Drain Motor; Moisture Sensor - Viking FDB451 Service Manual

Troubleshooting
To avoid risk of electrical shock, personal injury, or death, disconnect electrical power source to unit, unless test
procedures require power to be connected. Discharge capacitor through a resistor before attempting to service.
Ensure all ground wires are connected before certifying unit as repaired and/or operational.
(Some measurements require power and others require the unit not to be powered.)

Drain Motor

The dishwasher uses a drain motor to remove
water from the tub at timed intervals during
the wash cycle. In the drain mode, voltage
between P6-4 and neutral should be 120
VAC. If voltage is measured, unplug the wires
to the drain motor and using an ohmmeter,
check for approximately 15.1 Ω ohms at the
valve. If 0 Ω ohms are read, replace the drain
pump. If readings are correct, remove pump
and check for obstructions in the drain pump
(see Drain Motor Disassembly procedure,
page 27 ).
P-6
P-10
Note: Testing the drain motor can be
achieved in the diagnostic mode.
38
! WARNING

Moisture Sensor

The dishwasher uses a moisture sensor that
is mounted in the base pan of the dishwash-
er. Any moisture that comes in contact with
the sensor
will cause the unit to stop filling, operate the
drain pump, and signal an error code. If the
sensor is open, an open fail code will sig-
nal (see Fail Codes, page 12). Resistance
between P8-1 and P8-2 should be 175K Ω
ohms.
P-8
P-6
P-10
P-8
©2012 Viking Preferred Service