Thermador C271 Service Manual - page 76
Convection Roast Pre-Heat Mode
Sequence Of Events:
1)
K4, K9, K1O, K11 relays close.
2)
K4 relay energizes both cooling motors; air flow from cooling motor
closes the “air switch” contacts. The completed “air switch” circuit signals
the board {signal voltage).
Note: if the air switch circuit is not completed within 40 seconds, the board
will interpret a cooling fan fault and display an f34 error code for the
upper oven, and an F64 error code for the lower oven.
3)
K11 relay closes and activates the convection motor. Note: the convection
motor will stop when the oven door is opened during any convection
mode.
4)
Pin header P14 on the relay board sends 24 VDC to the double line break
relay (DLB) coil. When the coil is energized; the DLB contacts close.
Current flows from L1 to one leg of the bake, broil, and convection
elements.
5)
Convection relay K10 and broil relay K9 alternately open and close and
send current from L2 to the other leg of the convection and broil elements,
the convection element is on for 30 seconds, and the broil element is on for
30 seconds during each 1-minute cycle.
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