Control Board Diagnosis; Line Break Relay; Bake Element - Viking VDSC548T Series Service Manual

Service Diagnostics and Procedures

Control Board Diagnosis

With the control board assembly removed (see
Control Board Removal section, page 113), the
following components can be diagnosed without
removal of the components:

Line Break Relay

The line break relay breaks the L2 side of line
voltage. As the relay is energized, the relay closes
and allows L2 to the convection, broil and bake
element. Locate the line break relay on the control
board. The relay will have a red wire and a yellow
wire connected to it. The red wire is L2 input from
the main power supply and the yellow wire supplies
L2 line break relay energizes.
Line Break Relay
When heating is selected by the control input,
12 VDC is sent to the line break relay coil. A red
LED in front of the coil verifies coil voltage is being
sent to the relay. However, this does not indicate
that the relay is functioning.
To check the relay contacts, verify input voltage to
the relay between the red (L2) and black (L1) wire at
the main terminal block. You should read 240 VAC.
Select a cooking program. When the relay contact
is closed (red LED lit at base of relay) check for
240 VAC between the yellow and black (L1) wire.
If 0 VAC is read, disconnect power and remove the
red and yellow wire off the relay. Using your
Ohmmeter, check for continuity between the two
relay contacts. When the relay is not energized,
infinite ohms should be measured. If 0 Ohms is
found, this indicates a bad relay and the control
board should be replaced.
© 2011 Viking Preferred Service
Line Break Relay

Bake Element

Locate the P5 connector and the line break relay
on the control board. The P5 connector will have a
Molex plug containing a blue (30" RH oven Only on
48" models), black, and an orange wire.
The blue wire goes to the outer bake element on the
30", 36" and RH 30" oven on the 48" models.
On ALL models, the Orange wire goes to the inner
bake element (Both LH and RH), and the
black wire is L1 input from the main power supply..
P-5
Line Break Relay
With the power off and the Molex connector
removed from the P5 control board connection,
use an Ohmmeter to measure resistance between
the blue wire in the Molex plug and the yellow
wire from the line break relay. This will measure the
resistance of the outer bake element and should
be approximately 37 . Likewise, the inner bake
element can be measured by reading resistance
between the orange/black wire in the Molex plug
and the yellow wire from the line break relay. A
resistance reading of approximately 37
be found. If either element fails to read resistance,
remove element to repair or replace (see Bake
Element, page 112).
P-5
Line Break Relay
should
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