Viking VGSO166 Service Manual page 23

Service Diagnostics and Procedures Service Diagnostics and Procedures
Thermostat Timer Testing (continued)
AT5 and AT6. The thermostat timer sends power to
the selector switch for bake and broil via terminal
AT4. The thermostat timer sends power to the
selector switch for convection via terminal AT3.
With Volt-Ohm meter set for voltage, measure
voltage between AT1 and AT2. If 120 VAC is not
present, check supply wire and repair replace as
necessary. With selector set for bake or broil, 120
VAC should be found between AT4 and ground.
If no voltage is present, replace the thermostat
timer. With the selector set for convection, 120 VAC
should be found between AT3 and ground. If no
voltage is present, replace the thermostat timer.
AT6
AT5
AT1
© 2009 Viking Preferred Service
AT3
AT4
AT2
F1 – Shorted probe
1. With Volt-Ohm meter set for resistance,
remove the wires from Thermostat Timer
terminals AT5 and AT6 and measure the
resistance across them.
2. If zero or infinite resistance, replace the RTD.
3. If resistance is in range per RTD chart on
page 20, check each wire to ground.
4. If resistance is present, the RTD is grounded
and the physical wires will need to be checked
for a grounded connection.
F3 – Controller Malfunction
1. With Volt-Ohm meter set for resistance,
remove the wires from thermostat timer
terminals AT5 and AT6 and measure the
resistance across them.
2. If resistance is in range per RTD chart on
page 20, verify output at thermostat timer.
3. With unit set for bake or broil, 120 VAC should
be present from AT4 to ground.
4. If no voltage is present, replace thermostat
timer.
5. If voltage is present, verify wiring between
thermostat timer and selector (BA and BR).
6. With unit set for convection, 120 VAC should
be present from AT3 to ground.
7. If no voltage is present, replace thermostat
timer.
8. If voltage is present, verify wiring between
thermostat timer and selector (CV).
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