Thermador SMW 272 B, Service Manual, Page: 80 / 84

Page 78
Lower O ven Section SMW O ven Service Manual
L2
L1
Cooling
Fan
K6
Cooling Fan
Relay
N.O.
Stalled
Fan Relay
Air
Switch
K8
L1 Relay
Bake
K1
Bake
Relay
N.O.
Conv.
N.O.
K2
Broil
Relay
K3
Conv.
Relay N.O.
K4
Conv.
Motor
Relay
Conv.
Motor
N.O.
Broil
29 Seconds
15 Amps
30 Seconds
11 Amps
N.O. = Normally Open Contacts
N.C. = Normally Closed Contacts
= Neutral Return
N.C.
N.O.
High-Temp
Cutout
Stalled Fan
Relay Contacts
N.O.
Press the CO N VECTIO N RO AST keypad and select an oven temperature and the following events will
occur on the relay board:
• Line Relay
K8
closes.
• Cooling Fan Relay
K6
closes and turns the Cooling Fan on.
• Cooling Fan air flow closes the Air Switch and activates the Stalled Fan Relay.
• The Stalled Fan Relay contacts close and supply L1 to one side of Relay
K8 (already activated)
.
• The
L1
Relay connects L1 line voltage to the Convection and Broil Elements.
• Broil Relay
K2
and Convection Relay
K3
alternately open and close, and connect the L2 (120-volt)
line to the Convection and Broil elements. N O TE: The Convection Element is on for 30-seconds,
and draws 11-amperes during each 1-minute cycle. The Broil Element is on for 29-seconds and
draws 15-amperes during each 1-minute cycle.
• Convection Motor Relay
K4
closes and activates the Convection Motor.
Convection Roast Cycle — Convection Roast Preheat
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