-11-
Revision 2/F3506
contactor is open and the normal power
supply to the oven thermostat is isolated. A
second normally open switch pole is closed
and this provides power to the 3 hour roast
timer.
If the roast timer is in the Hold (vertical)
position the timer switch contacts will be in
their normally closed position and supply
power directly to the Hold thermostat located
behind the control panel. The Hold
thermostat is factory set to 75°C (167°F) and
will directly supply power to the bottom
heating element as required to maintain its
preset temperature.
If the main thermostat is turned On, power will
also be supplied to the top outer element coil
through the first switch contact of the
thermostat front switch assembly. In this case
the thermostat heating light will also cycle On/
Off as the Hold thermostat maintains
temperature.
In the Roast-and Hold mode the 3 hour timer
can be set to a selected roasting time. During
this time period the normally open switch
contacts of the timer are closed. The timer
has two change over switches and in this
position one is used to supply power to its
timing motor and the other is used to switch
power directly to the main oven thermostat.
During the 3 hour timer run-down period the
oven temperature will be controlled by the
main oven thermostat to the set temperature
and operate as previously described.
When the 3 hour timer has run down and
reached the Hold position the two switch
contacts change over to their normally closed
position which isolates power from the timer
motor and the oven thermostat. It also
switches power back to the oven hold
thermostat. At this point the temperature
control is now maintained by the hold
thermostat as previously described. To
cancel the hold circuit the Roast-and-Hold
switch is turned Off. This turns off the
contactor which removes power from the 3
hour timer and closes the contactor pole on
the contactor that feeds the main oven
thermostat.
The factory preset hold thermostat can be
adjusted as required to change the holding
temperature if necessary. Refer Service
section for this procedure.
The following Troubleshooting Guide should
be used to identify any incorrect oven
operation. On correct identification of the
operating fault the Troubleshooting Guide will
make reference to the corrective action
required, or refer to the Fault Diagnosis
section and/or Service section to assist in
correction of the fault.