Fan Relay - Viking VDSC548T Series Service Manual

Service Diagnostics and Procedures

Fan Relay

The EOC is designed to operate a two-speed
cooling motor. The VDSC5 Series Touch Range
utilizes a one-speed motor so both the HI and LO
speeds are jumped together on the board. On
initial startup, the EOC selects the Fan Power relay
(K8) and the LO speed (K9). When the oven temp
reaches 250˚F, the board will switch the speed
relay to HI. However, both are jumped together so
this change is not noticed. If a fan error is shown,
proceed with the test shown below.
When the unit is switched ON, 12 VDC is sent to
both relay coils. A red LED in front of each coil
verifies coil voltage is being sent to that particular
relay. However, this does not indicate that the relays
are functioning.
To test, disconnect power and remove P11 Molex
plug. Reconnect power and access the diagnostic
procedures shown on page 73 to select the COOL
FAN H (Hi) parameter. With your meter set for AC
voltage, check between neutral and the terminal
(refer to photo below). The reading should be
120 VAC. If 0 volts are shown and the red LED is lit,
then the EOC is defective.
Fan–Hi Speed
K8
K9
© 2011 Viking Preferred Service
Switch the parameter to COOL FAN L (Lo) and
depress the "SELECTOR KNOB". Both relays should
be engaged. With your meter set for AC voltage,
check between neutral and the terminal (refer to
photo below). The reading should be 120 VAC. If
0 volts and the red LED's are lit, then the EOC is
defective.
Fan–Lo Speed
K8
K9
78