© 2010 Viking Preferred Service
42
Service Diagnostics and Procedures
Relay Board Diagnosis
Convection Fan
Locate the P3 connector and line break relay.
The P3 connector will have a Molex plug containing
4 wires:
(1)
& (2) A blue wire jumper between terminals
REV and FWD
(3) orange/white wire–LO speed capacitor
(4) orange/black wire–HI speed capacitor
Convection Operation
The main power and speed are controlled by the
EOC by the Speed relay (K7) and the main control
power relay (K5). The K6 relay (Directional) is not
used on this series of ovens. The main control
(power) relay is a SPDT relay and controls all
functions of the convection fan system. The photo
below
shows the relay energized.
Low Speed–Clockwise (FWD)
When closed, it sends power through the relay and
out to the LO speed relay contact.
The output from the relay is connected to the
C (common terminal). Because the relay is not
used, both the FWD and REV contacts are jumped
together.
Clockwise (FWD)–High Speed
The speed relay is a SPDT relay. When not
energized, the LO circuit is energized through the
C terminal of the relay. The N.O. terminal is now
closed resulting in the unit running at a higher
speed.
Testing Relay Board
Use a volt meter to measure 120 volts AC between
the orange/white (low speed) when K7 is Not
energized and the orange/ black (high speed) with
K7 energized wire in the Molex plug and the neutral
terminal block.
LED
K7
K6
K5
LED
K7
K6
K5
LED
K7
K6
K5