to the power source, simulate each condition while
measuring the voltage between T1 and T3 on the
liquid level board. The indication should be 0 volts
with jumper touching the frame and 230 volts ac
not touching the frame. Repeat these several times.
Keep in mind there is an approximate five second
delay for output to stabilize.
8. Disconnect the brewer from the power source and
remove the jumper wire from T4.
If voltage is present as described, liquid level board is
P2116.40
operating properly, proceed to #9.
If voltage is not present as described, replace the liquid
level board.
9. Reconnect the pink wire to T4.
10. Remove the two #8-32 screws securing the level
probe to the component bracket.
11. Gently pull the probe out of the component bracket
and inspect for corrosion. Replace if necessary.
12. Place the probe so that neither end is in contact
with any metal surface of the brewer.
13. Connect the brewer to the power source and
simulte the "FULL" and "NEED WATER" conditions
by touching the end of the probe to any metal
surface of the brewer. Measure the voltage be-
tween T1 and T3 on the liquid level board. The
indication should be 0 volts with the probe touch-
ing the frame and 230 volts ac not touching the
frame. Keep in mind there is an approximate delay
of five seconds for output to stabilize.
14. Disconnect the brewer from the power source.
If voltage is present as described, reinstall the level
probe, the liquid level board and level probe are
operating properly.
If voltage is not present as described, check the pink
wire on the level probe from liquid level board T4.
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